Ergocalciferol and muscle damage after eccentric exercise
What it found
In 28 NASCAR pit crew athletes, six weeks of ergocalciferol (vitamin D2) raised blood levels of 25(OH)D2 but led to higher markers of muscle damage after a tough workout.
It made no difference to muscle function test scores.
What they found
Studies in people
Blood vitamin D changes
Six weeks of vitamin D2 raised serum 25(OH)D2 by 456% and lowered serum 25(OH)D3 by 21% compared to placebo. Total serum 25(OH)D did not change significantly.
Muscle function tests
There were no differences between the vitamin D2 and placebo groups in leg-back strength, hand grip, bench press to exhaustion, vertical jump, or 30-second cycling power.
Muscle damage markers
After the eccentric exercise, the vitamin D2 group had higher levels of myoglobin (252% increase vs 122%) and creatine phosphokinase at 24 hours (169% vs 32%) than the placebo group.
Muscle soreness
Delayed onset muscle soreness did not differ between the vitamin D2 and placebo groups after exercise.
Link to vitamin D2 rise
The rise in serum 25(OH)D2 was linked to the rise in myoglobin after exercise across all participants.
What the authors conclude
“In summary, the novel and unexpected finding of this randomized, double-blinded, placebo controlled study of 28 NASCAR pit crew athletes was that 6-weeks supplementation with vitamin D 2 increased serum 25(OH)D 2 , decreased serum 25(OH)D 3 , and amplified EIMD.”
Also in their conclusions
- They conclude that six weeks of vitamin D2 supplementation increased serum 25(OH)D2, decreased serum 25(OH)D3, and amplified muscle damage markers after eccentric exercise in these athletes.
- They say that if these results are confirmed, the reasons for the negative effects of vitamin D2 on muscle damage need to be explored.
- They advise further research to see if vitamin D2 supplementation amplifies muscle damage in athletes who are vitamin D deficient, especially compared with vitamin D3.
How it was done
The authors wanted to see if vitamin D2 supplements could improve muscle function and reduce muscle damage and soreness after eccentric exercise. No previous human study had looked at this.
They randomly split 28 NASCAR pit crew athletes into a vitamin D2 group (3800 IU per day) and a placebo group for six weeks. Before and after, they tested muscle function, then had everyone do 90 minutes of eccentric exercise and measured blood markers of muscle damage and soreness.
What it can’t tell you
- This was a small study of 28 athletes, so the results may not apply to other groups.
- The athletes were not vitamin D deficient, so the findings may not apply to people who are deficient.
- The study cannot show whether the higher muscle damage markers were caused by the rise in vitamin D2, the fall in vitamin D3, or both.
Who paid
- Authors work at
- Appalachian State University, USA
The paper
- Title
- Vitamin D2 supplementation amplifies eccentric exercise-induced muscle damage in NASCAR pit crew athletes
- 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
- Nieman DC, Gillitt ND, Shanely RA, Dew D, Meaney MP, Luo B (2013). Vitamin D2 supplementation amplifies eccentric exercise-induced muscle damage in NASCAR pit crew athletes. Nutrients. doi:10.3390/nu6010063Free full textPubMed 24362707DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error