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Resting hormonal and cardiovascular responses to short term creatine supplementation and resistance exercises
Abstract
Introduction: The purpose of this study was to examine the effects of 3, 5 and 7 days of creatine loading coupled with resistance exercise on resting testosterone and cortisol concentrations, systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate and rate pressure product (RPP). These measures were compared to those in placebo group. Summary of facts: Twenty active males were randomly assigned to either a creatine group (Cr) or placebo group (Pl). Participants performed resistance exercises at day 3, 5, and 7; and also tested at day 4, 6, and 8. Subjects of the Cr group showed significant increases in testosterone concentrations and decreases in cortisol concentrations, in comparison with Pl and baseline, after 5 and 7 days of Cr loading (P< 0.05). There were no significant changes in heart rate, SBP, DBP, MAP, and RPP for both groups at all times (P > 0.05). Conclusion: Results of the present study suggest that more than 5 days of creatine supplementation, associated with resistance exercises is sufficient for increasing testosterone concentrations and decrement in cortisol concentrations.
... Additionally, de Franca et al. [19] stated that Cr-HCl and CrM improved muscle strength after four weeks of RT, but only Cr-HCl changed body composition in recreational weightlifters [19]. In addition, Arazi et al. showed that acute CrM supplementation and RT positively affected testosterone and cortisol concentrations [20]. ...
... Moreover, Tayebi et al. stated that Cr-HCl supplementation (3 gr) for two weeks caused significant changes in soldiers' testosterone and cortisol levels [36]. Regarding the effects of CrM supplementation, the results of Arazi et al. showed that CrM supplementation (4×5 gr.d -1 ) for more than five days along with RT (3×10 rep of 9 exercises, 75-85 % 1RM) was sufficient to increase testosterone concentration and decrease cortisol concentration [20]. Burke et al. [8] showed a significant increase in intramuscular IGF-1 concentration in creatinereceiving athletes (0.25 g.kg dry mass in 7 days and 0.06 g.kg dry mass in 49 days) after an 8-week RT program. ...
... In addition, the increase in lean mass following creatine supplementation has been attributed, at least in part, to water retention in muscle tissue [51]. In general, studies on creatine supplementation have reported an increase in intracellular volume without changes in extracellular volume [20,37], possibly due to the high osmotic load associated with increased creatine and Na + in the cytosol. Indeed, cell swelling has been characterized as an anabolic signal [6], which can trigger the activation of osmotic molecules as G protein-coupled receptors in the mitogen-activated protein kinase (MAPK) and sphingosine kinase 1 (SPHK1) pathways stimulate and create positive feedback [37]. ...
The purpose of this study was to determine the effects of resistance training (RT) alongside creatine-hydrochloride (Cr-HCl) or creatine monohydrate (CrM) supplementation on anabolic/catabolic hormones, strength, and body composition. Forty participants with an age range of 18-25 years were randomly divided into four groups (n=10): RT+Cr-HCl (0.03 g.kg-1 of body mass), RT+CrM-loading phase (CrM-LP) (0.3 g.kg-1 of body mass for five days (loading) and 0.03 g.kg-1 body mass for 51 days (maintenance)), RT+CrM-without loading phase (CrM-WLP) (0.03 g.kg-1 body mass), and RT+placebo (PL). The participants consumed supplements and performed RT with an intensity of 70-85 % 1RM for eight weeks. Before and after the training and supplementation period, strength (1RM), body composition (percent body fat (PBF), skeletal muscle mass (SMM), muscular cross-sectional area (MCSA)) and serum levels of testosterone, growth hormone (GH), insulin-like growth factor-1 (IGF-1), cortisol, adrenocorticotropic hormone (ACTH), follistatin and myostatin were measured. The results showed that in the supplementation groups, strength, arm and thigh MCSA, and SMM significantly increased, and PBF significantly decreased (P≤0.05); this change was significant compared to the PL group (P≤0.05). In addition, the results showed a significant increase in GH, IGF-1 levels, the ratio of follistatin/myostatin, testosterone/cortisol (P≤0.05), and a significant decrease in cortisol and ACTH levels (P≤0.05) in the supplementation groups. Hormonal changes in GH, IGF-1, testosterone/cortisol, cortisol, and ACTH levels in the supplementation groups were significant compared to the PL group (P≤0.05). The results showed that CrM and Cr-HCl significantly enhanced the beneficial effects of RT on strength, hypertrophy, and hormonal responses, with Cr-HCl showing no benefit over CrM.
... En general, estos suplementos han sido investigados sin mezclarse con otros [78][79][80][81][82][83][84][85][86][118][119][120][121][122][123], a pesar de que habitualmente se utilizan de forma conjunta [60]. Dado que estos suplementos tienen diferentes vías fisiológicas para mejorar el rendimiento y la recuperación [92][93][94]110,129,[143][144][145], se podría asumir que la combinación de CrM y HMB pudiese tener mayor efecto que tomándolos por separado. Por ejemplo, algunos autores han demostrado efectos sinérgicos de 2 suplementos deportivos, como es el caso de la betaalanina y CrM, aumentando la capacidad física de trabajo en el umbral de fatiga neuromuscular [82,146]. ...
... Mientras que la T es una hormona anabólica y anticatabólica que indica el grado de regeneración endógena, el C indica estrés acumulado [41]. En este sentido, la ingesta de HMB puede reducir los niveles de C en sangre [185] y el CrM puede aumentar los niveles de T [92,144] cuando se toman individualmente. Solo hubo un estudio que analizó el estado hormonal cuando se ingirió la mezcla de suplementos [148], y no se mostraron diferencias en los niveles de C o T después de 6 semanas de suplementación. ...
... Las diferencias en los niveles de T podrían deberse a la duración de la intervención (6 semanas en el estudio de Crowe y O'Connor [148] a diferencia de las 10 semanas en el presente estudio), dado que la T requiere una intervención a largo plazo para producir cambios significativos [40,41]. Además, los resultados presentados sobre T y T/C podrían significar una mejor adaptación/recuperación del entrenamiento mediada por la combinación de CrM y HMB [126,144]. Estos resultados fueron corroborados por un efecto sinérgico de la suplementación combinada (CrM más HMB) sobre T y T/C y un efecto antagonista sobre el C. Sin embargo, después de revisar la literatura, hasta donde sabemos, los mecanismos por los cuales la combinación de CrM más HMB, aumentan la T y la relación T/C no están claros; por lo tanto, se necesita más investigación. ...
El monohidrato de creatina (CrM) y el β-hidroxi β-metilbutirato (HMB) son suplementos deportivos ampliamente estudiados. Sin embargo, no está claro cómo actúan cuando se utilizan conjuntamente en el ámbito deportivo. Hay que añadir que la incógnita es todavía mayor, cuando hablamos de un deporte de carácter predominantemente aeróbico como el remo.
Los objetivos de esta tesis han sido: 1) determinar mediante una revisión sistemática la eficacia de mezclar CrM más HMB en comparación con sus efectos aislados sobre el rendimiento deportivo, la composición corporal, los marcadores de daño muscular inducidos por el ejercicio (EIMD) y las hormonas anabólico-catabólicas. 2) determinar la eficacia y el grado de potenciación de 10 semanas de suplementación con CrM más HMB en el rendimiento deportivo, que se midió mediante una prueba incremental en remeros tradicionales de élite masculinos. 3) determinar el efecto y el grado de potenciación de 10 semanas de suplementación con CrM más HMB en los EIMD y hormonas anabólicas/catabólicas.
En base a los objetivos planteados, los principales resultados de la tesis indican que: 1) La combinación de CrM más 3 g/día de HMB durante 1–6 semanas podría producir efectos positivos en el rendimiento deportivo (fuerza y rendimiento anaeróbico) y durante 4 semanas en la composición corporal (aumento de grasa masa libre y disminución de la masa grasa). 2) La ingesta de CrM más HMB durante 10 semanas mostró un efecto sinérgico sobre la potencia aeróbica durante una prueba incremental. 3) La combinación de CrM más HMB presentó un efecto sinérgico sobre la testosterona y la ratio testosterona/cortisol y un efecto antagonista sobre el cortisol en comparación con la suma de la suplementación individual o aislada.
Las conclusiones obtenidas en la presente tesis doctoral indican que la combinación de estos dos suplementos puede ser de gran ayuda para los profesionales que rodean al deportista para mejorar el rendimiento aeróbico y la recuperación.
... During the measurements, the volunteers remained seated on a comfortable couch in an environment without noise. The rate-pressure product (RPP) was calculated as SBP × heart rate (mm Hg × bpm), as it is considered a reliable predictor of myocardial oxygen demand [19]. ...
... The central mechanism involves the transmission of impulses from the motor cortex to the cardiovascular control center. On the other hand, the peripheral mechanism consists of a reflex pathway with multiple control bases [19,21]. Finally, the increase in blood pressure could also be influenced by the number of motor units requested. ...
... The results of this study suggest that with increased exercise workload, the myocardial oxygen increases. The mechanism(s) of this increase may be coupled increases in HR and SBP [19]. ...
With regard to blood pressure responses to plyometric exercise and decreasing blood pressure after exercise (post-exercise hypotension), the influence of different workloads of plyometric exercise on blood pressure is not clear.
The purpose of this investigation was to examine the effects of a low, moderate and high workload of plyometric exercise on the post-exercise systolic (SBP) and diastolic blood pressure (DBP), heart rate (HR) and rate-pressure product (RPP) responses in athletes.
TEN MALE ATHLETES (AGE: 22.6 ±0.5 years; height: 178.2 ±3.3 cm; and body mass: 75.2 ±2.8 kg) underwent PE protocols involving 5 × 10 reps (Low Workload - LW), 10 × 10 reps (Moderate Workload - MW), and 15 × 10 reps (High Workload - HW) depth jump exercise from a 50-cm box in 3 non-consecutive days. After each exercise session, SBP, DBP and HR were measured every 10 min for a period of 70 min.
No significant differences were observed among post-exercise SBP and DBP when the protocols (LW, MW and HW) were compared. The MW and HW protocols showed greater increases in HR compared with LW. Also the HW indicated greater increases than LW in RPP at post-exercise (p < 0.05).
All protocols increased SBP, HR and RPP responses at the 10(th) and 20(th) min of post-exercise. With regard to different workloads of plyometric exercise, HW condition indicated greater increases in HR and RPP and strength and conditioning professionals and athletes must keep in their mind that HW of plyometric exercise induces greater cardiovascular responses.
... Perhaps alterations in sympathetic nervous system function and vasculature responsiveness and the baroreflex are involved in the increases in blood pressure following plyometric exercise [21]. Other possible mechanisms for increases in blood pressure may be increases in HR and sympathetic nerve activity [22]. The effects of plyometric exercise on HR are not well understood. ...
... In the present study, we found increases in HR, and depth jumps induced greater increases (Fig. 2 ). The forces and intensity of plyometric exercise , greater involvement of the fast twitch muscle fibres and the size of the activated muscle mass may also stimulate increases in HR [22, 23]. The exact mechanism by which the enhancement in HR following plyometric exercise occurs is unclear; however, motor unit recruitment may be increased during plyometric exercise [24]. ...
... RPP is regarded as an important noninvasive means of estimating myocardial oxygen demand [23] . A significant increase in RPP is produced during plyometric exercise in response to increases in HR together with SBP [22]. Significant increases in the blood lactate concentration were found following plyometric exercise in female volleyball and handball players. ...
Although plyometrics are widely used in athletic conditioning, the acute cardiovascular responses to plyometric exercise in female subjects have not been described. The purpose of this study was to assess the acute effects of plyometric exercise on cardiovascular responses, as well as blood lactate concentrations in female volleyball and handball players. Eight semiprofessional volleyball plays and ten handball players volunteered to participate in this study. Subjects performed five sets of box jumps and depth jumps with ten repetitions, respectively. After each set of exercises, blood pressure and heart rate were assessed. Blood lactate concentration was measured before and after exercise. Muscle soreness was also measured immediately before and immediately after plyometric exercise as well as 24, 48 and 72 h after plyometric exercise. No differences were found in any physiological indices between volleyball and handball players, except heart rate during box jump set 2 and the rate pressure product (RPP) during box jump sets 2 and 5 and depth jump set 1 (P > 0.05). Plyometric exercise increased heart rate, systolic and diastolic blood pressure, and RPP after each set of exercises (P < 0.05). Also, heart rate and RPP were higher during the depth jump exercise (P < 0.05). Plyometric exercise did not induce any significant changes in muscle soreness (P > 0.05). The blood lactate concentrations were significantly increased above resting levels (P < 0.05). These findings suggest that plyometric box and depth jumping can be used in an overall programme to properly prepare athletes for competition in events that require both aerobic and anaerobic metabolism components.
... When given a loading dose of creatine (0.3g x kg/day) for seven days, short-term creatine supplementation was shown to have no significant effect on resting heart rate or blood pressure in healthy men [9]. Similarly, seven days of supplementation (20g/day) showed no significant differences between creatine and placebo group in systolic blood pressure, diastolic blood pressure, mean arterial pressure, heart rate, and rate pressure product during exercise and rest [10]. Interestingly, a three-week creatine intervention (10g/day) was found to attenuate increases in brachial-ankle PWV (B-A PWV) in response to exercise [11]. ...
... No significant absolute reductions were reported in blood pressure or arterial stiffness related variables. Similarly, Arazi et al. [10] were unable to detect changes in SBP, diastolic BP (DBP), and mean arterial blood pressure (MAP), at rest after one week of creatine loading. Utilizing a shorter dosing period (5 days), Mihic et al. (14) found no significant changes in measurements of peripheral BP. ...
... In order to reduce EIMD and modify testosterone and T/C, as indicators of better recovery status [1,17,18], different ergogenic aids, such as creatine monohydrate (CrM) and β-hydroxy β-methylbutyrate (HMB), have been proposed [19,20]. In this sense, CrM has been shown to potentially reduce CK [21][22][23], LDH [21,23], and cortisol [24] levels and increase testosterone levels [24,25]. The pathway by which CrM may prevent or delay fatigue, reduce EIMD, and improve anabolic/catabolic hormones is that CrM supplementation increases muscle phosphocreatine (PCr) storage [26], and therefore, fatigue-produced muscle degeneration can be prevented or delayed by the CK/PCr system. ...
... In order to reduce EIMD and modify testosterone and T/C, as indicators of better recovery status [1,17,18], different ergogenic aids, such as creatine monohydrate (CrM) and β-hydroxy β-methylbutyrate (HMB), have been proposed [19,20]. In this sense, CrM has been shown to potentially reduce CK [21][22][23], LDH [21,23], and cortisol [24] levels and increase testosterone levels [24,25]. The pathway by which CrM may prevent or delay fatigue, reduce EIMD, and improve anabolic/catabolic hormones is that CrM supplementation increases muscle phosphocreatine (PCr) storage [26], and therefore, fatigue-produced muscle degeneration can be prevented or delayed by the CK/PCr system. ...
Creatine monohydrate (CrM) and β-hydroxy β-methylbutyrate (HMB) are widely studied ergogenic aids. However, both supplements are usually studied in an isolated manner. The few studies that have investigated the effect of combining both supplements on exercise-induced muscle damage (EIMD) and hormone status have reported controversial results. Therefore, the main purpose of this study was to determine the effect and degree of potentiation of 10 weeks of CrM plus HMB supplementation on EIMD and anabolic/catabolic hormones. This study was a double-blind, placebo-controlled trial where participants (n = 28) were randomized into four different groups: placebo group (PLG; n = 7), CrM group (CrMG; 0.04 g/kg/day of CrM; n = 7), HMB group (HMBG; 3 g/day of HMB; n = 7), and CrM-HMB group (CrM-HMBG; 0.04 g/kg/day of CrM plus 3 g/day of HMB; n = 7). Before (baseline, T1) and after 10 weeks of supplementation (T2), blood samples were collected from all rowers. There were no significant differences in the EIMD markers (aspartate aminotransferase, lactate dehydrogenase, and creatine kinase) among groups. However, we observed significant differences in CrM-HMBG with respect to PLG, CrMG, and HMBG on testosterone (p = 0.006; η²p = 0.454) and the testosterone/cortisol ratio (T/C; p = 0.032; η²p = 0.349). Moreover, we found a synergistic effect of combined supplementation on testosterone (CrM-HMBG = −63.85% vs. CrMG + HMBG = −37.89%) and T/C (CrM-HMBG = 680% vs. CrMG + HMBG = 57.68%) and an antagonistic effect on cortisol (CrM-HMBG = 131.55% vs. CrMG + HMBG = 389.99%). In summary, the combination of CrM plus HMB showed an increase in testosterone and T/C compared with the other groups after 10 weeks of supplementation. Moreover, this combination presented a synergistic effect on testosterone and T/C and an antagonistic effect on cortisol compared with the sum of individual or isolated supplementation.
... Given that these two supplements have different physiological pathways to improve performance [13][14][15]28,29,[32][33][34], it could be assumed that the combination of both complements would improve sports performance compared to taking them alone. Therefore, some authors have considered the utilization of both supplements together (CrM plus HMB) with the aim of producing an additive or synergistic effect. ...
... HMB ingestion can reduce blood cortisol levels [64] and CrM can increase testosterone levels [32,33] when they are taken individually. There was only one study that analyzed hormone status when the mixed supplements were ingested [38], and it showed no differences in cortisol or testosterone levels after six weeks of supplementation. ...
Although there are many studies showing the isolated effect of creatine monohydrate (CrM) and β-hydroxy β-methylbutyrate (HMB), it is not clear what effect they have when they are combined. The main purpose of this systematic review was to determine the efficacy of mixing CrM plus HMB in comparison with their isolated effects on sports performance, body composition, exercise induced markers of muscle damage, and anabolic-catabolic hormones. This systematic review was carried out in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement guidelines and the PICOS model, for the definition of the inclusion criteria. Studies were found by searching PubMed/MEDLINE, Web of Science (WOS), and Scopus electronic databases from inception to July 3rd 2019. Methodological quality and risk of bias were assessed by two authors independently, and disagreements were resolved by third-party evaluation, in accordance with the Cochrane Collaboration Guidelines samples. The literature was examined regarding the effects of the combination of CrM plus HMB on sport performance using several outcome variables (athletic performance, body composition, markers of muscle damage, and hormone status). This systematic review included six articles that investigated the effects of CrM plus HMB on sport performance (two on strength performance, showing improvements in one of them; three on anaerobic performance, presenting enhancements in two of them; and one on aerobic performance, not presenting improvements), body composition (three on body mass, showing improvements in one of them; two on fat free mass, presenting increases in one of them; and two on fat mass, showing decreases in one of them) and markers of muscle damage and hormone status (four on markers of muscle damage and one on anabolic-catabolic hormones, not showing benefits in any of them). In summary, the combination of 3-10 g/day of CrM plus 3 g/day of HMB for 1-6 weeks could produce potential positive effects on sport performance (strength and anaerobic performance) and for 4 weeks on body composition (increasing fat free mass and decreasing fat mass). However, this combination seems to not show positive effects relating to markers of exercise-induced muscle damage and anabolic-catabolic hormones.
... Previous research has reported seasonal variations in testosterone levels [17], however, based on the current research design we are unclear why there was a main effect of time and future research may be warranted. To date, there is some, albeit limited, evidence demonstrating a small increase in testosterone follow creatine supplementation [18], however, the majority of studies found no increase in testosterone [13,14,[19][20][21][22][23]. Overall, based on our current study and the majority of the evidence, creatine does not influence testosterone (free or total) and DHT. ...
Background
Creatine is a widely used ergogenic aid that enhances muscle strength and lean mass. However, concerns have been raised about the potential role in promoting hair loss by increasing dihydrotestosterone (DHT). Currently, there is no direct evidence examining the relationship between creatine supplementation and hair follicle health. Therefore, the purpose was to determine the effects of 12 weeks of creatine supplementation on androgen levels and hair follicle health in healthy young males.
Methods
Forty-five resistance-trained males (ages 18–40 years) were recruited and randomly assigned to either a creatine monohydrate (5 g/day) or placebo (5 g maltodextrin/day) group. Participants maintained their habitual diets and training routines. Blood samples were collected at baseline and after 12 weeks to measure total testosterone, free testosterone, and DHT. Hair follicle health was assessed using the Trichogram test and the FotoFinder system (hair density, follicular unit count, and cumulative hair thickness). Statistical analyses were performed using repeated measures ANOVA, and potential outliers were examined through sensitivity analysis.
Results
Thirty-eight participants completed the study, with no significant differences in baseline characteristics between groups. There were no group-by-time interactions observed for any hormones or hair-related outcomes (p > 0.05). While total testosterone increased (∆ = post value minus pre value: creatine = ∆124 ± 149 ng/dL; placebo = ∆216 ± 203 ng/dL) and free testosterone decreased (creatine = ∆-9.0 ± 8.7 pg/mL; placebo = ∆-9 ± 6.4 pg/mL) over time, these effects were independent of supplementation. There were no significant differences in DHT levels, DHT-to-testosterone ratio, or hair growth parameters between the creatine and placebo groups.
Conclusion
This study was the first to directly assess hair follicle health following creatine supplementation, providing strong evidence against the claim that creatine contributes to hair loss.
... Although plyometrics are widely used in athletic conditioning by coaches, the university athlete's blood pressure responses to plyometric training have not been well established. Arazi et al. (2015) investigated the resting hormonal and cardiovascular responses to short term creatine supplementation and resistance exercises. The report showed that high workload indicated greater increases in HR and RPP. ...
The study examined the effectiveness of plyometric training on university athletes’ blood pressure. Six plyometric training exercises were used for the study. Ankle hops, squat jumps and tuck jumps were chosen for lower body plyomeric training while push-ups, medicine ball-chest throws and side throws were used for upper body plyometric training with moderate intensity. The quasi-experimental research design was adopted for the study. 30 male athletes who voluntarily participated in the study were purposively selected and drawn from university male athletes body mass index (BMI) within the range of underweight to normal weight (≤18.5±24.9) (height, x=1.50±1.17cm; body weight, x=50.31±70.15kg), all athletes whose age-range fall between 18 and 25 years old. The general data were collated and analysed. Mean and standard deviation were used to describe the data collected for the study, Analysis of co-variance (ANCOVA) were used to test the hypotheses. The results revealed that athletes who were trained using LBPT and UBPT had reduced HR, SBP, and DBP better than those in the control group. These positive effects on blood pressure no doubt help in reducing the risk of cardiovascular diseases and promote good healthy lifestyle. Based on the findings, recommendations and conclusions were made.
... As with any supplement, individual responses can be influenced by various factors, including genetics, overall health, and lifestyle. 55 For athletes who wish to gain weight or overall mass, creatine may be an option. Because the evidence in this study shows that water retention is a source of weight gain and not strictly FFM, it is incorrect to assume that creatine supplementation alone will increase athletic performance. ...
Background Creatine is a nutritional supplement commonly used to increase strength performance and muscle mass, but its effects on female wrestlers are still unclear and equivocal. The purpose of the present study is to investigate the efficacy of short-term creatine monohydrate supplementation combined with strength training on the physical fitness characteristics and muscle hypertrophy in junior women wrestlers.
Methodology Eighteen women wrestlers (age = 18.7 ± 0.9 years, body mass index = 21.4 ± 2.5 kg/m2) participated in this research. Participants were randomly divided into three groups: Experimental Group 1—EXP1: (training with creatine supplementation), Experimental Group 2—EXP2: (training without creatine supplementation), and Control group (without training or creatine supplementation). Strength training was performed for 6 weeks, four sessions per week, with a training intensity ranging from 65 to 75% of the maximal heart rate reserve and one-repetition maximum. EXP1 was supplemented with 10 g creatine during training days. Various physical fitness characteristics and muscle hypertrophy variables were collected at three time points (pretest, midtest, and posttest).
Results A number of variables were significantly improved in the EXP1 after 6 weeks (weight, body mass index, one-repetition maximum, agility, muscular power, and hypertrophy) but not in the EXP2 and control groups.
Conclusion Short-term creatine supplementation, in conjunction with strength training, emerges as a highly effective approach for enhancing hypertrophy and boosting physical fitness factors in female wrestlers. Therefore, it is recommended that junior wrestlers individuals supplement with creatine during their strength training routines.
... Previous studies have demonstrated a positive correlation between testosterone and lean body mass and muscular strength [42][43][44]. Our results support previous research that reported a significant elevation in resting testosterone concentration [45,46] after Cr loading and no alteration following BA supplementation [21]. In contrast, some studies have shown that Cr loading did not change hormonal status [47,48]. ...
The purpose was to investigate the effects of a 7-day creatine (Cr) loading protocol at
the end of four weeks of β-alanine supplementation (BA) on physical performance, blood lactate,
cognitive performance, and resting hormonal concentrations compared to BA alone. Twenty male
military personnel (age: 21.5 ± 1.5 yrs; height: 1.78 ± 0.05 m; body mass: 78.5 ± 7.0 kg; BMI:
23.7 ± 1.64 kg/m2
) were recruited and randomized into two groups: BA + Cr or BA + placebo (PL).
Participants in each group (n = 10 per group) were supplemented with 6.4 g/day of BA for 28 days.
After the third week, the BA + Cr group participants were also supplemented with Cr (0.3 g/kg/day),
while the BA + PL group ingested an isocaloric placebo for 7 days. Before and after supplementation,
each participant performed a battery of physical and cognitive tests and provided a venous blood
sample to determine resting testosterone, cortisol, and IGF-1. Furthermore, immediately after the
last physical test, blood lactate was assessed. There was a significant improvement in physical
performance and mathematical processing in the BA + Cr group over time (p < 0.05), while there
was no change in the BA + PL group. Vertical jump performance and testosterone were significantly
higher in the BA + Cr group compared to BA + PL. These results indicate that Cr loading during the
final week of BA supplementation (28 days) enhanced muscular power and appears to be superior
for muscular strength and cognitive performance compared to BA supplementation alone.
... doses ranging from 3-25 g/ day for 6 days to 12 weeks) on testosterone. Two studies reported small, physiologically insignificant increases in total testosterone after six and seven days of supplementation [65,66], while the remaining ten studies reported no change in testosterone concentrations. In five of these studies [67][68][69][70][71], free testosterone, which the body uses to produce DHT, was also measured and no increases were found. ...
Supplementing with creatine is very popular amongst athletes and exercising individuals for improving muscle mass, performance and recovery. Accumulating evidence also suggests that creatine supplementation produces a variety of beneficial effects in older and patient populations. Furthermore, evidence-based research shows that creatine supplementation is relatively well tolerated, especially at recommended dosages (i.e. 3-5 g/day or 0.1 g/kg of body mass/day). Although there are over 500 peer-refereed publications involving creatine supplementation, it is somewhat surprising that questions regarding the efficacy and safety of creatine still remain. These include, but are not limited to: 1. Does creatine lead to water retention? 2. Is creatine an anabolic steroid? 3. Does creatine cause kidney damage/renal dysfunction? 4. Does creatine cause hair loss / baldness? 5. Does creatine lead to dehydration and muscle cramping? 6. Is creatine harmful for children and adolescents? 7. Does creatine increase fat mass? 8. Is a creatine ‘loading-phase’ required? 9. Is creatine beneficial for older adults? 10. Is creatine only useful for resistance / power type activities? 11. Is creatine only effective for males? 12. Are other forms of creatine similar or superior to monohydrate and is creatine stable in solutions/beverages? To answer these questions, an internationally renowned team of research experts was formed to perform an evidence-based scientific evaluation of the literature regarding creatine supplementation.
... There have been no systematic reviews on blood pressure changes or adverse cardiovascular effects of creatine supplementation in relatively healthy male or mix-sex populations. However, our finding is consistent with no reported blood pressure effect in three published male only placebo-controlled trials with creatine [160][161][162] and one mix-sex study [144]. There has been one systematic review on the use of creatine and creatine analogues in hypertension and cardiovascular disease, which also concluded no change in blood pressure with creatine supplementation in myocardial infarction or heart failure trials [163]. ...
Creatine Monohydrate (CrM) is a dietary supplement routinely used as an ergogenic aid for sport and training, and as a potential therapeutic aid to augment different disease processes. Despite its increased use in recent years, studies reporting potential adverse outcomes of CrM have been mostly derived from male or mixed sex populations. A systematic search was conducted, which included female participants on CrM, where adverse outcomes were reported, with meta-analysis performed where appropriate. Six hundred and fifty-six studies were identified where creatine supplementation was the primary intervention; fifty-eight were female only studies (9%). Twenty-nine studies monitored for adverse outcomes, with 951 participants. There were no deaths or serious adverse outcomes reported. There were no significant differences in total adverse events, (risk ratio (RR) 1.24 (95% CI 0.51, 2.98)), gastrointestinal events, (RR 1.09 (95% CI 0.53, 2.24)), or weight gain, (mean difference (MD) 1.24 kg pre-intervention, (95% CI −0.34, 2.82)) to 1.37 kg post-intervention (95% CI −0.50, 3.23)), in CrM supplemented females, when stratified by dosing regimen and subject to meta-analysis. No statistically significant difference was reported in measures of renal or hepatic function. In conclusion, mortality and serious adverse events are not associated with CrM supplementation in females. Nor does the use of creatine supplementation increase the risk of total adverse outcomes, weight gain or renal and hepatic complications in females. However, all future studies of creatine supplementation in females should consider surveillance and comprehensive reporting of adverse outcomes to better inform participants and health professionals involved in future trials.
... Equally, muscle glycogen levels can be positively affected by CrM through the inhibition and/or activation of certain glycogen synthase regulatory proteins, highlighting the IGF-I/Akt-PKB/GSK3 pathway, the possible inhibition of AMPK and cell swelling [13] which are essential in glycolytic sports. Moreover, CrM improves recovery stimulating muscle protein synthesis by the activation of signaling cascades and an increase in the expression of proteins involved in these processes and inactivation and/or reduction in the expression of proteins with ergolytic functions [14], increasing testosterone levels [15] and/or reducing the post-training lactate (LA) concentration [16], lactate dehydrogenase (LDH) [17] and creatine kinase (CK) [17], which are essential to achieve the desired training adaptation and hence, the opportunity to train more. ...
Creatine monohydrate (CrM) and β-hydroxy β-methylbutyrate (HMB) are common ergogenic aids in the field of sports and are frequently used in an isolated way. However, there are a few studies that have investigated the effect of combining both supplements on different variables related to performance, with controversial results. Therefore, the main purpose of this study was to determine the efficacy and the degree of potentiation of 10 weeks of CrM plus HMB supplementation on sports performance, which was measured by an incremental test to exhaustion in elite male traditional rowers. In this placebo-controlled, double-blind trial, 10-week study, participants (n = 28) were randomized to a placebo group (PLG; n = 7), CrM group (0.04 g/kg/day of CrM; n = 7), HMB group (3 g/day of HMB; n = 7) and CrM-HMB group (0.04 g/kg/day of CrM plus 3 g/day of HMB; n = 7). Before and after 10 weeks of different treatments, an incremental test was performed on a rowing ergometer to calculate the power that each rower obtained at the anaerobic threshold (WAT), and at 4 mmol (W4) and 8 mmol (W8) of blood lactate concentration. There were no significant differences in WAT and W4 among groups or in body composition. However, it was observed that the aerobic power achieved at W8 was significantly higher in the CrM-HMB group than in the PLG, CrM and HMB groups (p < 0.001; η2p = 0.766). Likewise, a synergistic effect of combined supplementation was found for the sum of the two supplements separately at WAT (CrM-HMBG = 403.19% vs. CrMG+HMBG = 337.52%), W4 (CrM-HMBG = 2736.17% vs. CrMG+HMBG = 1705.32%) and W8 (CrM-HMBG = 1293.4% vs. CrMG+HMBG = 877.56%). In summary, CrM plus HMB supplementation over 10 weeks showed a synergistic effect on aerobic power (measured as WAT, W4, and W8) during an incremental test but had no influence muscle mass.
... There is not much research on the effect of CEE supplementation on hormonal levels, and most studies have been conducted on creatine monohydrate supplementation. In this regard, the results of Arazi et al. [2] showed that creatine supplementation consumption more than 5 days a week combined with RT is sufficient to increase the concentration of testosterone levels and reduce the concentration of cortisol. Also, the results of Deldicque et al. [14] showed that creatine supplementation does not increase protein synthesis more than exercise alone. ...
Study aim: The aim of this study to determine whether creatine ethyl ester (CEE) supplementation combined with resistance training (RT) is effective for improving hormonal changes, body composition and muscle strength in underweight non-athlete men.
Materials and methods: Sixteen underweight non-athlete men participated in this double-blind study and were randomly assigned to one of two groups: RT with placebo (RT + PL, n = 8) and RT with CEE supplementation (RT + CEE, n = 8). The participants performed 6 weeks of RT (60–80% 1RM) combined with CEE or PL. 48 hours before and after the training period, muscle strength (1RM for leg press and bench press), body composition (percentage of body fat, circumference measurements of the arm and thigh), serum levels of testosterone, cortisol, and growth hormone (GH) of the participant were measurements.
Results: Significant increases were observed for weight, muscle strength and muscle mass, serum levels of testosterone and GH between pre and post-test in the RT + CEE group (p < 0.05). In addition, cortisol level was significantly decreased in the post-test in the RT+CEE group. The decrease in fat percent was greater in the RT + PL group than in the RT + CEE group (%change = –6.78 vs. –0.76, respectively). Weight and leg strength changes in the RT + CEE group were significant compared to the RT + PL group (p < 0.001, p = 0.05, p = 0.001; respectively). However, in other variables, despite the increase of GH and testosterone levels and lower levels of cortisol in the RT + CEE group, no significant differences were observed between the two groups (p < 0.05).
Conclusion: It seems that the consumption of CEE combined with RT can have significant effects on body weight and leg strength in underweight non-athlete men. This supplement may provide a potential nutritional intervention to promote body weight in underweight men.
... In general, most of the investigations on Cr supplementation have reported an increase in the intracellular volume without notorious changes in extracellular volume (67,73,74,75,76), probably because of the high osmotic charge associated to the increase in Cr and Na + in cytosol. In fact, cell swelling has been marked as an anabolic signal (77), which in turn can stimulate the activation of osmosensing molecules as G protein coupled receptors in the MAPK pathway and sphingosine kinase (SPHK1), creating a positive feedback motif. ...
In recent years the research problem in the field of sports supplementation has changed to explain the metabolic mechanisms by which creatine (Cr) administration enhances the performance of certain sports
or simply benefits the muscular adaptation. In this review for first time the biochemical mechanisms of Cr ingestion in a cell signaling insight were analyzed, focusing on energetic bioavailability enhancement and optimization of the temporal and spatial buffering of Cr/PCr/CK system. Moreover, intensification in proliferation and differentiation processes of muscle cells (IGF-I/PI3K/Akt-PKB, SPHK1/MAPK/p38/MRFs, mTOR, cellular swelling, mitotic activity of satellite cells, actin polymerization, and myoblast fusion) and inactivation and/or reduction in the expression of ergolitic metabolites (GSK3β, myostatin and AMPK regulation) were examined. In this way, we explained from a metabolic point of view the increase in
muscle mass, strength, fatigue resistance, and performance of high intensity sports after Cr monohydrate supplementation.
... Benefits of creatine supplementation have been identified in the healthy population who are undertaking resistance training. These include improvements in muscle size and strength (13,41,42); increases in serum testosterone concentrations and reduction in Dietary Supplementation During Musculoskeletal Injury VOLUME 0 | NUMBER 0 | MONTH 2015 cortisol concentrations (2); and improvements in physical performance (27,44,45) and body composition (43). ...
THIS ARTICLE IS A COMMENTARY TO OUTLINE THE POTENTIAL BENEFITS OF USING 2 SPECIFIC DIETARY SUPPLEMENTS DURING REHABILITATION FROM MUSCULOSKELETAL INJURY. JUSTIFICATION AND EXPLANATION ARE PROVIDED FOR THE USE OF PROTEIN AND CREATINE SUPPLEMENTS DURING AN EXERCISE PROGRAM TO INCREASE PROTEIN SYNTHESIS AND MUSCLE FUNCTION, AND TO IMPROVE ENERGY PRODUCTION TO PREVENT FATIGUE. EVIDENCE SUGGESTS POTENTIAL BENEFITS FOR THESE SUPPLEMENTS TO BE USED IN THIS POSTINJURY PERIOD, AT A TIME WHEN MANY INDIVIDUALS WILL ABSTAIN FROM SUPPLEMENTATION. SUGGESTIONS ARE MADE FOR PROFESSIONALS WORKING WITH INJURED OR RECOVERING INDIVIDUALS TO CONSIDER ADVISING THEM TO SUSTAIN THE SUPPLEMENTATION REGIMES.
A creatina (ácido α-metil guanidino acético) é um composto amplamente utilizado pelos praticantes de atividade física, em especial pelos que fazem treinos resistidos, como a musculação, com a premissa de melhorar o desempenho físico e recuperação muscular dos atletas. Seus efeitos para estes fins estão comprovados em muitos estudos na literatura, porém, seus efeitos cardiovasculares ainda não estão bem estabelecidos. Desta forma, o objetivo deste estudo é investigar sobre quais os efeitos cardíacos do uso contínuo de creatina. Para isso, foi realizada uma revisão de literatura com estudos publicados nos últimos 10 anos nas bases de dados da PubMed, Science Direct e Web of Science. Inicialmente, foram encontrados 443 estudos, os quais foram criteriosamente selecionados através dos critérios de inclusão e exclusão pré-estabelecidos, restando 11 estudos para compor a amostra final de resultados da pesquisa. Destes, 12.355 pacientes foram analisados no total, os quais estabeleceram que a suplementação de creatina oferece diversos benefícios cardiovasculares, particularmente em termos de proteção e eficiência energética cardíaca, função endotelial e adaptação ao estresse físico, enquanto apresenta um perfil de segurança favorável sem impactos adversos significativos nas funções cardíacas básicas. Conclui-se, portanto, que os efeitos cardiovasculares da suplementação de creatina são complexos e, em muitos casos, benéficos. A creatina oferece proteção contra danos cardíacos, melhora a função endotelial e pode influenciar positivamente a adaptação cardiovascular ao exercício.
The purpose of this study was to assess the effects of listening to music during warm-up and resistance exercise on physiological (heart rate and blood pressure) and psychophysical (rating of perceived exertion) responses in trained athletes. Twelve strength trained male participants performed a warm up and resistance exercise without music (WU+RE without M), warm up and resistance exercise with music (WU+RE with M), WU with M and RE without M, and WU without M and RE with M, with 48 hours space between sessions. After competing each session, the rating of perceived exertion (RPE) was measured. Also, heart rate (HR), systolic (SBP) and diastolic blood pressure (DBP), mean arterial pressure (MAP), and rate pressure product (RPP) were assessed pre, post, 15, 30, 45, and 60 min post exercise. Results indicated that RPE was higher for WU+RE without M condition in comparison with other conditions. All conditions showed increases in cardiovascular variables post-exercise. The responses of HR, SBP and RPP were higher for WU+RE without M condition. Thus, using music during warm up and resistance exercise is a legal method for decreasing RPE and cardiovascular responses due to resistance exercise.
To quantify the duration of postexercise hypotension at different exercise intensities, we studied six unmedicated, mildly hypertensive men matched with six normotensive controls.
Each subject wore a 24-hour ambulatory blood pressure monitor at the same time of day for 13 consecutive hours on 3 different days. On each of the 3 days, subjects either cycled for 30 minutes at 40% or 70% maximum VO2 or performed activities of daily living. There was no intensity effect on the postexercise reduction in blood pressure, so blood pressure data were combined for the different exercise intensities. Postexercise diastolic blood pressure and mean arterial pressure were lower by 8 +/- 1 (p less than 0.001) and 7 +/- 1 mm Hg (p less than 0.05), respectively, than the preexercise values for 12.7 hours in the hypertensive group. These variables were not different before and after exercise in the normotensive group. Systolic blood pressure was reduced by 5 +/- 1 mm Hg (p less than 0.05) for 8.7 hours after exercise in the hypertensive group. In contrast, systolic blood pressure was 5 +/- 1 mm Hg (p less than 0.001) higher for 12.7 hours after exercise in the normotensive group. When the blood pressure response on the exercise days was compared with that on the nonexercise day, systolic blood pressure (135 +/- 1 versus 145 +/- 1 mm Hg) and mean arterial pressure (100 +/- 1 versus 106 +/- 1 mm Hg) were lower (p less than 0.05) on the exercise days in the hypertensive but not in the normotensive group. We found a postexercise reduction in mean arterial pressure for 12.7 hours independent of the exercise intensity in the hypertensive group. Furthermore, mean arterial pressure was lower on exercise than on nonexercise days in the hypertensive but not in the normotensive group.
These findings indicate that dynamic exercise may be an important adjunct in the treatment of mild hypertension.
Creatine (Cr) supplementation has become a common practice among professional, elite, collegiate, amateur, and recreational athletes with the expectation of enhancing exercise performance. Research indicates that Cr supplementation can increase muscle phosphocreatine (PCr) content, but not in all individuals. A high dose of 20 g x d(-1) that is common to many research studies is not necessary, as 3 g x d(-1) will achieve the same increase in PCr given time. Coincident ingestion of carbohydrate with Cr may increase muscle uptake; however, the procedure requires a large amount of carbohydrate. Exercise performance involving short periods of extremely powerful activity can be enhanced, especially during repeated bouts of activity. This is in keeping with the theoretical importance of an elevated PCr content in skeletal muscle. Cr supplementation does not increase maximal isometric strength, the rate of maximal force production, nor aerobic exercise performance. Most of the evidence has been obtained from healthy young adult male subjects with mixed athletic ability and training status. Less research information is available related to the alterations due to age and gender. Cr supplementation leads to weight gain within the first few days, likely due to water retention related to Cr uptake in the muscle. Cr supplementation is associated with an enhanced accrual of strength in strength-training programs, a response not independent from the initial weight gain, but may be related to a greater volume and intensity of training that can be achieved. There is no definitive evidence that Cr supplementation causes gastrointestinal, renal, and/or muscle cramping complications. The potential acute effects of high-dose Cr supplementation on body fluid balance has not been fully investigated, and ingestion of Cr before or during exercise is not recommended. There is evidence that medical use of Cr supplementation is warranted in certain patients (e.g.. neuromuscular disease); future research may establish its potential usefulness in other medical applications. Although Cr supplementation exhibits small but significant physiological and performance changes, the increases in performance are realized during very specific exercise conditions. This suggests that the apparent high expectations for performance enhancement, evident by the extensive use of Cr supplementation, are inordinate.
Resistance exercise has been shown to elicit a significant acute hormonal response. It appears that this acute response is more critical to tissue growth and remodelling than chronic changes in resting hormonal concentrations, as many studies have not shown a significant change during resistance training despite increases in muscle strength and hypertrophy. Anabolic hormones such as testosterone and the superfamily of growth hormones (GH) have been shown to be elevated during 15-30 minutes of post-resistance exercise providing an adequate stimulus is present. Protocols high in volume, moderate to high in intensity, using short rest intervals and stressing a large muscle mass, tend to produce the greatest acute hormonal elevations (e.g. testosterone, GH and the catabolic hormone cortisol) compared with low-volume, high-intensity protocols using long rest intervals. Other anabolic hormones such as insulin and insulin-like growth factor-1 (IGF-1) are critical to skeletal muscle growth. Insulin is regulated by blood glucose and amino acid levels. However, circulating IGF-1 elevations have been reported following resistance exercise presumably in response to GH-stimulated hepatic secretion. Recent evidence indicates that muscle isoforms of IGF-1 may play a substantial role in tissue remodelling via up-regulation by mechanical signalling (i.e. increased gene expression resulting from stretch and tension to the muscle cytoskeleton leading to greater protein synthesis rates). Acute elevations in catecholamines are critical to optimal force production and energy liberation during resistance exercise. More recent research has shown the importance of acute hormonal elevations and mechanical stimuli for subsequent up- and down-regulation of cytoplasmic steroid receptors needed to mediate the hormonal effects. Other factors such as nutrition, overtraining, detraining and circadian patterns of hormone secretion are critical to examining the hormonal responses and adaptations to resistance training.
The purpose of this review was to summarize the acute cardiovascular responses of healthy young and older adults to resistance exercise and to review studies that have compared healthy younger and older populations. Intensity, duration, and active muscle mass are known to play important roles in the degree of pressor response elicited during resistance exercise in both young and older participants. Systolic, diastolic, and mean arterial pressure as well as heart rate rise in response to resistance exercise. Stroke volume generally remains unchanged but may significantly decrease with greater exercise intensity and active muscle mass. Cardiovascular variables such as cardiac output, rate-pressure product, and oxygen consumption increase comparably in the 2 groups. Also, total peripheral resistance may increase or decrease based on involved muscle mass and resistance type. Findings from this review suggest that acute cardiovascular responses to resistance exercise are similar in healthy young and older adults. This supports the inclusion of resistance exercise as part of an overall fitness program designed for healthy older adults.
(C) 1999 National Strength and Conditioning Association
This study investigated the influence of oral creatine monohydrate supplementation on hormone responses to high-intensity resistance exercise in 13 healthy, normally active men. Subjects were randomly assigned in double-blind fashion to either a creatine or placebo group. Both groups performed bench press and jump squat exercise protocols before (T1) and after (T1) ingesting either 25 g creatine monohydrate or placebo per day for 7 days. Blood samples were obtained pre- and 5 min postexercise to determine serum lactate, testosterone, and cortisol concentrations. Creatine ingestion resulted in a significant (p < 0.05) increase in body mass but no changes in skinfold thickness. Serum lactate concentrations were significantly higher at 5 min postexercise in both groups compared to resting values. From T1 to T2 there were no significant differences in postexercise lactate concentration during both exercise protocols in the placebo group, but the creatine group had significantly higher lactate concentrations after the bench press and a trend toward lower concentrations during the jump squat at T2. There were significant increases in testosterone concentration postexercise after the jump squat, but not the bench press, for both groups; 5-min postexercise cortisol concentrations did not differ significantly from preexercise values for both groups for either protocol. Creatine supplementation may increase body mass; however, test-osterone and cortisol may not mediate this initial effect.
(C) 1997 National Strength and Conditioning Association
Roundtable on the physiological and health effects of oral creatine supplementation
American College of Sports Medicine. Roundtable on the physiological and health effects of oral creatine supplementation.
Med Sci Sports Exerc 2000;32:706-17.