Four weeks of omega-3 supplementation does not improve cycling time trial performance in trained cyclists

Objectives

This study examined whether omega-3 polyunsaturated fatty acid (n-3 PUFA) supplementation lowered the heart rate (HR), rating of perceived exertion (RPE) and oxygen uptake (V̇O₂) and accordingly improved cycling performance in a time trial.

Design

In a randomised, crossover, double-blind study, trained male cyclists (n = 10) were supplemented for 4 weeks with n-3 PUFA (5.7 g/day of eicosapentaenoic acid (EPA) and docosahexaenoic (DHA)) and 4 weeks with placebo (6g olive oil), with a 4-week washout period.

Methods

Cycling performance trials (45 min preload at 70% maximal work rate (Wmax) followed by 15 min time trial) were carried out prior to and following both supplementation periods. Fatty acid composition of blood total lipids was analysed prior to and in response to supplementation.

Results

Whole blood n-3 PUFA (% total fatty acids) increased from 1.67% (SD = 0.99%) to 3.72% (SD = 1.22%) (p < 0.05) following 4 weeks n-3 PUFA supplementation. Submaximal measures of V̇O₂, HR, respiratory exchange ratio (RER) and RPE were unaffected by supplementation. Time trial performance (mean power W) was unchanged by n-3 PUFA (pre 239 W, SD = 34 W vs post 243 W, SD = 33 W), as were measures of V̇O₂, HR, RER and RPE during the time trial.

Conclusions

High dose n-3 PUFA supplementation for 4 weeks did not improve cycling performance or attenuate the physiological variables usually associated with improved cycling performance, i.e. V̇O₂ and HR, in a repeated-measures, placebo-controlled, crossover design study. It is possible that the exercise protocol used in the study was of insufficient intensity for the n-3 PUFA to show beneficial affects due to the highly trained nature of the cyclists.