No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Effects of Phosphatidylserine on Exercise Capacity during Cycling in Active Males
Abstract
The purpose of the study was to investigate the effects of 750 mg of soybean-derived phosphatidylserine, administered daily for 10 d, on exercise capacity, oxygen uptake kinetic response, neuroendocrine function, and feeling states during exhaustive intermittent exercise.
Following preliminary testing, fourteen active males completed a staged intermittent exercise protocol on two further occasions (T1 and T2) separated by 16 +/- 1 d. The protocol consisted of three 10-min stages of cycling at 45, 55, and 65% VO2max, followed by a final bout at 85% VO2max that was continued until exhaustion. Approximately 5 d after T1 the subjects were assigned, in a double-blind manner, to either phosphatidylserine (PS) or placebo (P). Breath-by-breath respiratory data and heart rate were continually recorded throughout the exercise protocol, and blood samples were obtained at rest, during the rest periods within the protocol (Post-55, Post-65), at the end of exercise (Post-85), 20 min after the completion of exercise (postexercise), and the day following exercise (Post-24 h).
The main finding of this study was that supplementation had a significant effect on exercise time to exhaustion at 85% VO2max (P = 0.005). The exercise time to exhaustion in PS increased following supplementation (7:51 +/- 1:36 to 9:51 +/- 1:42 min:s, P = 0.001), whereas P remained unchanged (8:09 +/- 0:54 to 8:02 +/- 0:54 min:s, P = 0.670). Supplementation did not significantly affect oxygen kinetic mean response times (MRT(on) and MRT(off)), serum cortisol concentrations, substrate oxidation, and feeling states during the trial.
This is the first study to report improved exercise capacity following phosphatidylserine supplementation. These findings suggest that phosphatidylserine might possess potential ergogenic properties.
... Three additional resources were added from the reference sections of the four initially reviewed articles. The full texts of all seven articles were retrieved and thoroughly reviewed [12][13][14][15][16][17][18] . Figure 1 provides a visual representation of the selection process. ...
... Figure 1 provides a visual representation of the selection process. Seven randomized clinical trials were found to meet the inclusion criteria and were included in this review [12][13][14][15][16][17][18] . (2) Hormone levels There was a significant increase in testosterone to cortisol ratio in the treatment groups. ...
... All the studies included in this review were published in English during the years of 1990-2011. The countries represented in the selected articles include: Germany [12] , the United Kingdom [13,14,15,18] , Italy [16] , and the United States [17,18] . The ages of participants ranged from 20-55 with a total sum of 94 participants. ...
This review aims to critically evaluate the existing evidence derived from randomized clinical trials to determine the effectiveness of phosphatidylserine in enhancing athletic performance. Extensive searches were conducted in databases including PubMed, ClinicalTrials.gov, Google Scholar, Embase, Web of Science, CINAHL, and Medline. Among the initially identified 538 articles with potential relevance, a thorough assessment of full-text articles was performed, resulting in the inclusion of seven studies that satisfied all predefined inclusion criteria. All studies were evaluated as having a low risk of bias. Five of the included studies reported statistically significant differences before and after intervention, thus providing support for the use of phosphatidylserine as a supplement to support athletic performance. However, despite these promising results obtained from clinical trials, the current evidence remains insufficient to firmly endorse the use of phosphatidylserine for its impact on athletic performance.
... 400 or 800 mg/day) for 10 days and found the highest dose decreased plasma cortisol concentration in healthy sedentary men. Another study evaluated PS supplementation 750 mg/ day for 10 days; no change was found in serum cortisol levels after cycling protocol (Kingsley et al., 2006b). In this sense, these data indicate that the chronic PS effect on the catabolic state is still contradictory. ...
... The mechanisms by which PS and PSBCAA affect corticosterone have been associated with the activation of antagonistic action of HPA axis (Monteleone et al., 1990). Kingsley et al. (2006b) evaluated PS supplementation for 10 days and no changes were found in serum cortisol levels after an intermittent cycling protocol in physically active young men. However, a more extended period of PS supplementation was sufficient (>2 weeks) to attenuate the cortisol levels (Cenacchi et al., 1993). ...
... Specifically, in relation to PS supplementation and performance, Kingsley et al. (2006b) reported an ergogenic effect in physically active men. These authors also observed an increased time to exhaustion (TE) after 10 days of supplementation compared to PLA, corroborating with our data. ...
Acute phosphatidylserine (PS) or branched-chain amino acids (BCAA) supplements alone may have an adrenocorticotropic hormone, cortisol suppressive effect and increase the testosterone/cortisol ratio, but the associated effect of these supplements during a period of high-intensity physical stress is not yet known. The study investigated the effects of chronic PS supplementation alone and combined with BCAA during high-intensity interval training (HIIT) on training volume tolerance, anabolic-catabolic balance and stress biomarkers in rats. Thirty-three rats were separated into: placebo (PLA, n=11), PS alone (n=11) and combined with BCAA (PSBCAA, n=11). Groups performed swimming sessions of HIIT (5 series × 1 min × 1 min recovery; external load equivalent to 13% of body mass) and nine recovery sessions of moderate-intensity training (30 min at 5% of body mass) alternately. One-way ANOVA was used to compare biochemical variables and two-way ANOVA was calculated to compare training volume. Training volume performed (TVP) was higher in first, fourth, fifth, sixth, and eighth HIIT sessions in the PS group in comparison to PLA (P<0.05). TVP was higher in the fourth session in PSBCAA compared to PLA. There were no differences in TVP during the sessions between PS and BCAA groups. Creatine kinase (CK) was lower in PSBCAA in comparison to PS alone (P=0.03) and PLA (P=0.04) after the experimental period. Testosterone concentration was enhanced in PSBCAA group compared to PLA (P=0.01); testosterone/corticosterone ratio was higher in PSBCAA compared to PS (P=0.05) and PLA (P=0.004) after protocol. PS combined with BCAA increases testosterone concentration and testosterone/corticosterone ratio, demonstrating an enhancement of anabolic state in trained rats.
... Phosphatidylserine supplementation has been reported to improve neurocognitive function of older patients with cognitive disorders and Alzheimer's disease [15][16][17][18][19][20][21]. Furthermore, phosphatidylserine has proven to have ergogenic properties, improving the regeneration of skeletal muscle, reducing oxidative stress and modulating the endocrine response during excessive sport, with no major side-effects [22][23][24][25][26]. Phosphatidylserine has been shown to inhibit the production of pro-inflammatory cytokines [27][28][29] and promote anti-inflammatory pathways at the cellular level [30]. ...
... Phosphatidylserine supplementation has already shown benefits in patients with cognitive disorders [15,[17][18][19] and in regeneration after physical activity [22][23][24][25][26] in clinical settings. Phosphatidylserine is commercialized and can be administrated without prescription. ...
... Phosphatidylserine is commercialized and can be administrated without prescription. As side effect only mild gastrointestinal side-effects by high supplementation dosage were reported [22][23][24][25][26]. Due to its proven safety, phosphatidylserine supplementation represents a viable candidate as a cardio-protection strategy in AMI with immediate application in clinics. ...
Phosphatidylserines are known to sustain skeletal muscle activity during intense activity or hypoxic conditions, as well as preserve neurocognitive function in older patients. Our previous studies pointed out a potential cardioprotective role of phosphatidylserine in heart ischemia. Therefore, we investigated the effects of phosphatidylserine oral supplementation in a mouse model of acute myocardial infarction (AMI). We found out that phosphatidylserine increases, significantly, the cardiomyocyte survival by 50% in an acute model of myocardial ischemia-reperfusion. Similar, phosphatidylserine reduced significantly the infarcted size by 30% and improved heart function by 25% in a chronic model of AMI. The main responsible mechanism seems to be up-regulation of protein kinase C epsilon (PKC-ε), the main player of cardio-protection during pre-conditioning. Interestingly, if the phosphatidylserine supplementation is started before induction of AMI, but not after, it selectively inhibits neutrophil's activation, such as Interleukin 1 beta (IL-1β) expression, without affecting the healing and fibrosis. Thus, phosphatidylserine supplementation may represent a simple way to activate a pre-conditioning mechanism and may be a promising novel strategy to reduce infarct size following AMI and to prevent myocardial injury during myocardial infarction or cardiac surgery. Due to the minimal adverse effects, further investigation in large animals or in human are soon possible to establish the exact role of phosphatidylserine in cardiac diseases. Citation: Schumacher, D.; Curaj, A.; Staudt, M.; Cordes, F.; Dumitrascu, A.R.; Rolles, B.; Beckers, C.; Soppert, J.; Rusu, M.; Simsekyilmaz, S.; et al. Phosphatidylserine Supplementation as a Novel Strategy for Reducing Myocardial Infarct Size and Preventing Adverse Left Ventricular Remodeling.
... Research on PS shows it has unique properties reducing cortisol levels after exercise (8,11,29,30,36), which would lead to an improved testosterone to cortisol ratio (36). Furthermore, research on PS has shown it to enhance mood, performance, recovery, immunity, decision making, accuracy, and cognition (8,11,18,19,24,33). The purpose of this article is to discuss PS, review the literature on the supplement PS, and describe which population might benefit most from its supplementation. ...
... Jäger et al. (15) also state that the ratio for PS in the phospholipid pool for the lungs is 7.4%, testes 6.4%, kidneys 5.7%, liver 3.8%, skeletal muscle 3.3%, heart 3.2%, and blood plasma 0.2%. accelerated loss of adipose tissue, potential antioxidant functions, necessary for enzyme cofactors, initiates cell phagocytosis through apoptosis signaling, and improved cell integrity (8,15,17,21,24,40), as well as the possible ability to prolong exercise time to exhaustion (18,19). One unique attribute to PS is its ability to blunt cortisol (8,11,29,30,36), thus improving the testosterone to cortisol level (36), and providing a favorable hormonal status for training individuals. ...
... Kingsley et al. (18) studied the effects of 750 mg/d S-PS supplemented for 10 days on 14 recreationally active males. The study (double-blind nonrepeated measures) assessed the exercise capacity, neuroendocrine function, oxygen uptake, kinetic response, and perceived feeling states during and immediately following intermittent cycling. ...
POSITIVE ADAPTATIONS FROM TRAINING ONLY OCCUR WHEN RESTORATION EXCEEDS THE CATABOLIC DOSAGE RECEIVED DURING TRAINING. NUMEROUS FACTORS AFFECT RECOVERY, SUCH AS ADDITIONAL LIFE STRESS. THE CUMULATIVE STRESS CAN NEGATIVELY AFFECT RESTORATION, AS WELL AS PERFORMANCE. ONE UNIQUE SUPPLEMENT, PHOSPHATIDYLSERINE (PS), HAS UNIQUE PROPERTIES ON RECOVERY AND HUMAN PERFORMANCE, AND HAS ALSO BEEN SHOWN TO ENHANCE MOOD, IMMUNITY, DECISION MAKING, AND ACCURACY. ATHLETIC PERFORMANCE IS AFFECTED BY SEVERAL FACTORS, IN WHICH PS MIGHT BE ABLE TO FACILITATE ENHANCED PERFORMANCE. THE PURPOSE OF THIS ARTICLE IS TO REVIEW THE LITERATURE ON PS AND SUGGEST HOW IT CAN BE IMPLEMENTED FOR THE ATHLETE.
... Oral PS also attenuates the "stress response"; supplementation with PS 300 mg/d for 1 mo [120], 400 mg for 21 d [121], 600 mg for 21 d [121], 600 mg for 10 d [122], 800 mg for 10 d [123], 800 mg for 21 d [121], or 800 mg for 14 d [124] suppressed the typical exercise-induced spikes in the serum concentrations of ACTH and cortisol that accompanied the initiation of cycling exercise in healthy young physically conditioned men [123,124] or exposure to acute psychological stress in healthy young men and women [120,121]. In one study, supplementation with PS increased subjects' exercise capacity [125]. Together these findings indicate that supplemental PS interacts with neuronal cell membranes within the human brain to blunt the typical pituitary ACTH secretory response to hypothalamic stimuli, reduce resting serum cortisol concentrations, and attenuate the expected hypersecretion of cortisol during and after exercise [118][119][120][121][122][123][124][125]. ...
... In one study, supplementation with PS increased subjects' exercise capacity [125]. Together these findings indicate that supplemental PS interacts with neuronal cell membranes within the human brain to blunt the typical pituitary ACTH secretory response to hypothalamic stimuli, reduce resting serum cortisol concentrations, and attenuate the expected hypersecretion of cortisol during and after exercise [118][119][120][121][122][123][124][125]. ...
... In addition to the absence of reports in the published scientific literature of adverse reactions concerning oral supplementation with PS, the safety of dietary supplementation with PS has been demonstrated in many human clinical trials [57,63,65,[93][94][95][96][97][98][99][100][101][102][103][104][105][106][107][108][109][110][111][112][119][120][121][122][123][124][125][126][127] and has been documented in detail by several investigators [63,102,105,126,127]. The FDA also endorsed the safety of daily dietary supplementation with up to 300 mg of PS [112]. ...
The aim of this study was to assess the roles and importance of phosphatidylserine (PS), an endogenous phospholipid and dietary nutrient, in human brain biochemistry, physiology, and function.
A scientific literature search was conducted on MEDLINE for relevant articles regarding PS and the human brain published before June 2014. Additional publications were identified from references provided in original papers; 127 articles were selected for inclusion in this review.
A large body of scientific evidence describes the interactions among PS, cognitive activity, cognitive aging, and retention of cognitive functioning ability.
Phosphatidylserine is required for healthy nerve cell membranes and myelin. Aging of the human brain is associated with biochemical alterations and structural deterioration that impair neurotransmission. Exogenous PS (300-800 mg/d) is absorbed efficiently in humans, crosses the blood-brain barrier, and safely slows, halts, or reverses biochemical alterations and structural deterioration in nerve cells. It supports human cognitive functions, including the formation of short-term memory, the consolidation of long-term memory, the ability to create new memories, the ability to retrieve memories, the ability to learn and recall information, the ability to focus attention and concentrate, the ability to reason and solve problems, language skills, and the ability to communicate. It also supports locomotor functions, especially rapid reactions and reflexes.
Copyright © 2015 Elsevier Inc. All rights reserved.
... The supplementation did not significantly attenuate these responses Kingsley et al. (2006a) The effects of 750 mg of soybean-derived phosphatidylserine, administered for 10 days, on exercise capacity, oxygen uptake kinetic response, neuroendocrine function, and feeling states during exhaustive intermittent exercise The supplementation had a significant effect on exercise time to exhaustion. Supplementation did not significantly affect oxygenkinetic mean response times, serum cortisol concentrations, substrate oxidation, and feeling states during the trial Kingsley et al. (2006b) other investigations showed that supplementation with soy-derived phosphatidylserine was not effective in attenuating the perceived muscle soreness, as well as markers of oxidative stress and acute inflammation following exhaustive running (Kingsley et al., 2005(Kingsley et al., , 2006a, but it improves exercise capacity (Kingsley et al., 2006b). The review of investigations of the effects of consumption of the soy-derived fats, fatty acids and oils on athlete health and endurance is given in Table 8. ...
... The supplementation did not significantly attenuate these responses Kingsley et al. (2006a) The effects of 750 mg of soybean-derived phosphatidylserine, administered for 10 days, on exercise capacity, oxygen uptake kinetic response, neuroendocrine function, and feeling states during exhaustive intermittent exercise The supplementation had a significant effect on exercise time to exhaustion. Supplementation did not significantly affect oxygenkinetic mean response times, serum cortisol concentrations, substrate oxidation, and feeling states during the trial Kingsley et al. (2006b) other investigations showed that supplementation with soy-derived phosphatidylserine was not effective in attenuating the perceived muscle soreness, as well as markers of oxidative stress and acute inflammation following exhaustive running (Kingsley et al., 2005(Kingsley et al., , 2006a, but it improves exercise capacity (Kingsley et al., 2006b). The review of investigations of the effects of consumption of the soy-derived fats, fatty acids and oils on athlete health and endurance is given in Table 8. ...
Soybean Glycine max (L.) Merr. is a major leguminous crop of global importance with widespread applicability and economic value of its products in the national as well as the global market. The aim of the presented investigations was to review the experimental articles and patents referring to the application of soybean-based products for sportsman published in the period 1970-2019. The greatest number of papers and patents were published in the years 2010-2019 by researchers affiliated in the USA, China and Japan. Altogether, 64 patents and 39 experimental articles were recorded. The inventors patented the food supplements (in a majority), sportswear and devices enhancing protection of athletes during their sport activities. The greatest number of experimental articles was devoted to the impact of soy-based products use on athletes’ health, the evaluation of the quality of the products, as well their acceptability by sportsmen.
... 6 A double-blind, placebo-controlled clinical trial showed that soy-derived PL increased exercise times to exhaustion. 7 Soy-derived PL significantly reduced muscle soreness and attenuated post-exercise perception of fatigue in humans. 8 However, the data involving the effects of ω-3 LCPUFA and phospholipids on physical fatigue were inconsistent. ...
... Moreover, double-blind parallel studies indicated that the administration of soybean-derived phospholipids significantly increased the time to exhaustion in active males. 7,39 Guen et al. suggested that a 9-week DHA-enriched supplementation improved the endurance exercise capacity in adult rats, which was in accordance with the result obtained for aerobic exercise in the present study. 40 Suzumura et al. showed that fish oil supplementation enhanced endurance in women. ...
The beneficial effects of nonpolar DHA/EPA in triacylglycerol (TG) and ethyl ester (EE) forms as well as terrestrial phospholipids on physical fatigue have been widely reported. However, the results involving the effects were inconsistent, and the reason might be that it usually ignored the differences between physical fatigue induced by aerobic and anaerobic exercise. Additionally, it has been reported the significant improvement of DHA/EPA esterified to phospholipids (DHA/EPA-PLs) on many fields but not physical fatigue. Therefore, the effects of DHA/EPA-PLs on physical fatigue induced by aerobic and anaerobic exercise were evaluated and compared with L-carnitine and astaxanthin using swimming and running exhaustion test in mice, respectively. The results showed that DHA/EPA-PL and L-carnitine had significant effects on the performance of aerobic exercise, while astaxanthin had remarkable effect on the performance of anaerobic exercise. The possible underlying mechanisms indicated that DHA/EPA-PL significantly promoted the carbohydrate and lipid metabolism as well as mitochondrial respiratory chain and tricarboxylic acid cycle in muscle. The study represented a potential novel candidate or targeted dietary patterns for alleviating physical fatigue.
... Some studies of a single kind of BCAA have shown that leucine accelerates protein synthesis [18,19] and that valine supplementation before exercise suppresses the elevation of corticosterone levels and the depletion of glucose during exercise in rats [20]. Serine, which is known as a substrate of phosphatidylserine, was reported to reduce the feeling of fatigue, improve exercise performance [21,22] and reduce the increase in cortisol during exercise [23]. In these reports, 400-750 mg of phosphatidylserine caused significant effects. ...
... These data indicated that the use of serine was enhanced in the AA group in the study. It was reported that supplementation with phosphatidylserine, synthesized by serine, attenuated the perception of fatigue during exercise and improved exercise capacity [21,22], which suggested that the increase in serine might contribute to the phosphatidylserine production that affected the feeling of fatigue in the study. ...
Although several kinds of amino acids (AAs) are known to affect physiological actions during exercise, little is known about the combined effects of a mixture of several AAs on fatigue during exercise. The aim of the present study was to investigate the effect of an AA mixture supplement containing arginine, valine, and serine on exercise-induced fatigue in healthy volunteers. These AAs were selected because they were expected to reduce fatigue during exercise by acting the positive effects synergistically. A randomized, double-blinded, placebo-controlled crossover trial was conducted. Thirty-nine males ingested an AA mixture containing 3600 mg of arginine, 2200 mg of valine, and 200 mg of serine or a placebo each day for 14 days. On the 14th day, the participants completed an exercise trial on a cycle ergometer at 50% of VO2max for 120 min. After the two-week washout period, the participants repeated the same trial with the other test sample. The participant’s feeling of fatigue based on a visual analog scale (VAS) and a rating of perceived exertion (RPE), as well as blood and physical parameters were evaluated. The feeling of fatigue based on VAS and RPE were significantly improved in AA compared to those in placebo. In the blood analysis, the increase in serum total ketone bodies during exercise and plasma tryptophan/branched-chain amino acids were significantly lower in AA than those in placebo. The present study demonstrated that supplementation with an AA mixture containing arginine, valine, and serine reduced the feeling of fatigue during exercise. The AA mixture also changed several blood parameters, which may contribute to the anti-fatigue effect.
... The potential neural benefit has led to investigations ex- amining the effects of PS supplementation on cognition, reaction time (RT), and acute physiological response to both physical and mental stress [11][12][13][14][15][16][17]. Acute ingestion of a multi- ingredient supplement containing 50 mg PS in combination with several other nutrients (α-glycerophosphocholine; cho- line bitartrate; vitamins B3, B6, and B12; folic acid; L-tyrosine; anhydrous caffeine; acetyl-L-carnitine; and naringin) has been shown to maintain RT to both visual and auditory stimuli and focus, following a high-intensity bout of exhaustive exer- cise [12]. ...
... In addition, supplementation with 400 mg/d of PS for 14 days has been shown to significantly increase cognitive function before and 60 minutes postexercise in resistance- trained college-aged men [17], whereas 200 mg/d of PS for 6 weeks in healthy men has been shown to significantly attenuate β-1 power (an indicator of activation associated with cognitive task demands and higher neurophysiological func- tion in right hemispheric frontal brain regions) before and after induced mental stress [11]. Dosages of 800 mg/d PS for 10 days have been reported to significantly blunt the adreno- corticotropic and cortisol response to exercise [16], and supplementation with 750 mg/d for 10 days has been shown to increase time to exhaustion in both runners [13] and cyclists [14]. In contrast, there are several studies that were unable to support any cognitive or ergogenic benefit from PS ingestion. ...
... There have been numerous articles published reporting that PS supplementation can affect endocrine function, specifically by blunting cortisol response to stress [3,10,11]. However, several studies have also reported no changes in endocrine function as a result of PS supplementation [12,13]. Very few studies have been performed examining the effects of PS supplementation on testosterone levels. ...
... In one article, Starks found no significant changes in testosterone levels after 10 days of supplementation with 600 mg of PS [4]. These equivocal findings on mood and endocrine response have been attributed to differences in training status, dose and duration of supplementation and the kind of physical and mental stress [1,13] . Due to the strenuous nature of the exercise protocol used in this study, only resistance trained individuals were allowed to participate. ...
ABSTRACT:
Phosphatidylserine (PS) is a phospholipid found in cell membranes of most animals and plants. PS has been shown to reduce stress and increase performance in runners, cyclists and golfers. The purpose of this study was to investigate the effects of a PS containing formulation on cognitive function, mood and endocrine response before and after intense resistance exercise.
18 lower body, resistance trained, college aged males ingested 14 days of supplement (IQPLUS Focus, providing 400 mg of soy-derived PS) and a Placebo (PL), in a randomized, double-blind, placebo controlled, cross-over manner. Following 14 days of supplementation, participants performed an acute bout of lower body resistance training. Mood (Profile of Mood States, POMS) and cognitive function (Serial Subtraction Test, SST) were measured prior to, 5 minutes after, and 60 minutes after exercise. Venous blood samples were collected prior to, and 5, 15, 25, 40 and 60 minutes after exercise. Blood samples were analyzed for plasma cortisol and testosterone. Data were analyzed using repeated measures ANOVA.
PS supplementation significantly reduced the time needed for a correct calculation on the SST by 20% (reduced by 1.27 s per calculation; PL: 6.4 s, PS: 5.13 s; p = 0.001), and reduced the total amount of errors by 39% (PL: 1.28 + .69, PS: .78 + .27, p = 0.53), and increased the amount of correct calculations by 13% (PL: 22.1 + 2.24, PS: 24.9 + 1.52, p = 0.07) prior to or in response to exercise compared to PL. Following exercise, there was no difference in SST scores between PS and PL. There were no significant changes in regards to mood or endocrine response to exercise as a result of PS supplementation.
PS supplementation significantly increased cognitive function prior to exercise. Improved cognitive function could benefit athletes and non-athletes alike. PS did not appear to affect mood or endocrine response prior to or following resistance exercise.
... These properties have led to additional investigations on the ability of phosphatidylserine to enhance recovery from exercise. A 750 mg dosing of phosphatidylserine for 7 days prior to an acute bout of exhaustive exercise resulted in significant improvements in sprint performance [20] and an increase in time to exhaustion during intermittent cycling exercise [21]. Starks and colleagues [15] reported a lowered stress response to moderate intensity cycling exercise (65% -85% VO 2 max) following 10 days of supplemention with 600 mg of phosphatidylserine, reflected by a reduced cortisol response to exercise. ...
... The CRAM supplement combined choline (as a-glycerophosphocholine and choline bitartrate) with phosphatidylserine , carnitine, an energy matrix (caffeine and tyrosine) and vitamins. Phosphatidylserine has been previously shown to enhance recovery following high-and moderate-intensity exercise [1,15,202122. In addition, Hoffman et al. ...
The purpose of this study was to examine the effect of acute and prolonged (4-weeks) ingestion of a supplement designed to improve reaction time and subjective measures of alertness, energy, fatigue, and focus compared to placebo.
Nineteen physically-active subjects (17 men and 2 women) were randomly assigned to a group that either consumed a supplement (21.1 ± 0.6 years; body mass: 80.6 ± 9.4 kg) or placebo (21.3 ± 0.8 years; body mass: 83.4 ± 18.5 kg). During the initial testing session (T1), subjects were provided 1.5 g of the supplement (CRAM; α-glycerophosphocholine, choline bitartrate, phosphatidylserine, vitamins B3, B6, and B12, folic acid, L-tyrosine, anhydrous caffeine, acetyl-L-carnitine, and naringin) or a placebo (PL), and rested quietly for 10-minutes before completing a questionnaire on subjective feelings of energy, fatigue, alertness and focus (PRE). Subjects then performed a 4-minute quickness and reaction test followed by a 10-min bout of exhaustive exercise. The questionnaire and reaction testing sequence was then repeated (POST). Subjects reported back to the lab (T2) following 4-weeks of supplementation and repeated the testing sequence.
Reaction time significantly declined (p = 0.050) between PRE and POST at T1 in subjects consuming PL, while subjects under CRAM supplementation were able to maintain (p = 0.114) their performance. Significant performance declines were seen in both groups from PRE to POST at T2. Elevations in fatigue were seen for CRAM at both T1 and T2 (p = 0.001 and p = 0.000, respectively), but only at T2 for PL (p = 0.029). Subjects in CRAM maintained focus between PRE and POST during both T1 and T2 trials (p = 0.152 and p = 0.082, respectively), whereas significant declines in focus were observed between PRE and POST in PL at both trials (p = 0.037 and p = 0.014, respectively). No difference in alertness was seen at T1 between PRE and POST for CRAM (p = 0.083), but a significant decline was recorded at T2 (p = 0.005). Alertness was significantly lower at POST at both T1 and T2 for PL (p = 0.040 and p = 0.33, respectively). No differences in any of these subjective measures were seen between the groups at any time point.
Results indicate that acute ingestion of CRAM can maintain reaction time, and subjective feelings of focus and alertness to both visual and auditory stimuli in healthy college students following exhaustive exercise. However, some habituation may occur following 4-weeks of supplementation.
... Therefore, these findings suggest that AA may enhance anaerobic capacity. In support of this finding, recent literature suggests that 10 days of soybean-derived phosphatidylserine supplementation can significantly increase the time-to-fatigue and total work performed in active males during an 85% VO 2 max cycling bout [40]. Phosphatidylserine is a soy bean-derived phospholipid that contains AA [41]. ...
... e anaerobic capacity. In support of this finding, recent literature suggests that 10 days of soybean-derived phosphatidylserine supplementation can significantly increase the time-to-fatigue and total work performed in active males during an 85% VO 2 max cycling bout [40]. Phosphatidylserine is a soy bean-derived phospholipid that contains AA [41]. Kingsley et al. (2006) hypothesized that phosphatidylserine supplementation may increase exercise capacity by delaying fatigue and sustaining intracellular calcium levels through an increase in the density of Ca 2+ ATPase pumps in the sarcoplasmic reticulum of skeletal muscle [40] . Collectively , these findings provide preliminary framework that AA may have ...
To determine the impact of AA supplementation during resistance training on body composition, training adaptations, and markers of muscle hypertrophy in resistance-trained males.
In a randomized and double blind manner, 31 resistance-trained male subjects (22.1 +/- 5.0 years, 180 +/- 0.1 cm, 86.1 +/- 13.0 kg, 18.1 +/- 6.4% body fat) ingested either a placebo (PLA: 1 g.day-1 corn oil, n = 16) or AA (AA: 1 g.day-1 AA, n = 15) while participating in a standardized 4 day.week-1 resistance training regimen. Fasting blood samples, body composition, bench press one-repetition maximum (1RM), leg press 1RM and Wingate anaerobic capacity sprint tests were completed after 0, 25, and 50 days of supplementation. Percutaneous muscle biopsies were taken from the vastus lateralis on days 0 and 50.
Wingate relative peak power was significantly greater after 50 days of supplementation while the inflammatory cytokine IL-6 was significantly lower after 25 days of supplementation in the AA group. PGE2 levels tended to be greater in the AA group. However, no statistically significant differences were observed between groups in body composition, strength, anabolic and catabolic hormones, or markers of muscle hypertrophy (i.e. total protein content or MHC type I, IIa, and IIx protein content) and other intramuscular markers (i.e. FP and EP3 receptor density or MHC type I, IIa, and IIx mRNA expression).
AA supplementation during resistance-training may enhance anaerobic capacity and lessen the inflammatory response to training. However, AA supplementation did not promote statistically greater gains in strength, muscle mass, or influence markers of muscle hypertrophy.
... PS accounts for 10% of all membrane glycerophospholipids. In one study, physically active males showed improved exercise capacity due to a greater concentration of PS in the body [51]. In addition, Starks et al. [52] demonstrated that increased PSs are effective in combating exercise-induced stress and preventing physiological deterioration. ...
The purpose of this study was to use traditional physical assessments combined with a metabolomic approach to compare the anthropometric, physical fitness level, and serum fasting metabolic profile among U22 soccer players at different competitive levels. In the experimental design, two teams of male U22 soccer were evaluated (non-elite = 20 athletes, competing in a regional division; elite = 16 athletes, competing in the first division of the national U22 youth league). Earlobe blood samples were collected, and metabolites were extracted after overnight fasting (12 h). Untargeted metabolomics through Liquid Chromatograph Mass Spectrometry (LC-MS) analysis and anthropometric evaluation were performed. Critical velocity was applied to determine aerobic (CV) and anaerobic (ARC) capacity. Height (non-elite = 174.4 ± 7.0 cm; elite = 176.5 ± 7.0 cm), body mass index (non-elite = 22.1 ± 2.4 kg/m2; elite = 21.9 ± 2.3 kg/m2), body mass (non-elite = 67.1 ± 8.8 kg; elite = 68.5 ± 10.1 kg), lean body mass (non-elite = 59.3 ± 7.1 kg; elite = 61.1 ± 7.9 kg), body fat (non-elite = 7.8 ± 2.4 kg; elite = 7.3 ± 2.4 kg), body fat percentage (non-elite = 11.4 ± 2.4%; elite = 10.5 ± 1.7%), hematocrit (non-elite = 50.2 ± 4.0%; elite = 51.0 ± 4.0%), CV (non-elite = 3.1 ± 0.4 m/s; elite = 3.0 ± 0.2 m/s), and ARC (non-elite = 129.6 ± 55.7 m; elite = 161.5 ± 61.0 m) showed no significant differences between the elite and non-elite teams, while the multivariate Partial Least Squares Discriminant Analysis (PLS-DA) model revealed a separation between the elite and non-elite athletes. Nineteen metabolites with importance for projection (VIP) >1.0 were annotated as belonging to the glycerolipid, sterol lipid, fatty acyl, flavonoid, and glycerophospholipid classes. Metabolites with a high relative abundance in the elite group were related in the literature to a better level of aerobic power, greater efficiency in the recovery process, and improvement of mood, immunity, decision making, and accuracy, in addition to acting in mitochondrial preservation and electron transport chain maintenance. In conclusion, although classical physical assessments were not able to distinguish the teams at different competitive levels, the metabolomics approach successfully indicated differences between the fasting metabolic profiles of elite and non-elite teams.
... Using data from the vertical location of the centre of masses for the EAB and the motorbike, the torque required to sustain the motorbike and the EAB was calculated at various inclinations (0-30 ). Breath-by-breath gas exchange variables were used to calculate energy expenditure, where carbohydrate and fat oxidation rates were calculated assuming non-protein metabolism (Kingsley et al. 2006) and equations derived by Peronnet and Massicotte (1991). In addition, metabolic equivalent (MET) values were calculated using a standardised formula (METs ¼ _ V O 2 in mL/kg/min divided by 3.5; Morris et al. 1993). ...
Electrically assisted bicycles (EABs) and motorbikes were compared in terms of energy expenditure, internal and external forces, and technique when delivering mail with different loads at different distances from the mailbox. Twenty-two postal workers performed two simulated postal tasks (foot placement [close vs. far] and delivery, and simulated mail delivery circuit) while carrying 0 and 32 kg. Independent of mail load, delivering mail with EABs was classified as moderate intensity and resulted in 33% higher energy expenditure when compared to motorbikes. Ground reaction forces were larger (7-25%) for EAB when compared to motorbike. Larger ground reaction forces were observed when both EABs and motorbikes were positioned further from the mailbox (5-23%). Using EABs during mail delivery has potential to result in numerous health benefits that are associated with moderate intensity physical activity, but can lead to larger external forces when compared to motorbikes.
PRACTITIONER SUMMARY: In order to compare electrically assisted bicycles (EAB) and motorbikes, postal workers performed simulated deliveries in the laboratory whilst measurements of energy expenditure, body loads and movement patters were undertaken. Body loads and energy expenditure were larger using EAB, which result in health benefits associated with moderate intensity exercise.
... However, an increased utilization of amino acids during physical activity augments their demand, and if this demand is not suited, induces fatigue, reducing performance. Serine supplementation in the form of phosphatidylserine increases exercise capacity during cycling trough modulating circulating cortisol and testosterone [56]. Arginine supplementation can extend the time to exhaustion during severe-intensity exercise. ...
Exercise is considered to be the best approach to improve quality of life, and together with a healthy and adequate dietary pattern, exercise represents the best strategy to reduce the risk of chronic metabolic and inflammatory diseases, such as those related to obesity. The regularity and intensity of exercise is modulated at the molecular level in the skeletal muscle by two protein kinases, the mechanistic target of rapamycin (mTOR) and AMP-activated protein kinase (AMPK), which act as sensors of external stimuli, showing the energy status of muscular fibers. The mTOR pathway is activated by insulin and amino acid availability, and its metabolic actions culminate in increased protein synthesis and reduced autophagy, leading to an increase in muscle mass. In contrast, AMPK activation induces a transcriptional program aimed to increase the mitochondrial content in skeletal muscle, transforming fast-twitch glycolytic fibers to slow-twitch oxidative fibers and increasing resistance to fatigue. In addition, inadequate exercise training induces imbalance in the immune response, generating excessive inflammation and/or immunosuppression. The purpose of this review is to summarize recent studies that provide insight into dietary protein interventions and/or amino acid supplementation that may improve outcomes after exercise by modulating 1) mTOR and AMPK activation during early exercise recovery, leading to increased muscle protein synthesis or increased oxidative capacity; 2) undesirable inflammatory responses; and 3) fibroblast growth factor 21 (FGF21) levels that may have relevant implications in skeletal muscle metabolism, particularly during the exercise recovery and performance of obese subjects.
... Energy expenditure was derived during the mail delivery circuit and 3-min stationary cycling from calculated carbohydrate and fat oxidation rates using indirect calorimetry assuming non-protein metabolism, as previously described (Kingsley et al., 2006) using equations derived by Peronnet and Massicotte (1991). ...
This study quantified the biomechanical (movements and forces) and physiological (energy expenditure) demands of postal delivery performed with electrically assisted bicycles (EABs). Ten postal workers and 10 recreational athletes performed three simulated postal tasks (simulated mail delivery circuit, delivery distance [close vs. far], and 3-min stationary cycling) while carrying 0, 16 and 32 kg. Physiological (energy expenditure) and biomechanical (internal and external forces and joint angles) responses were calculated. Energy expenditure (10–20%; p < 0.05) and power output (30–44%; p < 0.05) increased with increasing mail loads. Ground reaction force increased (∼10%) for the far delivery distance, but joint reaction forces were unchanged. Lower hip flexion (p < 0.01), less hip abduction (p < 0.01) and larger spine anterior flexion (p < 0.01) were observed for the far delivery distance. Joint forces were not affected by the mail load transported (0–32 kg) or distance from the mailbox (close vs far). EABs can provide a suitable transportation method to assist mail delivery in terms of energy expenditure reduction.
... Phosphatidylserine PtdSer comprises serine and two fatty acids Fig. 1A , and is the most abundant negatively charged phospholipid in eukaryotic membranes, mainly in the inner leaflet of the plasma membrane and in endocytic membranes 1,2 . PtdSer supplementation shows several health benefits, such as improvement of cognitive memory functions in middle-aged and elderly people 3 5 , reduction in stress-induced activation of the hypothalamopituitary-adrenal axis in healthy men 6 , suppression of attention-deficit hyperactivity disorder symptoms and shortterm auditory memory in children 7 , reduction in cortisol responses to physical exercise 6,8 , and improvement of exercise capacity in healthy young men 9 . ...
Phosphatidylserine (PtdSer) is mainly derived from the bovine brain cortex or soybean lecithin. We investigated macrophage uptake behavior and the anti-inflammatory response induced by liposomes containing bovine brain- (B-PSL) or soybean-derived PtdSer (S-PSL). The size of B-PSL and S-PSL was very similar. There were no significant differences in the uptake of B-PSL and S-PSL by Raw 264.7 macrophage cells. Addition of B-PSL or S-PSL decreased the production of the inflammatory cytokines, IL-1α, IL-6 and TNF-α, in lipopolysaccharide-treated Raw 264.7 cells, but there were no differences between them. These results suggest that S-PSL may be used as an anti-inflammatory agent.
... Supplementation with this CEN influences perceived fatigue during exercise [28]. In addition, phosphatidylserine supplementation can extend time to exhaustion in a long biking session in active males [29]. The effects on other types of exercise measures in other types of exercisers await further research. ...
Background:
Certain essential and conditionally essential nutrients (CENs) perform functions involved in aerobic exercise performance. However, increased intake of such nutrient combinations has not actually been shown to improve such performance.
Methods:
For 1 mo, aerobically fit, young adult women took either a combination of 3 mineral glycinate complexes (daily dose: 36 mg iron, 15 mg zinc, and 2 mg copper) + 2 CENs (daily dose: 2 g carnitine and 400 mg phosphatidylserine), or the same combination with generic mineral complexes, or placebo (n = 14/group). In Trial 1, before and after 1 mo, subjects were tested for 3 mile run time (primary outcome), followed by distance covered in 25 min on a stationary bike (secondary outcome), followed by a 90 s step test (secondary outcome). To test reproducibility of the run results, and to examine a lower dose of carnitine, a second trial was done. New subjects took either mineral glycinates + CENs (1 g carnitine) or placebo (n = 17/group); subjects were tested for pre- and post-treatment 3 mile run time (primary outcome).
Results:
In Trial 1, the mineral glycinates + CENs decreased 3 mile run time (25.6 ± 2.4 vs 26.5 ± 2.3 min, p < 0.05, paired t-test) increased stationary bike distance after 25 min (6.5 ± 0.6 vs 6.0 ± 0.8 miles, p < 0.05, paired t-test), and increased steps in the step test (43.8 ± 4.8 vs 40.3 ± 6.4 steps, p < 0.05, paired t-test). The placebo significantly affected only the biking distance, but it was less than for the glycinates-CENs treatment (0.2 ± 0.4. vs 0.5 ± 0.1 miles, p < 0.05, ANOVA + Tukey). The generic minerals + CENs only significantly affected the step test (44.1 ± 5.2 vs 41.0 ± 5.9 steps, p < 0.05, paired t-test) In Trial 2, 3 mile run time was decreased for the mineral glycinates + CENs (23.9 ± 3.1 vs 24.7 ± 2.5, p < 0.005, paired t-test), but not by the placebo. All changes for Test Formula II or III were high compared to placebo (1.9 to 4.9, Cohen's D), and high for Test Formula II vs I for running and biking (3.2 & 3.5, Cohen's D).
Conclusion:
In summary, a combination of certain mineral complexes plus two CENs improved aerobic exercise performance in fit young adult women.
... A decline of PS and other phospholipids in neuronal membranes has been associated with memory impairment and cognitive deficits whereas dietary PS and phospholipid supplements have prevented or reversed such deficits [70][71][72][73][74][75]. PS supplementation improved learning capacity and memory in rodents [76,77] and improved physical and mental performance such as long-term memory and recognition in elderly people with cognitive decline [73,[78][79][80], in stressed young adults [81], and in children with attention deficit hyperactivity disorder [82]. ...
Subjective memory complaints (SMCs) are common in older adults that can often predict further cognitive impairment. No proven effective agents are available for SMCs. The effect of BrainPower Advanced, a dietary supplement consisting of herbal extracts, nutrients, and vitamins, was evaluated in 98 volunteers with SMCs, averaging 67 years of age (47–88), in a randomized, double-blind, placebo-controlled trial. Subjective hypomnesis/memory loss (SML) and attention/concentration deficits (SAD) were evaluated before and after 12-week supplementation of BrainPower Advanced capsules (
n
=
47
) or placebo (
n
=
51
), using a 5-point memory questionnaire (1 = no/slight, 5 = severe). Objective memory function was evaluated using 3 subtests of visual/audio memory, abstraction, and memory recall that gave a combined total score. The BrainPower Advanced group had more cases of severe SML (severity
⩾
3) (44/47) and severe SAD (43/47) than the placebo group (39/51 and 37/51, < 0.05, < 0.05, resp.) before the treatment. BrainPower Advanced intervention, however, improved a greater proportion of the severe SML (29.5%)(13/44) (
P
<
0.01
) and SAD (34.9%)(15/43)(
P
<
0.01
) than placebo (5.1% (2/39) and 13.5% (5/37), resp.). Thus, 3-month BrainPower Advanced supplementation appears to be beneficial to older adults with SMCs.
... The first study reported no better cortisol concentrations, feelings of pain, and markers of muscular damage and peroxidation after an exhaustive run, even though the time-to-exhaustion increased in the PL arm [169]. In another study, Kingsley et al. [170] studied the ergogenic properties of PS and reported that its supplementation led to significant increases in training time, reaching 85% of VO 2max before exhaustion [171]. This study also reported direct effects on cortisol and adrenocorticotropin when PS was taken before biking. ...
Glycerophospholipids and sphingolipids participate in a variety of indispensable metabolic, neurological, and intracellular signaling processes. In this didactic paper we review the biological roles of phospholipids and try to unravel the precise nature of their putative healthful activities. We conclude that the biological actions of phospholipids activities potentially be nutraceutically exploited in the adjunct therapy of widely diffused pathologies such as neurodegeneration or the metabolic syndrome. As phospholipids can be recovered from inexpensive sources such as food processing by-products, ad-hoc investigation is warranted.
Copyright © 2015 Elsevier Ltd. All rights reserved.
... Moreover, administration of sphingosine-L-phosphate or sphingosine, a metabolite of sphingomyelin, improves muscle contractile force in mice (5). Phosphatidylserine, a milk phospholipid, increases exercise capacity in humans (21). More recently, the NAD precursor nicotinamide riboside, which is also found in milk, activates sirtuin activity, enhances mitochondrial gene expression, and protects against diet-induced obesity (2). ...
Milk fat globule membrane (MFGM) comprises carbohydrates, membrane-specific proteins, glycoproteins, phospholipids, and sphingolipids. We evaluated the effects of MFGM consumption over a 12-week period on endurance capacity and energy metabolism in BALB/c mice. Long-term MFGM intake combined with regular exercise improved endurance capacity, as evidenced by swimming time until fatigue, in a dose-dependent manner. The effect of dietary MFGM plus exercise was accompanied by higher oxygen consumption and lower respiratory quotient, as determined by indirect calorimetry. MFGM intake combined with exercise increased plasma levels of free fatty acids after swimming. After chronic intake of MFGM combined with exercise, the triglyceride content in the gastrocnemius muscle increased significantly. Mice given MFGM combined with exercise had higher mRNA levels of peroxisome proliferator-activated receptor-gamma coactivator 1α(Pgc1α) and CPT-1b in the soleus muscle at rest, suggesting that increased lipid metabolism in skeletal muscle contributes, in part, to improved endurance capacity. MFGM treatment with cyclic equibiaxial stretch consisting of 10% elongation at 0.5 Hz with 1 h on and 5 h off increased the Pgc1α mRNA expression of differentiating C2C12 myoblasts in a dose-dependent manner. Supplementation with sphingomyelin increased endurance capacity in mice and Pgc1α mRNA expression in the soleus muscle in vivo and in differentiating myoblasts in vitro. These results indicate that dietary MFGM combined with exercise improves endurance performance via increased lipid metabolism and that sphingomyelin may be one of the components responsible for the beneficial effects of dietary MFGM.
... Unlike the current data, some recent studies have previously demonstrated that prolonged exercise involving considerable eccentric muscular activity causes significant increases in LDL resistance to peroxidation in healthy males. 23,37 These equivocal results probably reflect increased mobilisation of antioxidant defences following prolonged exercise that leads to muscle damage and acute inflammation. ...
Many degenerative diseases are associated with increased oxidative stress. Creatine has the potential to act as an indirect and direct antioxidant; however, limited data exist to evaluate the antioxidant capabilities of creatine supplementation within in-vivo human systems. This study aimed to investigate the effects of oral creatine supplementation on markers of oxidative stress and antioxidant defenses following exhaustive cycling exercise. Following preliminary testing and two additional familiarization sessions, 18 active males repeated two exhaustive incremental cycling trials (T1 and T2) separated by exactly 7 days. The subjects were assigned, in a double-blind manner, to receive either 20 g of creatine (Cr) or a placebo (P) for the 5 days preceding T2. Breath-by-breath respiratory data and heart rate were continually recorded throughout the exercise protocol and blood samples were obtained at rest (preexercise), at the end of exercise (postexercise), and the day following exercise (post24 h). Serum hypdroperoxide concentrations were elevated at postexercise by 17 +/- 5% above pre-exercise values (P = 0.030). However, supplementation did not influence lipid peroxidation (serum hypdroperoxide concentrations), resistance of low density lipoprotein to oxidative stress (t1/2max LDL oxidation) and plasma concentrations of non-enzymatic antioxidants (retinol, alpha-carotene, beta-carotene, alpha-tocopherol, gamma-tocopherol, lycopene, and vitamin C). Heart rate and oxygen uptake responses to exercise were not affected by supplementation. These findings suggest that short-term creatine supplementation does not enhance non-enzymatic antioxidant defence or protect against lipid peroxidation induced by exhaustive cycling in healthy males.
... Studies using less than 800 mg of S-PS supplementation showed beneficial effects on performance and markers of muscle damage. 750 mg of S-PS resulted in an increased time to exhaustion during stage intermittent cycling exercise [12], and tended to improve sprint and exercise performances during exhaustive intermittent running when compared to placebo [13]. 600 mg and 300 mg S-PS significantly lowered creatine kinase levels 24-hours after a 90-min run [14]; however, none of the studies showed an effect on cortisol response, establishing the effective dose at 800 mg S-PS per day for short-term application (10–15 days). ...
Previous research has indicated that phosphatidylserine (PS) supplementation has the potential to attenuate the serum cortisol response to acute exercise stress. Equivocal findings suggest that this effect might be dose dependent. This study aimed to examine the influence of short-term supplementation with a moderate dose of PS (600 mg per day) on plasma concentrations of cortisol, lactate, growth hormone and testosterone before, during, and following moderate intensity exercise in healthy males.
10 healthy male subjects participated in the study. Each subject was assigned to ingest 600 mg PS or placebo per day for 10 days using a double-blind, placebo-controlled, crossover design. Serial venous blood samples were taken at rest, after a 15 minute moderate intensity exercise protocol on a cycle ergometer that consisted of five 3-minute incremental stages beginning at 65% and ending at 85% VO2 max, and during a 65 minute passive recovery. Plasma samples were assessed for cortisol, growth hormone, testosterone, lactate and testosterone to cortisol ratio for treatment (PS or placebo).
Mean peak cortisol concentrations and area under the curve (AUC) were lower following PS (39 +/- 1% and 35 +/- 0%, respectively) when compared to placebo (p < 0.05). PS increased AUC for testosterone to cortisol ratio (184 +/- 5%) when compared to placebo (p < 0.05). PS and placebo supplementation had no effect on lactate or growth hormone levels.
The findings suggest that PS is an effective supplement for combating exercise-induced stress and preventing the physiological deterioration that can accompany too much exercise. PS supplementation promotes a desired hormonal status for athletes by blunting increases in cortisol levels.
... Kingsley et al. [36] recently reported a double-blind, placebo-controlled clinical trial where fourteen active males completed staged intermittent exercise on three separate occasions, (a familiarization trial followed by two main trials that were separated by approximately 16 days). The staged intermittent protocol consisted of three 10-min stages of cycling at 45, 55 and 65% VO 2max followed by a final bout at 85% VO 2max that was continued until exhaustion. ...
Phospholipids are essential components of all biological membranes. Phosphatidylcholine (PC) and Phosphatidylserine (PS) are Phosphatidyl-phospholipids that are required for normal cellular structure and function. The participation in physical activity often challenges a variety of physiological systems; consequently, the ability to maintain normal cellular function during activity can determine sporting performance. The participation in prolonged intense exercise has been shown to reduce circulatory choline concentrations in some individuals. As choline is a pre-cursor to the neurotransmitter Acetylcholine, this finding has encouraged researchers to investigate the hypothesis that supplementation with PC (or choline salts) could enhance sporting performance. Although the available data that evaluates the effects of PC supplementation on performance are equivocal, acute oral supplementation with PC (~0.2 g PC per kg body mass) has been demonstrated to improve performance in a variety of sporting activities where exercise has depleted circulatory choline concentrations. Short term oral supplementation with soy-derived PS (S-PS) has been reported to attenuate circulating cortisol concentrations, improve perceived well-being, and reduce perceived muscle soreness after exercise. More recently, short term oral supplementation (750 mg per day of S-PS for 10 days) has been demonstrated to improve exercise capacity during high intensity cycling and tended to increase performance during intermittent running. Although more research is warranted to determine minimum dietary Phospholipid requirements for optimal sporting performance, these findings suggest that some participants might benefit from dietary interventions that increase the intakes of PC and PS.
Chronic fatigue and Immune Dysfunction Syndrome (CFIDS) is a heterogeneous disease that may be promoted by various environmental stressors, including viral infection, toxin uptake, and ionizing radiation exposure. Previous studies have identified mitochondrial dysfunction in CFIDS patients, including modulation of mitochondrial respiratory chain activity, deletions in the mitochondrial genome, and upregulation of reactive oxygen species (ROS). This paper focuses on radiation effects and hypothesizes that CFIDS is primarily caused by stressor-induced mitochondrial metabolic insufficiency, which results in decreased energy production and anabolic metabolites required for normal cellular metabolism. Furthermore, tissues neighbouring or distant from directly perturbed tissues compensate for this dysfunction, which causes symptoms associated with CFIDS. This hypothesis is justified by reviewing the links between radiation exposure and CFIDS, cancer, immune dysfunction, and induction of oxidative stress. Moreover, the relevance of mitochondria in cellular responses to radiation and metabolism are discussed and putative mitochondrial biomarkers for CFIDS are introduced. Implications for diagnosis are then described, including a potential urine assay and PCR test for mitochondrial genome mutations. Finally, future research needs are offered with an emphasis on where rapid progress may be made to assist the afflicted.
Like other glycerophospholipids, Phosphatidylserine (PS) exists as one of the components of the bilayer membrane of a cell. Though not as abundant as phosphatidylcholine (PC) and phosphatidylethanolamine (PE or cepharin), PS is one of the most important phospholipids, both from biological function and dietary nutrition points of view. PS is located asymmetrically in the cell membrane and mostly in the inner leaflet of the cell. Besides maintaining membrane integrity, it is also involved in various cell activities through binding to and activating on several classes of enzymes and supplying a negatively charged surface in order to recruit positively charged molecules such as proteins. As a member of the glycerophospholipid class, the PS molecule has a glycerol moiety esterified by fatty acids at the first and second positions of the glycerol molecule, and the head group at the third position is the amino acid serine esterified to phosphate. Therefore, it is negatively charged under physiological conditions, unlike PC and PE that are zwitterionic. This physical property is very important for PS as it lays the foundation for the biological functions of PS within the cell. In recent years, with the help of emerging technologies, elucidation of the biological function of PS has made great progress. This chapter focuses on the new findings about the functionality of this important phospholipid, including the authors' works, from a practical point of view.
Brain function is a rather emotional subject, much more than for example kidney or liver function. The reason is that we consider our brain as us and that we cannot separate ourselves from it. We hate to admit there is anything wrong with our brain and cognitive function because that is far too personal. But very often brain function deteriorates with age or under stressful conditions, even if - apart from that we are generally healthy. All our brain and body cells contain membrane structures, the master switch and work surface for most of the brain's metabolic processes. These membranes are predominantly made of a class of highly functional phospholipids. Intensive research over the last 30 years has demonstrated that the oral administration of j certain phospholipids have an attractive potential to improve brain performance in people of all ages. To date we have clinical data about three different phospholipids or phospholipid derivatives influencing mental performance, stress and mood: Phosphatidylcholine (PC) from soya Phosphatidylserine (PS) from soya (or fish) Glycero-phospho-choline (GPC) made from PC.
Fibromyalgia (FM) is an idiopathic disease characterized by widespread pain and a myriad of symptoms. Symptoms are diverse and include not only pain but also anxiety, depression, orthostatic intolerance, and cold intolerance. While the etiology of FM is not fully understood, data have suggested that FM may stem from dysfunction of the autonomic nervous system. This dysfunction has been reported at rest, and after a physiological stressor such as exercise. However, few studies have examined the responses during exercise. This novel approach may shed some new light on the effect of exercise in women with FM.
Phosphatidylserine (PtdSer) is a ubiquitous phospholipid species that is normally located within the inner leaflet of the cell membrane. PtdSer has been implicated in a myriad of membrane-related functions. As a cofactor for a variety of enzymes, PtdSer is thought to be important in cell excitability and communication. PtdSer has also been shown to regulate a variety of neuroendocrine responses that include the release of acetylcholine, dopamine and noradrenaline. Additionally, PtdSer has been extensively demonstrated to influence tissue responses to inflammation. Finally, PtdSer has the potential to act as an effective antioxidant, especially in response to iron-mediated oxidation.
The majority of the available research that has investigated the effects of PtdSer supplementation on humans has concentrated on memory and cognitive function; patients experiencing some degree of cognitive decline have traditionally been the main focus of investigation. Although investigators have administered PtdSer through intravenous and oral routes, oral supplementation has wider appeal. Indeed, PtdSer is commercially available as an oral supplement intended to improve cognitive function, with recommended doses usually ranging from 100 to 500 mg/day. The main sources that have been used to derive PtdSer for supplements are bovine-cortex (BC-PtdSer) and soy (S-PtdSer); however, due to the possibility of transferring infection through the consumption of prion contaminated brain, S-PtdSer is the preferred supplement for use in humans. Although the pharmacokinetics of PtdSer have not been fully elucidated, it is likely that oral supplementation leads to small but quantifiable increases in the PtdSer content within the cell membrane.
A small number of peer-reviewed full articles exist that investigate the effects of PtdSer supplementation in the exercising human. Early research indicated that oral supplementation with BC-PtdSer 800 mg/day moderated exercise-induced changes to the hypothalamo-pituitary-adrenal axis in untrained participants. Subsequently, this finding was extended to suggest that S-PtdSer 800 mg/day reduced the cortisol response to overtraining during weight training while improving feeling of well-being and decreasing perceived muscle soreness. However, equivocal findings from our laboratory might suggest that the dose required to undertake this neuroendocrine action may vary between participants.
Interestingly, recent findings demonstrating that short-term supplementation with S-PtdSer 750 mg/day improved exercise capacity during high-intensity cycling and tended to increase performance during intermittent running might suggest an innovative application for this supplement. With the findings from the existing body of literature in mind, this article focuses on the potential effects of PtdSer supplementation in humans during and following exercise.
This study investigated the effects of 750 mg of soybean-derived phosphatidylserine (S-PtdSer), administered daily for 7 d prior to a bout of eccentric exercise and for 2d following exercise, on delayed onset of muscle soreness and markers of muscle damage, inflammation, and oxidative stress that followed prolonged downhill running.
Following preliminary testing and a familiarization session, eight recreationally active males repeated an individualized downhill run at -16.5% for 51.0 +/- 1.5 min at 8.7 +/- 0.3 km x h(-1) on four occasions (trials 1-4). Trials 1 and 37 were presupplementation control trials. After trials 1 and 3 the subjects received, in a double-blind and crossover fashion, either S-PtdSer or a glucose polymer placebo. Trials 2 and 3 were separated by a 4-wk washout period. Venous blood, perceived soreness ratings, and feeling states were assessed prior to exercise, after exercise, and at 24 and 48 h after exercise during each trial.
Downhill running led to elevations in perceived soreness (P < 0.05), creatine kinase activities (P < 0.001), myoglobin concentrations (P < 0.001), interleukin-6 (IL-6) concentrations (P < 0.001), and lipid hydroperoxide concentrations (P < 0.01). However, supplementation did not significantly attenuate these responses.
These results suggest that supplementation with 750 mg x d(-1) S-PtdSer for 10 d does not afford additional protection against delayed onset of muscle soreness and markers of muscle damage, inflammation, and oxidative stress that follow prolonged downhill running.
The aim of this study was to investigate the effect of phosphatidylserine (PS) on cognition and cortical activity after mental stress. After familiarization, 16 healthy subjects completed cognitive tasks after induced stress in a test-re-test design (T1 and T2). Directly after T1, subjects were assigned double-blind to either PS or placebo groups followed by T2 after 42 days. At T1 and T2, cortical activity was measured at baseline and immediately after stress with cognitive tasks using electro-encephalography (EEG). EEG was recorded at 17 electrode positions and fast Fourier transforms (FFT) determined power at Theta, Alpha-1, Alpha-2, Beta-1 and Beta-2. Statistics were calculated using ANOVA (group x trial x time). The main finding of the study was that chronic supplementation of phosphatidylserine significantly decreases Beta-1 power in right hemispheric frontal brain regions (F8; P < 0.05) before and after induced stress. The results for Beta-1 power in the PS group were connected to a more relaxed state compared to the controls.
• Contemporary stable isotope methodology was applied in combination with muscle biopsy sampling to accurately quantify substrate utilisation and study the regulation of muscle fuel selection during exercise. • Eight cyclists were studied at rest and during three consecutive 30 min stages of exercise at intensities of 40, 55 and 75 % maximal workload (Wmax). A continuous infusion of [U-13C]palmitate and [6,6-2H2]glucose was administered to determine plasma free fatty acid (FFA) oxidation and estimate plasma glucose oxidation, respectively. Biopsy samples were collected before and after each exercise stage. • Muscle glycogen and plasma glucose oxidation rates increased with every increment in exercise intensity. Whole-body fat oxidation increased to 32 ± 2 kJ min−1 at 55 % Wmax, but declined at 75 % Wmax (19 ± 2 kJ min−1). This decline involved a decrease in the oxidation rate of both plasma FFA and triacylglycerol fat sources (sum of intramuscular plus lipoprotein-derived triacylglycerol), and was accompanied by increases in muscle pyruvate dehydrogenase complex activation and acetylation of the carnitine pool, resulting in a decline in muscle free carnitine concentration. • We conclude that the most likely mechanism for the reduction in fat oxidation during high-intensity exercise is a downregulation of carnitine palmitoyltransferase I, either by this marked decline in free carnitine availability or by a decrease in intracellular pH.
The effect of chronic administration of phosphatidylserine derived from brain cortex on the neuroendocrine responses to physical stress has been examined in a placebo-controlled study in 9 healthy men. Phosphatidylserine 800 mg/d for 10 days significantly blunted the ACTH and cortisol responses to physical exercise (P = 0.003 and P = 0.03, respectively), without affecting the rise in plasma GH and PRL. Physical exercise significantly increased the plasma lactate concentration both after placebo and phosphatidylserine. The results suggest that chronic oral administration of phosphatidylserine may counteract stress-induced activation of the hypothalamo-pituitary-adrenal axis in man.
The purpose of this paper is to point out some limits and inconsistencies in the table of nonprotein respiratory quotient that is universally used. This table, developed by Lusk in 1924, was derived from biochemical and physical data that are now outdated. A new table of nonprotein respiratory quotient, consistent with modern chemical and physical data, is proposed. The revised table is based on (a) the average composition of human triacylglycerol stores, (b) energy potential of fatty acids and glucose, and (c) the volumes occupied by one mole of oxygen or carbon dioxide (which are not ideal gases) under STPD conditions.
Recent work conducted by our group has expanded knowledge on some basic issues related to pulmonary and skeletal muscle O2 uptake (VO2) on-kinetics. We demonstrated that, in exercising humans during transitions from unloaded pedaling to loaded pedaling below the ventilatory threshold, alveolar VO2 on-kinetics can be taken as a rather close approximation of skeletal muscle VO2 on-kinetics. Experiments conducted on the isolated in situ dog gastrocnemius preparation have shown that, during transitions from rest to contractions corresponding to approximately 70% of the muscle peak VO2, convective O2 delivery to muscle, intramuscular blood flow (Q) versus VO2 maldistribution, and peripheral O2 diffusion are not limiting factors for skeletal muscle VO2 on-kinetics. The latter, therefore, appears to be mainly determined by an intrinsic inertia of skeletal muscle oxidative metabolism, possibly related to acetyl group availability within mitochondria, to regulatory effects on intracellular respiration related to phosphocreatine splitting, and/or to other still not precisely identified control mechanism(s). Evidence from the literature suggests that the limiting factors for skeletal muscle VO2 on-kinetics may vary according to the intensity of muscular contractions or of exercise.
Phosphatidylserine (PS) is a phospholipid which has been claimed to enhance neuronal membrane function, and can be derived from several sources. Earlier studies used brain cortex derived PS, of which the human tolerability of 300mg daily in 130 patients has been shown. The human tolerability of PS derived from soybean has not been reported, although it is widely sold as a nutritional supplement which may improve cognitive function in the elderly. We report the results of a study of the safety of two dosages of soy-phosphatidylserine (S-PS) in elderly. Subjects were 120 elderly of both sexes who fulfilled the more stringent criteria for age-associated memory impairment; some also fulfilled the criteria for age-associated cognitive decline. Subjects were allocated at random to one of the three treatment groups: placebo, 300 or 600 mg S-PS daily. Standard biochemical and hematological safety parameters, blood pressure, heart rate and adverse events were assessed at baseline, after 6 and 12 weeks of treatment. No significant differences were found in any of the outcome variables between the treatment groups after Bonferonni-Holme correction. In conclusion, soy derived PS is a safe nutritional supplement for older persons if taken up to a dosage of 200 mg three times daily.
This study examined the oxygen uptake (VO(2)) and heart rate (HR) kinetics during arm cranking and leg cycling at work rates above the anaerobic threshold (AT). Ten untrained male subjects [21.6 (1.3) years] completed two 7 min 15 s constant-load arm cranking and two leg cycling tests at a power output halfway between the mode-specific AT and peak VO(2). The time constants for phase II VO(2) (tau) and HR (tau) kinetics were determined by fitting a monoexponential curve from the end of phase I until 3 min of exercise. VO(2) tau and HR tau values were significantly (P < 0.001) slower in arm cranking [VO(2) tau = 66.4 (3.0) s; HR tau = 74.7 (4.4) s] than in leg cycling [VO(2) tau = 42.0 (1.9) s; HR tau = 55.6 (3.5) s]. The VO(2) slow component (VO(2SC)) accounted for a significantly (P < 0.001) greater percentage of the total exercise response during arm cranking [23.8 (1.6)%] than during leg cycling [14.2 (1.5)%]. The greater relative VO(2SC) and the slower VO(2) tau with arm exercise are consistent with a greater recruitment of metabolically inefficient type II muscle fibres during arm cranking than during leg cycling.
A balanced order, double-blind, cross-over design study, measured the effects of 800 mg soybean-derived phosphatidylserine (PS) or placebo (C), administered daily during 2-week intense weight training, on cortisol (CT), ACTH, testosterone (TS), luteinising hormone (LH), creatine kinase (CK) activity, subjective well-being (WB) and muscle soreness (MS) in 11 trained males. Subjects did 5 sets of 10 repetitions for 13 exercises, 4 times a week, for two 2-week periods separated by a 3-week recovery. Resting morning venous blood was sampled 6 times during each 2-week period (T1-T6) and 15 min following the 8th training sessions (T7). WB and MS were estimated using 10-point scales. CT was similar between treatments in T1-T6. CT decreased between T6 and the post-exercise T7 in PS (15.6±1.7 to 10.0±0.9 μg/dl, P<0.05) but not in C. ACTH did not change in PS in T1-T7 but increased in C between T4 (40.6±5.1 pg/ml) and T5 (62.2±10.5 pg/ml), T6 (59.2±7.7 pg/ml), and T7 (63.7+6.1 pg/ml). TS increased in PS between T1 (3.3±0.3 ng/ml) and T3 (4.4±0.5 ng/ml) and fell in both treatments between T3 and T7 (3.3±0.3 ng/ml, PS; 3.3±0.4, C). LH increased significantly between T1 (1.5±0.1 mIU/ml) and T6 (2.2±0.3 mIU/ml) in PS but did not change in C. WB was greater in P than C in T2-T6. In C, WB at T3 was markedly depressed (4.9±0.8). MS increased in both treatments and was greater in C than PS at T2 (2.9±0.4, PS; 4.7±0.7 C) and T5 (2.0±0.5, PS; 3.6±0.9 C). Cortisol decreased in PS after exercise, possibly by depressing ACTH and might have attenuated the negative effects of intense weight training on perception of well-being and muscle soreness.
This double- blind study assesses the therapeutic efficacy and the safety of oral treatment with phosphatidylserine (BC- PS) vs placebo (300 mg/day for 6 months) in a group of geriatric patients with cognitive impairment. A total of 494 elderly patients (age between 65 and 93 years), with moderate to severe cognitive decline, according to the Mini Mental State Examination and Global DeteriorationScale, were recruited in 23 Geriatric or General Medicine Units in Northeastern Italy. Sixty- nine patients dropped out within the 6- month trial period. Patients were examined just before starting therapy, and 3 and 6 months thereafter. The efficacy of treatment compared to placebo was measured on the basis of changes occurring in behavior and cognitive performance using the Plutchik Geriatric Rating Scale and the Buschke Selective Reminding Test. Statistically significant improvements in the phosphatidylserine- treated group compared to placebo were observed both in terms of behavioral and cognitive parameters. In addition, clinical evaluation and laboratory tests demonstrated that BC- PS was well tolerated. These results are clinically important since the patients were representative of the geriatric population commonly met in clinical practice. (Aging Clin. Exp. Res. 5: 123- 133, 1993).
Describes the development and validation of a measure designed to assess feeling states that occur in conjunction with acute bouts of physical activity, the Exercise-Induced Feeling Inventory (EFI). The EFI consists of 12 items that capture 4 distinct feeling states: revitalization, tranquility, positive engagement, and physical exhaustion. The multidimensional structure of the EFI is supported by confirmatory factor analysis. The subscales have good internal consistency, share expected variance with related constructs, are sensitive to exercise interventions, and appear responsive to the different social contexts in which activity may occur. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Objective: To investigate the effects of cognitive strategies, exercise setting, and participants’ gender on performance, perceived exertion, affect, and satisfaction in recreational runners.Methods: A 3×2×2 mixed experimental design with Exercise Setting (i.e., treadmill, indoor track, and outdoor route) as a within-groups independent variable and Cognitive Strategy (association vs. dissociation) and Gender as between-groups factors. Dependent measures were performance time, Ratings of Perceived Exertion (RPE), Exercise-Induced Feeling Inventory (EFI) scores, and course satisfaction following a 5 km run.Results and conclusions: Strong effects were found for Exercise Setting. The treadmill setting was rated as least satisfying, while resulting in the highest RPE and slowest performance time. Alternately, the outdoor route resulted in the highest levels of positive engagement, revitalization, tranquillity, and course satisfaction, while also yielding the lowest levels of physical exhaustion and RPE. There were no overall differences in RPE or course satisfaction between the Cognitive Strategies; however, the association group ran faster and experienced lower levels of tranquillity than the dissociation group. The only statistically significant difference found for Gender was that males ran faster than females.
A Mg2(+)-ATPase-enriched fraction was obtained from solubilized human erythrocyte membranes by ammonium sulphate precipitation and anion-exchange chromatography. The solubilized enzyme, of apparent molecular weight 120 kDa, requires phosphatidylserine to be fully active. Phosphatidylethanolamine but not other anionic phospholipids can only partially restore the activity. The Mg-ATPase has a low affinity for Mg2(+)-ATP and is inhibited by fluoride, vanadate, vanadyl and calcium ions. From these characteristics, we infer that this Mg2(+)-ATPase is the same protein as the aminophospholipid translocase which regulates the membrane phospholipid transverse distribution in human erythrocytes by actively transporting aminophospholipids from the outer to the inner monolayer.
The activity of brain cortex-derived phosphatidylserine (BC-PS) on the neuroendocrine and neurovegetative responses to physical stress was tested in 8 healthy men who underwent three experiments with a bicycle ergometer. According to a double-blind design, before starting the exercise, each subject received intravenously, within 10 min, 50 or 75 mg of BC-PS or a volume-matched placebo diluted in 100 ml of saline. Blood samples were collected before and after the exercise for plasma epinephrine (E), norepinephrine (NE), dopamine (DA), adrenocorticotropin (ACTH), cortisol, growth hormone (GH), prolactin (PRL) and glucose determinations. Blood pressure and heart rate were also recorded. Physical stress induced a clear-cut increase in plasma E, NE, ACTH, cortisol, GH and PRL, whereas no significant change was observed in plasma DA and glucose. Pretreatment with both 50 and 75 mg BC-PS significantly blunted the ACTH and cortisol responses to physical stress.
1. The effects of phosphate and protons on the mechanics and energetics of muscle contraction have been investigated using glycerinated rabbit psoas muscle. 2. Fibres were fully activated by addition of Ca2+ (pCa 4-5) at 10 degrees C. The velocities of contraction were measured in isotonic load clamps, and the velocities of unloaded fibres were measured by applying a series of step changes in fibre length. Fibre ATPase activity was monitored using an enzyme system to couple ADP production to reduced nicotinamide-adenine dinucleotide (NADH) and measuring the depletion of NADH by optical density. 3. At pH 7.0 and 3 mM-phosphate, isometric tension (P0) was 13.2 +/- 0.9 N/cm (mean +/- S.E.M., n = 10 observations), the maximum contraction velocity (Vmax) was 1.63 +/- 0.05 lengths/s (n = 5) and the ATPase activity was 1.27 +/- 0.12 s-1 myosin head-1 (n = 35). Increasing phosphate from 3 to 20 mM at pH 7.0 does not affect Vmax, causes a small decrease in the ATPase activity (15-20%) and decreases P0 by approximately 20%. Changing pH from 7 to 6 at 3 mM-phosphate decreases P0 by 45% and both Vmax and ATPase activity by 25-30%. The effects of changing both pH and phosphate were approximately additive for all parameters measured. The inhibition of these parameters by low pH and high concentration of phosphate was reversible. 4. The force-velocity relation was fitted by the Hill equation using a non-linear least-squares method. The value of the parameter which describes the curvature, a/P0, was 0.20. The curvature of the force-velocity relation was not changed by addition of phosphate or by changes in pH. 5. These data provide information on both the kinetics of the actomyosin interaction and on the process of muscle fatigue. The data are consistent with models of cross-bridge kinetics in which phosphate is released within the powerstroke in a step involving a rapid equilibrium between states. The inhibition by protons is more complex, and may involve less specific effects on protein structure. 6. During moderate fatigue of living skeletal muscle, MgATP concentration is known to remain approximately constant at 4 mM, phosphate to increase from 3 to 20 mM, and protons from 0.1 to 1 microM. The data suggest that much of the inhibition of P0 observed during moderate fatigue can be explained by the increased levels of phosphate and protons, and that much of the inhibition of fibre Vmax and ATPase activity can be explained by the increase in protons.
Amino acids stimulated the (Na+ + K+)-dependent ATPase activity of a rabbit kidney preparation without affecting the Mg2+-ATPase activity; the most effective was histidine, producing a 2-fold increase in activity. Similar stimulation was produced by the well-known chelators EDTA, EGTA, and 8-hydroxyquinoline, and by the chelating phospholipid phosphatidylserine. In the presence of maximally effective concentrations of one agent, the other agents were unable to produce additional stimulation. It is suggested that the amino acids, phosphatidylserine, and the conventional chelators all stimulate the ATPase by a common mechanism: the removal of inhibitory trace metal (s). From measurements of the metal content of the enzyme preparation and experiments with extracted reagents it was concluded that the chelatable inhibitor was in the reagents used in the incubation medium rather than being endogenous to the enzyme; attempts to identify the inhibitor (s) were unsuccessful. The chelators also stimulated the K+-dependent phosphatase activity in the preparation but had no major effect on Na+-dependent incorporation of 32P from [32P]ATP. On monovalent cation activation the chelators appeared to relieve an uncompetitive inhibition of Na32 activation and a noncompetitive inhibition of K32 activation, also suggesting an action of the chelatable inhibitor on the later stages of the ATPase reaction sequence.
Observations on hematocrit (Hct) and hemoglobin (Hb) were made in 6 men before and after running long enough to cause a 4% decrease in body weight. Subscripts B and A were used to denote before dehydration and after dehydration, respectively. Relations were derived between BV(b), BV(a), HB(b), Hb(a), Hct(b), and Hct(a) with which the percentage decreases in BV, CV, and PV can be calculated, as well as the concentration of hemoglobin in red cells, g/100 ml-1 (MCHC). When subjects reach the same level of dehydration the water loss from the various body compartments may vary reflecting the difference in salt losses in sweat. Changes in PV calculated from the increase in plasma protein concentration averaged -7.5% compared with -12.2% calculated from changes in Hb and Hct. The difference could be accounted for by a loss of 6% plasma protein from the circulation.
Phosphatidylserine (PtdSer) incubated with synaptosomal plasma membranes (SPM) of dog brain is incorporated into SPM in proportion to its concentration in the incubation medium. Low PtdSer concentrations progressively activated the SPM-associated (Na+ + K+)-stimulated ATPase and acetylcholinesterase. Increasing the PtdSer concentration above that which maximally stimulated the enzyme activities effected a progressive inhibition with respect to maximal stimulation. Arrhenius plots of (Na+ + K+ + Mg2+)-dependent ATPase and 5'-nucleotidase revealed a clear break at 23-24 degrees C for both enzymes in SPM untreated with PtdSer (controls), whereas a linear relation was obtained for SPM treated with PtdSer. Changes in the allosteric properties of (Na+ + K+)-stimulated ATPase by fluoride (F-) and/or of 5'-nucleotidase by concanavalin A (i.e. changes of Hill coefficients) indicate that PtdSer increases the membrane fluidity. These results suggest that modifications of lipid-protein interactions in SPM induced by PtdSer may have implications in the physiological processes in the central nervous system.
The ether phospholipid composition of various tissues (brain, heart, lung, liver, kidney, testis, erythrocytes and plasma) has been investigated in human, rat and guinea pig, using a new method of determination (El Tamer, A., Record, M., Fauvel, J., Chap, H. and Douste-Blazy, L. (1984) Biochim. Biophys. Acta 793, 213-220). This is based on the selective removal of diacyl phospholipid species by phospholipase A1 degradation followed by acidolysis of the plasmalogens. Our results fit rather well with other literature data available for human and rat tissues, illustrating the good reliability of the method. Among various differences noted between the three mammalian species, guinea pig is characterized by a relatively higher content of 1-alkyl-2-acyl-sn-glycero-3-phosphocholine (alkylacyl-GPC) and of ethanolamine plasmalogens in blood plasma. Alkylacyl-GPC, a putative precursor of platelet activating factor (PAF-acether or 1-alkyl-2-acetyl-GPC), is also more abundant in guinea pig lung and in human kidney. This study also revealed a striking parallelism between the tissue content of alkylacyl-GPC and alkylacyl-GPE (1-alkyl-2-acyl-sn-glycero-3-phosphoethanolamine). This new observation is discussed in relation to a possible metabolic link between these two phospholipids.
To determine the precise nonsteady-state characteristics of ventilation (VE), O2 uptake (VO2), and CO2 output (VCO2) during moderate-intensity exercise, six subjects each underwent eight repetitions of 100-W constant-load cycling. The tests were preceded either by rest or unloaded cycling ("0" W). An early component of VE, VO2, and VCO2 responses, which was obscured on any single test by the breath-to-breath fluctuations, became apparent when the several repetitions were averaged. These early responses were abrupt when the work was instituted from rest but were much slower and smaller from the 0-W base line and corresponded to the phase of cardiodynamic gas exchange. Some 20 s after the onset of the work a further monoexponential increase to steady state occurred in all three variables, the time constants of which did not differ between the two types of test. Consequently, the exponential behavior of VE, VO2, and VCO2 in response to moderate exercise is best described by a model that incorporates only the second phase of the response.
Marked changes were observed in the lipid composition of highly purified plasma membranes isolated from the hearts of rats subjected to daily treadmill running. Compared to sedentary controls, sarcolemmal content of total phospholipid and phosphatidylserine in the trained group was increased 23 and 50 percent, respectively. This observation suggests a mechanism by which cardiac contractility may be enhanced by exercise.
This double-blind study assesses the therapeutic efficacy and the safety of oral treatment with phosphatidylserine (BC-PS) vs placebo (300 mg/day for 6 months) in a group of geriatric patients with cognitive impairment. A total of 494 elderly patients (age between 65 and 93 years), with moderate to severe cognitive decline, according to the Mini Mental State Examination and Global Deterioration Scale, were recruited in 23 Geriatric or General Medicine Units in Northeastern Italy. Sixty-nine patients dropped out within the 6-month trial period. Patients were examined just before starting therapy, and 3 and 6 months thereafter. The efficacy of treatment compared to placebo was measured on the basis of changes occurring in behavior and cognitive performance using the Plutchik Geriatric Rating Scale and the Buschke Selective Reminding Test. Statistically significant improvements in the phosphatidylserine-treated group compared to placebo were observed both in terms of behavioral and cognitive parameters. In addition, clinical evaluation and laboratory tests demonstrated that BC-PS was well tolerated. These results are clinically important since the patients were representative of the geriatric population commonly met in clinical practice.
Protein kinases play important roles in intracellular signalling pathways in probably all cells. In the heart, they are involved in the regulation of ion handling, contractility, fuel metabolism and growth. In this review, we discuss the consequences of activation of protein kinases known to be expressed in the heart. We concentrate principally on the following: cyclic AMP-dependent protein kinase, protein kinase C, mitogen-activated protein kinase, Ca2+/calmodulin-dependent protein kinases and pyruvate dehydrogenase kinase.
The purpose of this study was to estimate the relative contributions of central and peripheral factors to the development of human muscle fatigue. Nine healthy subjects [five male, four female; age = 30 (2) years, mean (SE)] sustained a maximum voluntary isometric contraction (MVC) of the ankle dorsiflexor muscles for 4 min. Fatigue was quantitated as the fall in MVC. Three measures of central activation and one measure of peripheral activation (compound muscle action potential, CMAP) were made using electromyography (EMG) and electrical stimulation. Measures of intramuscular metabolism were made using magnetic resonance spectroscopy. After exercise, MVC and electrically stimulated tetanic contraction (50 Hz, 500 ms) forces were 22.2 (3.7)% and 37.3 (7.1)% of pre-exercise values, respectively. The measures of central activation suggested some central fatigue during exercise: (1) the central activation ratio [MVC/(MVC + superimposed tetanic force)] fell from 0.94 (0.03) to 0.78 (0.09), (2) the MVC/tetanic force ratio fell from 2.3 (0.7) to 1.3 (0.7), and (3) the integral of the EMG (iEMG) signal decreased to 72.6 (9.1)% of the initial value, while the CMAP amplitude was unchanged. Intramuscular pH was associated by regression with the decline in MVC force (and therefore fatigue) and iEMG. The results indicate that central factors, which were not associated with altered peripheral excitability, contributed approximately 20% to the muscle fatigue developed, with the remainder being attributable to intramuscular (i.e., metabolic) factors. The association between pH and iEMG is consistent with proton concentration as a feedback mechanism for central motor drive during maximal effort.
There are various clinical and non-clinical studies that have indicated that phosphatidylserine (PS) treatment can improve cognitive functions in humans and other animals. However, treatment with PS derived from bovine cortex is not desirable because of possible transfer of infectious diseases. The present study investigated the cognition-enhancing properties of different types of PS in rats. Seventeen-month-old male Fischer 344 rats were treated daily with a dose of 15 mg/kg of PS derived from bovine cortex (BC-PS), soybean (S-PS), egg (E-PS), or vehicle (n = 9 for each group). The effects of treatment were evaluated in three different behavioral tests. An open field test was conducted to examine the effects of treatment on psychomotor behavior. Two other tests (Morris water escape task and two-way active avoidance) assessed treatment effects on the cognitive performance of rats. Treatment with the different forms of PS did not affect the psychomotor or spatial discrimination performance of the rats. In accordance with previous studies, the cognition-enhancing effects of BC-PS were observed in the two-way active avoidance task. It appeared that the cognition-enhancing effects of S-PS were not different from those of BC-PS. The performance of rats treated with E-PS did not deviate from that of vehicle-treated rats. On the basis of the present study, it was concluded that S-PS, but not E-PS, may have comparable effects on cognition when compared with BC-PS.
The ATP turnover rate during constant-load exercise is often estimated from the initial rate of change of phosphocreatine concentration ([PCr]) using 31P-magnetic resonance spectroscopy (MRS). However, the phase and amplitude characteristics of the sample-to-sample fluctuations can markedly influence this estimation (as well as that for the time constant (tau) of the [PCr] change) and confound its physiological interpretation especially for small amplitude responses. This influence was investigated in six healthy males who performed repeated constant-load quadriceps exercise of a moderate intensity in a whole-body MRS system. A transmit- receive surface coil was placed under the right quadriceps, allowing determination of intramuscular [PCr]; pulmonary oxygen uptake (VO2) was simultaneously determined, breath-by-breath, using a mass spectrometer and a turbine volume measuring module. The probability density functions (PDF) of [PCr] and VO2 fluctuations were determined for each test during the steady states of rest and exercise and the PDF was then fitted to a Gaussian function. The standard deviation of the [PCr] and VO2 fluctuations at rest and during exercise (sr and sw, respectively) and the peak centres of the distributions (xc(r) and xc(w)) were determined, as were the skewness (gamma1) and kurtosis (gamma2) coefficients. There was no difference between sr and sw for [PCr] relative to the resting control baseline (s(r) = 1.554 %delta (s.d. = 0.44), s(w) = 1.514 %delta (s.d. = 0.35)) or the PDF peak centres (xc(r) = -0.013 %delta (s.d. = 0.09), xc(w) -0.197 %delta (s.d. = 0.18)). The standard deviation and peak centre of the 'noise' in VO2 also did not vary between rest and exercise (sr = 0.0427 l min(-1) (s.d. = 0.0104), s(w) = 0.0640 l min(-1) (s.d. = 0.0292); xc(r) = -0.0051 l min(-1) (s.d. = 0.0069), xc(w) 0.0022 l min(-1) (s.d. = 0.0034)). Our results demonstrate that the intersample 'noise' associated with [PCr] determination by 31P-MRS may be characterised as a stochastic Gaussian process that is uncorrelated with work rate, as previously described for VO2. This 'noise' can significantly affect the estimation of tau[PCr] and especially the initial rate of change of [PCr], i.e. the fluctuations can lead to variations in estimation of the initial rate of change of [PCr] of more than twofold, if the inherent 'noise' is not accounted for. This 'error' may be significantly reduced in such cases if the initial rate of change is estimated from the time constant and amplitude of the response.
1. The maximal oxygen uptake (V(O(2),peak)) during dynamic muscular exercise is commonly taken as a crucial determinant of the ability to sustain high-intensity exercise. Considerably less attention, however, has been given to the rate at which V(O(2)) increases to attain this maximum (or to its submaximal requirement), and even less to the kinetic features of the response following exercise. 2. Six, healthy, male volunteers (aged 22 to 58 years), each performed 13 exercise tests: initial ramp-incremental cycle ergometry to the limit of tolerance and subsequently, on different days, three bouts of square-wave exercise each at moderate, heavy, very heavy and severe intensities. Pulmonary gas exchange variables were determined breath by breath throughout exercise and recovery from the continuous monitoring of respired volumes (turbine) and gas concentrations (mass spectrometer). 3. For moderate exercise, the V(O(2)) kinetics were well described by a simple mono-exponential function, following a short cardiodynamic phase, with the on- and off-transients having similar time constants (tau(1)); i.e. tau(1,on) averaged 33 +/- 16 s (+/- S.D.) and tau(1,off) 29 +/- 6 s. 4. The on-transient V(O(2)) kinetics were more complex for heavy exercise. The inclusion of a second slow and delayed exponential component provided an adequate description of the response; i.e. tau(1,on) = 32 +/- 17 s and tau(2,on) = 170 +/- 49 s. The off-transient V(O(2)) kinetics, however, remained mono-exponential (tau(1,off) = 42 +/- 11 s). 5. For very heavy exercise, the on-transient V(O(2)) kinetics were also well described by a double exponential function (tau(1,on) = 34 +/- 11 s and tau(2,on) = 163 +/- 46 s). However, a double exponential, with no delay, was required to characterise the off-transient kinetics (i.e. tau(1,off) = 33 +/- 5 s and tau(2,off) = 460 +/- 123 s). 6. At the highest intensity (severe), the on-transient V(O(2)) kinetics reverted to a mono-exponential profile (tau(1,on) = 34 +/- 7 s), while the off-transient kinetics retained a two-component form (tau(1,off) = 35 +/- 11 s and tau(2,off) = 539 +/- 379 s). 7. We therefore conclude that the kinetics of V(O(2)) during dynamic muscular exercise are strikingly influenced by the exercise intensity, both with respect to model order and to dynamic asymmetries between the on- and off-transient responses.
There have been previous reports that supplements of phosphatidylserine (PS) blunted the release of cortisol in response to exercise stress and that it improved mood. The present study extended these observations by considering whether PS supplementation influenced subjective feelings of stress and the change in heart rate when a stressful mental arithmetic task was performed. In young adults, with neuroticism scores above rather than below the median, the taking of 300mg PS each day for a month was associated with feeling less stressed and having a better mood. The study for the first time reports an improvement in mood following PS supplementation in a sub-group of young healthy adults.
1. Repeated activity of skeletal muscle causes a variety of changes in its properties: muscles become weaker with intense use (fatigue), may feel sore and weak after repeated contractions involving stretch and can degenerate in some disease conditions. The present review considers the role of early ionic changes in the development of each of these conditions.
2. Single fibre preparations of mouse muscle were used to measure ionic changes following activity induced changes in function. Single fibres were dissected with intact tendons and stimulated to produce force. Fluorescent indicators were microinjected into the fibres to allow simultaneous ionic measurements with determination of mechanical performance.
3. One theory to explain muscle fatigue is that fatigue is caused by the accumulation of lactic acid, producing an intracellular acidosis that inhibits the myofibrillar proteins. In contrast, we found that during repeated tetani there was little or no pH change, but that failure of calcium release was a major contributor to fatigue. Currently, it is proposed that precipitation of calcium and phosphate in the sarcoplasmic reticulum contributes to the failure of calcium release.
4. Muscles can be used to shorten and produce force or they can be used to de-accelerate loads (stretched or eccentric contractions). One day after intense exercise involving stretched contractions, muscles are weak, sore and tender, and this damage can take a week to recover. In this condition, sarcomeres are disorganized and there are increases in resting intracellular Ca2+ and Na+. Recently, we demonstrated that the elevation of Na+ occurs through a stretch-activated channel that can be blocked by either gadolinium or streptomycin. Preventing the increase in [Na+]i with gadolinium also prevented part of the muscle weakness after stretched contractions.
5. Duchenne muscular dystrophy is a lethal degenerative disease of muscles in which the protein dystrophin is absent. Dystrophic muscles are more susceptible to stretch-induced muscle damage and the stretch-activated channel seems to be one pathway for the increases in intracellular Ca2+ and Na+ that are a feature of this disease. We have shown recently that blockers of the stretch-activated channel can minimize some of the short-term damage in muscles from the mdx mouse, which also lacks dystrophin. Currently, we are testing whether blockers of the stretch-activated channels given systemically to mdx mice can protect against some features of the disease.
The primary effect of ethanol is on the central nervous system. However, the molecular mechanisms responsible for the physiological symptoms of ethanol intoxication are still unknown. Low concentrations of ethanol were observed to stimulate the activity of the calcium pump from reconstituted synaptosomal plasma membrane Ca2+ -ATPase (PMCA), and ethanol inhibited Ca2+ -ATPase activity at concentrations above 5%. The greatest stimulating effect was obtained with 5% (v/v) ethanol and was lipid-dependent, being 74% when the protein had been reconstituted in phosphatidylcholine (PC) and less when the reconstituted protein had previously been activated by calmodulin or after removal of a 9-kDa autoinhibitory site by controlled trypsinization. Stimulation of the pump by ethanol was lower for the native or trypsin-digested protein in the presence of phosphatidylserine than in PC. These results suggest a direct ethanol-protein interaction, because the activating effect depended on the state of Ca2+ -ATPase (native or truncated, or in presence of calmodulin). The activating mechanism of ethanol may involve opening an autoinhibitory domain located close to the calmodulin binding domain.
Table of nonprotein respiratory quotient: an update.
- Peronnet
PERONNET, F., and D. MASSICOTTE. Table of nonprotein respiratory
quotient: an update. Can. J. Sport Sci. 16:23-29, 1991.
Textbook of Work Physiology, Physiological Bases of Exercise, Third Edition. McGraw-Hill International Editions
- P.-O Åstrand
- K Rodahl
ÅSTRAND, P.-O., and K. RODAHL. Textbook of Work Physiology,
Physiological Bases of Exercise, Third Edition. McGraw-Hill International Editions, 1986, pp. 556 -562.