Olive leaf extract modified muscle mitochondrial responses to both moderate and sprint exercise. Digest
How muscles respond to exercise largely depends on intensity, and researchers are testing whether targeted nutrients can influence that process. A new study examined whether an olive leaf extract rich in the polyphenol oleuropein could alter muscle responses to moderate cycling or sprint interval exercise.
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The crossover trial included 22 healthy, physically active young men who were not following a structured training program. Participants were assigned to either moderate-intensity continuous exercise (1 hour of cycling at 50% maximal aerobic power) or sprint interval exercise (six 30-second all-out cycling sprints). Within each exercise modality, participants completed sessions after taking either placebo or olive leaf extract (250 mg standardized to 40% oleuropein, providing 100 mg of oleuropein). Researchers collected several small muscle samples from the thigh to measure pyruvate dehydrogenase activity (PDH, an enzyme complex that helps muscles convert carbohydrate fuel into energy inside mitochondria), along with changes in gene expression and protein levels related to oxidative phosphorylation (OXPHOS, the main process mitochondria use to produce energy).
- After moderate exercise, PDH activity increased only with olive leaf extract.
- After sprint interval exercise, PDH activity rose with exercise itself, but olive leaf extract did not further increase it.
- Moderate exercise alone increased the gene-expression responses in OXPHOS 24 hours later, and olive leaf extract amplified this response.
- Sprint exercise alone reduced the activity of the OXPHOS gene-expression pathway right after exercise and 24 hours later, while olive leaf extract increased this pathway at both time points.
- During the first sprint, participants maintained their power better after taking olive leaf extract: the drop from the first 5 seconds to the last 5 seconds of the sprint was about 25% lower than with placebo. Initial sprint power did not differ, and the extract did not improve the overall decline in mean power across all six sprints.
- Olive leaf extract did not reduce muscle fatigue, as muscle force loss and its recovery over 24 hours were not improved.
The results suggest that olive leaf extract interacts with exercise differently depending on intensity. During moderate exercise, olive leaf extract may have strengthened the muscle's mitochondrial response. During sprint exercise, that same pathway may already be near its limit, leaving less room for the extract to have an additional effect. Even so, the extract still changed how genes linked to mitochondrial function responded, pointing to other mechanisms that were not directly measured.
The study was small, involved only healthy young men, tested just one dose of the supplement, and tracked responses for only 24 hours. Still, the findings suggest that olive leaf extract may enhance some acute mitochondrial responses to exercise in muscle. In Q&A #64, I share my thoughts on using olive leaf extract to support cardiovascular health.