Olive leaf extract modified muscle mitochondrial responses to both moderate and sprint exercise.

Mitochondria help muscle convert fuel into usable energy, and exercise intensity shapes how these systems respond after a workout. Researchers tested whether oleuropein-based olive leaf extract, a standardized extract rich in a polyphenol found in olive leaves, could alter muscle responses to moderate cycling or sprint interval exercise.

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The randomized, double-blind, placebo-controlled 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 bouts). Within each exercise modality, participants completed sessions with either placebo or olive leaf extract, taken 30 minutes before exercise. The extract provided 250 milligrams of olive leaf extract standardized to 40% oleuropein, including 100 milligrams of oleuropein. Researchers collected small biopsies from the vastus lateralis, a thigh muscle, before exercise, immediately after exercise, and 24 hours later, and used them to analyze muscle energy-related enzymes, gene activity, and protein changes.

• After moderate exercise, olive leaf extract led to a greater increase in PDH activity than placebo. PDH is an enzyme found in muscle and many other cells that helps convert carbohydrate-derived fuel into a form that mitochondria can use to produce energy.
• After sprint interval exercise, PDH activity rose with exercise itself, but olive leaf extract did not further increase it.
• Moderate exercise alone increased the mitochondrial gene-expression responses in oxidative phosphorylation 24 hours later, and olive leaf extract amplified this pathway response. Oxidative phosphorylation refers to the mitochondrial process that produces most cellular energy.
• Sprint exercise alone downregulated oxidative phosphorylation gene expression immediately after exercise and at 24 hours, 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 after exercise. Olive leaf extract did not reduce muscle fatigue after the workout. The maximum force participants could produce on demand declined after exercise and recovered by 24 hours, with no difference between groups

The results suggest that olive leaf extract interacts with exercise differently depending on intensity. During moderate exercise, it may boost an early step in how muscle ramps up energy production, which could also help explain the stronger mitochondrial gene activity seen a day later. 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 also found changes in gene activity linked to inflammation and how cells handle damaged or misfolded proteins. However, these findings were based on changes in gene expression only, and the researchers did not directly measure inflammatory molecules or the actual activity of these processes.

The study was small, included only healthy young men, tested a single acute dose, and followed participants for only 24 hours. Still, the findings suggest that combining olive leaf extract with regular exercise could be a promising way to enhance muscle energy responses. In Q&A #64, I share my thoughts on using olive leaf extract to support cardiovascular health.