Bilberry juice and muscle soreness after a half marathon
What it found
In 19 runners, drinking bilberry juice before and after a half marathon led to slightly more muscle soreness and a likely harmful rise in a marker of inflammation, compared with a placebo drink.
The authors call these results unexpected and preliminary.
What they found
Studies in people
Muscle soreness
Right after the race, the bilberry juice group had a possibly harmful greater increase in muscle soreness than the placebo group (11.6% difference). At 24 and 48 hours after the race, the differences between groups were unclear or trivial.
Inflammation (CRP)
From before the race to 24 hours after, bilberry juice led to a likely harmful increase in C-reactive protein compared with placebo. At 48 hours, the effect was possibly harmful. At other time points, differences were unclear or trivial.
Muscle damage (CK)
Creatine kinase rose after the half marathon in both groups. The differences between bilberry juice and placebo were unclear at every time point except from baseline to pre-race, where bilberry juice had a possibly harmful effect on reducing muscle damage.
Other findings
Bilberry juice composition
Each 200 ml serving of bilberry juice contained 744.14 mg of total phenols and 80.04 mg of total anthocyanins.
What the authors conclude
“Despite being a rich source of antioxidant and anti-inflammatory phytochemicals, BJ evoked small to moderate increases in exercise-induced DOMS and CRP.”
Also in their conclusions
- They conclude that consuming bilberry juice for 5 days before and 2 days after a half marathon may evoke small to moderate transient increases in muscle soreness and inflammation in recreationally trained runners.
- They say their surprising results require confirmation in a larger study, which should also determine whether the transient detrimental changes result in adverse functional changes in muscle strength and recovery.
How it was done
Fruits rich in polyphenols, like tart cherry, have been reported to reduce exercise-induced muscle damage and soreness. The authors wanted to see if bilberry juice, which is also rich in polyphenols, would do the same in runners.
They recruited 21 recreationally trained runners (16 men, 5 women) who were about to run the Sheffield Half Marathon. For 5 days before the race, on race day, and for 2 days after, the runners drank either 2 x 200 ml of bilberry juice or an energy-matched control drink. The researchers measured muscle soreness, creatine kinase (a marker of muscle damage) and C-reactive protein (a marker of inflammation) at several time points. Data from 19 runners were analysed.
What it can’t tell you
- The study was small (19 runners analysed) and the authors note that a larger sample size is needed to confirm the results.
- The study did not measure muscle strength or function, so it cannot show whether the increases in soreness and inflammation affected recovery or performance.
- The results are specific to this group of recreationally trained runners and this half marathon, so they may not apply to other people or other types of exercise.
Who paid
- Conflicts
- The authors declare no competing interests.Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
- Authors work at
- Sheffield Hallam University, UK
The paper
- Title
- Effect of bilberry juice on indices of muscle damage and inflammation in runners completing a half-marathon: a randomised, placebo-controlled trial
- Type
- Randomised controlled trial
- Evidence
- Studies in people
- Summarised from
- Full text
- Licence
- CC BY. Words in quotation marks are the authors’; the rest is our summary.
- Cite
- Lynn A, Garner S, Nelson N, Simper TN, Hall AC, Ranchordas MK (2018). Effect of bilberry juice on indices of muscle damage and inflammation in runners completing a half-marathon: a randomised, placebo-controlled trial. Journal of the International Society of Sports Nutrition. doi:10.1186/s12970-018-0227-xFree full textPubMed 29743826DOI
Summary written 29 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error