Can a standard dose of eicosapentaenoic acid (EPA) supplementation reduce the symptoms of delayed onset of muscle soreness?

Abstract

Background: Unaccustomed exercise can result in delayed onset of muscle soreness (DOMS) which can affect athletic performance. Although DOMS is a useful tool to identify muscle damage and remodelling, prolonged symptoms of DOMS may be associated with the over-training syndrome. In order to reduce the symptoms of DOMS numerous management strategies have been attempted with no significant effect on DOMS-associated cytokines surge. The present study aimed to investigate the acute and chronic effects of a 2 × 180 mg per day dose of eicosapentaenoic acid (EPA) on interleukin-6 (IL-6) mediated inflammatory response and symptoms associated with DOMS.

Methods: Seventeen healthy non-smoking females (age 20.4 ± 2.1 years, height 161.2 ± 8.3 cm and mass 61.48 ± 7.4 kg) were randomly assigned to either placebo (N = 10) or EPA (N = 7). Serum IL-6, isometric and isokinetic (concentric and eccentric) strength, and rating of perceived exertion (RPE) were recorded on four occasions: i-prior to supplementation, ii-immediately after three weeks of supplementation (basal effects), iii-48 hours following a single bout of resistance exercise (acute training response effects), and iv-48 hours following the last of a series of three bouts of resistance exercise (chronic training response effects).

Results: There was only a group difference in the degree of change in circulating IL-6 levels. In fact, relative to the first baseline, by the third bout of eccentric workout, the EPA group had 103 ± 60% increment in IL-6 levels whereas the placebo group only had 80 ± 26% incremented IL-6 levels (P = 0.020). We also describe a stable multiple linear regression model which included measures of strength and not IL-6 as predictors of RPE scale.

Conclusion: The present study suggests that in doubling the standard recommended dose of EPA, whilst this may still not be beneficial at ameliorating the symptoms of DOMS, it counter intuitively appears to enhance the cytokine response to exercise. In a context where previous in vitro work has shown EPA to decrease the effects of inflammatory cytokines, it may in fact be that the doses required in vivo is much larger than current recommended amounts. An attempt to dampen the exercise-induced cytokine flux in fact results in an over-compensatory response of this system.

Figure 1

Resistance exercise, A - leg flexion, B - leg extension, C - straight leg dead lifts, D - walking lunges (Authorised use of photos from a study participant, personal communication, April 26 2010).

Figure 2

EPA and placebo group changes in isometric (A) concentric (B) eccentric torque (C) and RPE pain scale (D) at B1 (1^st baseline), B2 (2^nd baseline i.e. after three weeks of supplementation), S1 (after one bout of eccentric exercises) and S3 (after three bouts of eccentric exercises). Data are mean ± SEM. * indicates significant difference (P ≤ 0.05).

Figure 3

Changes in IL-6 mediated inflammation for EPA and placebo groups for B1 (1^st baseline), B2 (2^nd baseline i.e. after three weeks of supplementation), S1 (after one bout of eccentric exercises) and S3 (after three bouts of weekly eccentric exercises). * indicates a significant difference (P ≤ 0.05). A repeated measures ANCOVA shows a significant (P = 0.002) main effect of time (differences between B1 to S1, and B1 to S3) as well as an interaction between time and group (P = 0.020). Data are mean ± SEM.