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Omega-3 fatty acids supplementation improves endothelial function and maximal oxygen uptake in endurance-trained athletes
Abstract
Abstract The study aimed to evaluate the effects of a 3-week n-3 polyunsaturated fatty acids (n-3 PUFA) supplementation on serum nitric oxide (NO), asymmetric dimethyloarginine (ADMA), ultrasound indices of endothelial function and maximal oxygen uptake ([Formula: see text]) of elite cyclists. The effects of dietary supplementation (n-3 PUFA at a dose of 1.3 g twice daily for 3 weeks) and placebo administration on flow-mediated dilatation (FMD), pulse wave velocity, serum markers (NO, ADMA), lipid profile, and [Formula: see text] were analysed in 13 cyclists both before and after dietary protocols. Significant differences between pre- and post-intervention baseline NO levels were observed after n-3 PUFA dietary protocol (13.9 ± 4.2 vs. 23.5 ± 3.6 µmol·l(-1); P < 0.001). Higher post-intervention baseline NO level was observed after n-3 PUFA diet compared with placebo (23.5 ± 3.6 vs. 15.3 ± 3.0 µmol·l (-1); P < 0.01, respectively). The n-3 PUFA increased baseline NO concentration (ΔNO) by 6.7 ± 3.8 µmol·l(-1) and placebo by 1.6 ± 4.4 µmol·l(-1). The positive correlation was observed between baseline post-intervention NO concentration and maximal oxygen uptake (r = 0.72; P < 0.01) and also between ΔNO and [Formula: see text] (r = 0.54; P < 0.05) in response to omega-3 fatty acids supplementation. There was an association between a 5.25% higher FMD (P < 0.05) and higher [Formula: see text] (P < 0.001) after n-3 PUFA diet compared with lower values of placebo (r = 0.68; P < 0.05). These findings suggest that an increase in NO release in response to n-3 PUFA supplementation may play a central role in cardiovascular adaptive mechanisms and enhanced exercise performance in cyclists.
... 399 mg of DHA increased exercise economy during a steady-state submaximal cycloergometer test. In one crossover study with trained cyclists, researchers observed an increase inVO 2max after 3 wk of supplementation with a daily dose of 660 mg of EPA and 440 mg of DHA (25). ...
... Given the large cross-sectional study indicating that inverse relationship betweeṅ VO 2max and C-reactive protein is modified by omega-3 fatty acid levels (29), this may be the case. Moreover, an increase in insulin sensitivity due to unsaturation of skeletal muscle membranes (30), improved calcium handling by skeletal muscle sarcoplasmic reticulum (23), and improved endothelial function via increase in NO release (25) should be taken into account in searching for potential mechanisms of action. Of note, in the present study, 13 out of 14 participants in the OMEGA group showed an improveḋ VO 2peak compared with a variable response in the MCT group, in which only 9 out of 12 runners improved their results. ...
... Compared with previous studies in which performance indicators were assessed, our supplementation protocol (2234 mg of EPA and 916 mg of DHA daily for 12 wk) was a higher dose over a longer supplementation period (9,(23)(24)(25). However, what values of O3I are sufficient for amateur and competitive athletes to optimize athletic performance remains a question to be answered in future studies. ...
Purpose
To investigate the effects of 12 weeks of omega-3 fatty acid supplementation during endurance training on Omega-3 index (O3I) and indicators of running performance in amateur long-distance runners.
Methods
26 amateur male long-distance runners aged ≥29 years supplemented omega-3 fatty acid capsules (OMEGA group, n = 14; 2234 mg of EPA and 916 mg of DHA daily) or medium chain triglycerides capsules as placebo (MCT group, n = 12; 4000 mg of MCT daily) during 12-week of endurance training. Before and after intervention, blood samples were collected for O3I assessment and an incremental test to exhaustion and 1500-m run trial were performed.
Results
O3I was significantly increased in the OMEGA group (from 5.8% to 11.6%, P < 0.0001). A significant increase in VO2peak was observed in the OMEGA group (from 53.6 ± 4.4 ml*kg-1*min-1 to 56.0 ± 3.7 ml*kg-1*min-1, P = 0.0219) without such change in MCT group (from 54.7 ± 6.8 ml*kg-1*min-1 to 56.4 ± 5.9 ml*kg-1*min-1, P = 0.1308). A positive correlation between the change in O3I and change in running economy was observed when data of participants from both groups were combined (-0.1808 ± 1.917, P = 0.0020), without such an effect in OMEGA group alone (P = 0.1741). No effect of omega-3 supplementation on 1500-m run results was observed.
Conclusions
12 weeks of omega-3 fatty acid supplementation at a dose of 2234 mg of EPA and 916 mg of DHA daily during endurance training resulted in improvement of O3I and running economy and increased VO2peak without improvement in the 1500-m run trial time in amateur runners.
... Although some studies show no improvements in cardiopulmonary-muscle oxidative function following supplementation with fish oil containing omega-3 fatty acids [5,6], several studies do indicate a positive effect. For example, long-term EPA and DHA supplementation may contribute to the improvement in VO 2max [7] or to the reduction in the cost of aerobic exercise in trained cyclists [8,9]. Moreover, our recent study showed that 12-week supplementation with omega-3 fatty acids improved running economy (RE) in amateur runners [10]. ...
... These effects are related to the incorporation of EPA and DHA into the erythrocyte cell membrane [31], skeletal muscles [32] and heart [33]. Furthermore, the systemic response to supplementation with omega-3 fatty acids as exemplified by maximum oxygen uptake [7], exercise economy [9,10] or anaerobic endurance capacity [34] is well-known. Nevertheless, in our study, for the first time, an attempt was made to link the effect of supplemental EPA + DHA to changes in OUEP and OUE@VAT. ...
Peak oxygen uptake (VO2peak) is one of the most reliable parameters of exercise capacity; however, maximum effort is required to achieve this. Therefore, alternative, and repeatable submaximal parameters, such as running economy (RE), are needed. Thus, we evaluated the suitability of oxygen uptake efficiency (OUE), oxygen uptake efficiency plateau (OUEP) and oxygen uptake efficiency at the ventilatory anaerobic threshold (OUE@VAT) as alternatives for VO2peak and RE. Moreover, we evaluated how these parameters are affected by endurance training and supplementation with omega-3 fatty acids. A total of 26 amateur male runners completed a 12-week endurance program combined with omega-3 fatty acid supplementation or medium-chain triglycerides as a placebo. Before and after the intervention, the participants were subjected to a treadmill test to determine VO2peak, RE, OUE, OUEP and OUE@VAT. Blood was collected at the same timepoints to determine eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in erythrocytes. OUE correlated moderately or weakly with VO2peak (R2 = 0.338, p = 0.002) and (R2 = 0.226, p = 0.014) before and after the intervention, respectively. There was a weak or no correlation between OUEP, OUE@VAT, VO2peak and RE despite steeper OUE, increased OUEP and OUE@VAT values in all participants. OUE parameters cannot be treated as alternative parameters for VO2peak or RE and did not show changes following supplementation with omega-3 fatty acids in male amateur endurance runners.
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... Supplementation of omega-3 polyunsaturated fatty acids (ω-3 PUFA) is frequent in elite athletes [132]. Overall, ω-3 PUFA are welltolerated and can improve exercise performance and minimize strenuous training-induced muscle dysfunction in athletes via their antioxidant and anti-inflammatory properties [133][134][135][136]. In this context, docosahexaenoic-(DHA)-rich fish oil supplementation (3 g daily for 60 days) in marathon runners beneficially affected lymphocyte function changes induced by the marathon race [137]. ...
... A study with patients with obesity supplemented with EPA and DHA for 8 weeks showed decreased plasma ADMA levels [29]. On the other hand, a study involving trained cyclists showed no changes in plasma ADMA level after three weeks of omega-3 fatty acid supplementation [30]. Other studies have shown that the ADMA level in response to other supplementation interventions is difficult to assess [31,32] due to disturbances resulting from amino acid metabolism/gluconeogenesis and various levels of skeletal muscle damage [33]. ...
It is not fully understood how supplementation with omega-3 fatty acids affects themetabolism of amino acids required for the bioavailability/synthesis of NO, i.e., L-arginine (L-arg), asymmetric dimethylarginine (ADMA), their metabolites, and the L-arg/ADMA ratio and their impact on running economy (RE) in runners. Thus, 26 male amateur endurance runners completed atwelve-week study in which they were divided into two supplemented groups: the OMEGA group (n = 14; 2234 mg and 916 mg of eicosapentaenoic and docosahexaenoic acid daily) or the MCT group (n = 12; 4000 mg of medium-chain triglycerides daily). At the same time, all participants followed an endurance training program. Before and after the 12-week intervention, blood was collected from participants at two time points (at rest and immediately post-exercise) to determine EPA and DHA inred blood cells (RBCs) and plasma levels of L-arg, ADMA, and their metabolites. RBC EPA and DHA significantly increased in the OMEGA group (p < 0.001), which was related to the resting increase in L-arg (p = 0.001) and in the L-arg/ADMA ratio (p = 0.005) with no changes in the MCT group. No differences were found in post-exercise amino acid levels. A total of 12 weeks of omega-3 fatty acid supplementation at a dose of 2234 mg of EPA and 916 mg of DHA daily increased levels of L-arg and the L-arg/ADMA ratio, which indirectly indicates increased bioavailability/NO synthesis. However, these changes were not associated with improved RE in male amateur endurance runners.
Long chain omega-3 polyunsaturated fatty acid (LC n-3 PUFA) supplements, rich in eicosapentaenoic acid and/or docosahexaenoic acid, are increasingly being recommended within athletic institutions. The wide range of doses, durations and study designs implemented across trials make it difficult to provide clear recommendations. The importance of study design characteristics in LC n-3 PUFA trials has been detailed in cardiovascular disease research and these considerations may guide LC n-3 PUFA study design in healthy cohorts. This systematic review examined the quality of studies and study design considerations used in evaluating the evidence for LC n-3 PUFA improving performance in physically trained adults. SCOPUS, PubMed and Web of Science electronic databases were searched to identify studies that supplemented LC n-3 PUFA in physically trained participants. Forty six studies met inclusion. Most studies used a randomised control design. Risk of bias, assessed using the design-appropriate Cochrane Collaboration tool, revealed that studies had a predominant judgment of ‘some concerns’, ‘high risk’, or ‘moderate risk’ in randomised controlled, randomised crossover, or non-randomised studies, respectively. A custom 5-point quality assessment scale demonstrated that no study satisfied all recommendations for LC n-3 PUFA study design. This review has highlighted that the disparate range of study designs are likely contributing to the inconclusive state of outcomes pertaining LC n-3 PUFA as a potential ergogenic aid. Further research must adequately account for the specific LC n-3 PUFA study design considerations, underpinned by a clear hypothesis, in order to achieve evidence-based dose, duration and composition recommendations for physically trained individuals.
The study of the metabolism of fatty acids (FAs), including essential n-3 polyunsaturated fatty acids (n-3 PUFAs), is of great interest in the practice of elite sports due to their significant role in the energy supply of the body and, in general, increasing physical performance (PP). Athletes (cross-country skiers), members of the national team of the Republic of Komi and Russia (boys, n = 36) and students as a control group (boys, n = 13) were examined. The level of consumption of different classes of FAs was assessed using the author's on-line service "Fatty Acids in Products." The FA profile in total plasma lipids was determined by gas chromatography. Analysis of the fat component of the diet revealed an increased consumption of saturated fats and n-6 PUFAs relative to the recommended norms in both groups. In students, the consumption of essential n-3 eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids was significantly lower compared to skiers (p = 0.013) and the recommended norm. A suboptimal fat diet was accompanied by an imbalance in the FA profile in the blood in both groups. Crosscountry skiers have significantly lower levels of saturated myristic (p = 0.000) and palmitic acids (p = 0.003), which are within the reference values. The proportion of essential n-3 linolenic acid in the blood plasma of crosscountry skiers is lower than that of students (p = 0.002) and 2.2 times lower than the norm. The level of EPA in the blood in both groups was also reduced, and in students was almost 3 times more pronounced than in skiers (p = 0.000). Thus, the consumption of n-3 PUFAs by athletes in accordance with the recommended norms does not cover their consumption for energy supply and physiological functions involved in intense physical exertion and reduce the aerobic performance of the body. The results of the study can be applied in optimizing the diet and increasing the functional reserves and physical qualities of athletes and students.
This study aims to analyze the acute effect of omega 3 supplementation on serum TNF-α levels, pain intensity, and muscle strength after high-intensity weight training. A total of 20 adult males with a BMI of 18.00-24.99 were enrolled in this study. Subjects were divided into 2 groups, namely (K1) with placebo and (K2) with omega 3 supplementation with a dose of 1000 mg (540 mg EPA and 360 mg DHA). The intervention was carried out 24 hours after high-intensity weight training. The data in this study were taken before and after the intervention. Measurement of serum TNF-α levels using a human ELISA kit, measurement of pain intensity using visual analog scale (VAS), measuring muscle strength using a leg dynamometer. The data analysis technique is used if the data is normally distributed, namely Paired t-test and Independent t-test, if the data has not normally distributed the analysis used is the Wilcoxon signed-rank test. Omega 3 supplementation significantly reduced serum TNF-α levels (p-0.035), significantly reduced pain levels (p-0.007), and did not significantly decrease the strength (p-0.100). Omega 3 supplementations can reduce serum TNF-α levels, pain intensity, and omega 3 supplementations can maintain muscle strength after high-intensity weight training as evidenced by the absence of a significant decrease in muscle strength after high-intensity weight training.
The growing prevalence of physical inactivity in the population highlights the urgent need for a more comprehensive understanding of how sedentary behaviour affects health, the mechanisms involved and what strategies are effective in counteracting its negative effects. Physical inactivity is an independent risk factor for different pathologies including atherosclerosis, hypertension and cardiovascular disease. It is known to progressively lead to reduced life expectancy and quality of life, and it is the fourth leading risk factor for mortality worldwide. Recent evidence indicates that uninterrupted prolonged sitting and short-term inactivity periods impair endothelial function (measured by flow-mediated dilation) and induce arterial structural alterations, predominantly in the lower body vasculature. Similar effects may occur in the cerebral vasculature, with recent evidence showing impairments in cerebral blood flow following prolonged sitting. The precise molecular and physiological mechanisms underlying inactivity-induced vascular dysfunction in humans are yet to be fully established, although evidence to date indicates that it may involve modulation of shear stress, inflammatory and vascular biomarkers. Despite the steady increase in sedentarism in our societies, only a few intervention strategies have been investigated for their efficacy in counteracting the associated vascular impairments. The current review provides a comprehensive overview of the evidence linking acute and short-term physical inactivity to detrimental effects on peripheral, central and cerebral vascular health in humans. We further examine the underlying molecular and physiological mechanisms and attempt to link these to long-term consequences for cardiovascular health. Finally, we summarize and discuss the efficacy of lifestyle interventions in offsetting the negative consequences of physical inactivity.
We aimed to investigate the long-term effect of daily Calanus oil supplementation on maximal oxygen uptake (VO 2 max) in healthy 30- to 50-year-old participants. The study was motivated by preclinical studies reporting increased VO 2 max and metabolic health with omega-3 rich Calanus oil. In a double-blinded study, 71 participants were randomized to receive 2 g/day of Calanus or placebo supplementation for a total of 6 months. The participants underwent exercise testing and clinical investigations at baseline, 3 months, and 6 months. Main study endpoint was change in VO 2 max from baseline to 6 months. Fifty-eight participants completed the 6-month test and were included in the final data analysis (age: Calanus, 39.7 [38.0, 41.4] and placebo, 38.8 [36.8, 40.9] years; body mass index: Calanus, 24.8 [24.0, 25.6] and placebo, 24.8 [23.7, 25.8] kg/m ² ; and VO 2 max: Calanus, 50.4 [47.1, 53.8] and placebo, 50.2 [47.2, 53.1] ml·kg ⁻¹ ·min ⁻¹ ). There were no between-group differences at baseline, nor were there any between-group differences in absolute (Calanus, 3.74 [3.44, 4.04] and placebo, 3.79 [3.44, 4.14] L/min) or relative VO 2 max (Calanus, 49.7 [46.2, 53.2] and placebo, 49.5 [46.0, 53.1] ml·kg ⁻¹ ·min ⁻¹ ) at 6 months (mean [95% confidence interval]). There were no between-groups change in clinical measures from baseline to 3 and 6 months. In conclusion, VO 2 max was unaffected by 6 months of daily Calanus oil supplementation in healthy, physically fit, normal to overweight men and women between 30 and 50 years old.
Increased muscle oxidative stress and inflammatory responses among athletes and has been reported consistently. In addition, it is well known that exhaustive and/or unaccustomed exercise can lead to muscle fatigue, delayed onset muscle soreness, and a decrement in performance. Omega-3 polyunsaturated fatty acids (PUFAs) have been shown to decrease the production of inflammatory eicosanoids, cytokines and reactive oxygen species, possess immunomodulatory effects, and to attenuate inflammatory diseases. While a number of studies have assessed the efficacy of omega-3 PUFA supplementation on red blood cell deformability, muscle damage, inflammation, and metabolism during exercise, only a few studies have evaluated the impact of omega-3 PUFA supplementation on exercise performance. It has been suggested that the ingestion of EPA and DHA of approximately 1-2 g per day, at a ratio of EPA to DHA of 2:1, may be beneficial in counteracting exercise-induced inflammation and for the overall health of an athlete. However, the human data is inconclusive as to whether omega-3 PUFA supplementation, at this dosage, is effective in attenuating the inflammatory and immunomodulatory response to exercise, and improve exercise performance. Thus, attempts should be made to establish an optimal omega-3 fatty acid dosage to maximise the risk/reward ratio of supplementation. It should be noted that high omega-3 PUFA consumption may lead to immunosuppression and prolong bleeding time. Future studies investigating the efficacy of omega-3 PUFA supplementation in exercise-trained individuals should consider using an exercise protocol of sufficient duration and intensity in order to produce a more robust oxidative and inflammatory response.
The aim of the present study was to test the hypothesis that the cardiovascular-protective effects of eicosapentaenoic acid (EPA) may be due, in part, to its ability to stimulate the AMP-activated protein kinase (AMPK)-induced endothelial nitric oxide synthase (eNOS) activation. The role of AMPK in EPA-induced eNOS phosphorylation was investigated in bovine aortic endothelial cells (BAEC), in mice deficient of either AMPKα1 or AMPKα2, in eNOS knockout (KO) mice, or in Apo-E/AMPKα1 dual KO mice. EPA-treatment of BAEC increased both AMPK-Thr172 phosphorylation and AMPK activity, which was accompanied by increased eNOS phosphorylation, NO release, and upregulation of mitochondrial uncoupling protein-2 (UCP-2). Pharmacologic or genetic inhibition of AMPK abolished EPA-enhanced NO release and eNOS phosphorylation in HUVEC. This effect of EPA was absent in the aortas isolated from either eNOS KO mice or AMPKα1 KO mice fed a high-fat, high-cholesterol (HFHC) diet. EPA via upregulation of UCP-2 activates AMPKα1 resulting in increased eNOS phosphorylation and consequent improvement of endothelial function in vivo.
Nitric oxide (NO) is a potent signalling molecule that influences an array of physiological responses. It was traditionally assumed that NO was derived exclusively via the nitric oxide synthase (NOS) family of enzymes. This complex reaction requires a five electron oxidation of L-arginine and is contingent on the presence of numerous essential substrates (including O2) and co-factors. Recently an additional, O2-independent, NO generating pathway has been identified, where nitrite (NO2 ) can undergo a simple one electron reduction to yield NO. NO2 is produced endogenously from the oxidation of NO and also from the reduction of dietary nitrate (NO3 ) by facultative bacteria residing on the tongue. Recent data show that dietary NO3 supplementation, which increases the circulating plasma [NO2 ], reduces the O2 cost of submaximal exercise in healthy humans. This finding is striking given that efficiency during moderate-intensity exercise has been considered to be immutable. There is evidence that the muscle ATP turnover at a fixed work rate is reduced and the mitochondrial P/O ratio is increased following NO3 supplementation, which offers important insights into the physiological bases for the reduced [Vdot] during exercise. NO3 supplementation has also been shown to improve exercise performance in both healthy and patient populations. Therefore, dietary NO3 supplementation may represent a practical and cost-effective method to improve exercise efficiency and exercise tolerance in humans. Given that a NO3 -rich diet may have numerous cardiovascular and other health benefits, dietary NO3 intake may have important implications for human lifelong health and performance.
Human beings evolved consuming a diet that contained about equal amounts of ω-6 and ω-3 essential fatty acids. Today, in Western diets, the ratio of ω-6 to ω-3 fatty acids ranges from approximately 10:1 to 20:1 instead of the traditional range of 1:1 to 2:1. Studies indicate that a high intake of ω-6 fatty acids shifts the physiologic state to one that is prothrombotic and proaggregatory, characterized by increases in blood viscosity, vasospasm, and vasoconstriction, and decreases in bleeding time. ω-3 fatty acids, however, have anti-inflammatory, antithrombotic, antiarrhythmic, hypolipidemic, and vasodilatory properties. Excessive radical formation and trauma during high-intensity exercise leads to an inflammatory state that is made worse by the increased amount of ω-6 fatty acids in Western diets, although this can be counteracted by eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). For the majority of athletes, especially those at the leisure level, general guidelines should include EPA and DHA of about 1 to 2 g/d at a ratio of EPA:DHA of 2:1.
Purpose of review:
Vascular function is recognized as an early and integrative marker of cardiovascular disease. While there is consistent evidence that the quantity of dietary fat has significant effects on vascular function, the differential effects of individual fatty acids is less clear. This review summarizes recent evidence from randomly controlled dietary studies on the impact of dietary fatty acids on vascular function, as determined by flow-mediated dilatation (FMD).
Recent findings:
Critical appraisal is given to five intervention studies (one acute, four chronic) which examined the impact of long-chain n-3 polyunsaturated fatty acid [eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] on FMD. In the acute setting, a high dose of long-chain n-3 polyunsaturated fatty acid (4.9 g per 70 kg man) improved postprandial FMD significantly, compared with a saturated fatty acid-rich meal in healthy individuals. In longer-term studies, there was limited evidence for a significant effect of EPA/DHA on FMD in diseased groups.
Summary:
The strongest evidence for the benefits of EPA/DHA on vascular function is in the postprandial state. More evidence from randomly controlled intervention trials with foods will be required to substantiate the long-term effects of EPA/DHA, to inform public health and clinical recommendations.
Flow-mediated dilation (FMD) is a noninvasive indicator of endothelial function and is routinely expressed as the percentage change in arterial diameter (FMD%) from a resting baseline (Dbase) to a postischemic peak (Dpeak). This expression is equivalent to the ratio of Dpeak/Dbase and is, therefore, dependent on important statistical assumptions, which have never been analysed in the context of FMD%. We aimed to investigate these assumptions, via a comparison of FMD between samples of children and adults, as well as to explore other approaches to scaling diameter change for Dbase. We found that FMD% did not scale accurately for interindividual differences in Dbase but, as expected, overestimated endothelial function for low Dbase and vice versa. We argue that this imprecise scaling of FMD% is predictable, not explained by physiology and is probably common. This problem is resolved by applying scaling principles, whereby the difference in diameter is the outcome and Dbase is a covariate in a logarithmic-linked generalized linear model. A specific allometric expression of FMD can be derived and we found this to be Dpeak/Dbase rather than a simple ratio in our particular dataset. We found that sample differences in endothelial function were inaccurate with FMD% versus our new allometric approach, and that FMD% misclassified participants into 'high' and 'low'cohorts, which has implications for prognostic-type studies. We conclude that the general use of FMD% could have led to biased comparisons of different conditions and/or populations in past studies. Our new approach to scaling FMD is flexible for different datasets and is not based on the current assumption that a percentage change is appropriate in all circumstances.
2004;7(1):48-56. Recent evidence suggests that omega-3 fatty acids from fish oil (FO) stimulate fat oxidation in liver and perhaps skeletal muscle. Our purpose was to examine the effect of an acute high-dose and a chronic low-dose of FO on fat oxidation during exercise. Seven recreationally active males (age 21-27 yr) jogged for 60 min at 60 % VO 2 max in three trials administered in random order: 1) no meal (NM), 2) 4 h following a high-fat meal (HFM), and 3) 4 h following an isocaloric HFM partly substituted with FO (HFM+FO). The FO supplement contained 60 % eicosapentaenoic acid, and 40 % docosahexaenoic acid. Subjects then supplemented 4 g/day of FO for 3 wk and while remaining on the supplementation regimen, repeated the same three trials in random order. Indirect calorimetry was used for the determination of oxygen consumption, respiratory exchange ratio, and energy expenditure from fat and carbohydrate. Heart rate, and rating of perceived exertion were also monitored for each test. The acute high-dose FO had no significant affect on fat use during exercise. In contrast, chronic supplementation significantly augmented total fat energy expenditure as compared to trials before supplementation in each of the three treatments versus trials prior to chronic supplementation (NM, 269.1 ± 49.8 v. 245.7 ± 36.2 Kcal, P = 0.009; HFM, 295.2 ± 40.2 v. 260.8 ± 36.4, P = 0.001; HFM+FO, 299.0 ± 38.7 v. 280.4 ± 35.9 Kcal, P = 0.002). These data suggest that chronic, but not acute FO supplementation enhanced the contribution of lipid during exercise in young active males.