Oleuropein-based olive leaf extract enhances muscle mitochondrial bioenergetics response to moderate - but not...

Sprint interval exercise (SIE) induces skeletal muscle mitochondrial adaptations that are comparable to, or greater than, those observed with moderate-intensity continuous exercise (MICE), despite requiring a lower training volume. Previous work has shown that these adaptations are at least partly mediated by enhanced mitochondrial bioenergetics, including increased mitochondrial Ca²⁺ uptake and resulting pyruvate dehydrogenase (PDH) activation. In parallel, the natural compound oleuropein from olive leaf extract (OLE) promotes mitochondrial Ca²⁺ uptake and activates PDH in mouse skeletal muscle. Here, we tested the hypothesis that OLE intake would activate PDH and potentiate mitochondrial adaptations in human skeletal muscle during either MICE or SIE. In a crossover, double-blind study, healthy males performed MICE (1 h at 50% maximal aerobic power, n = 11) or SIE (6 × 30 s all-out sprints with 4 min recovery, n = 10). Knee extensor neuromuscular tests and vastus lateralis muscle biopsies were performed before, immediately after and 24 h after SIE or MICE. OLE improved the decline of power output during the first sprint in SIE and reduced heart rate during MICE but did not affect knee extensor fatigability after both exercise modalities. Transcriptomic analyses revealed an effect of OLE on the mitochondrial and inflammatory response after MICE and SIE, while OLE increased PDH activity in combination with exercise only following MICE. Together, these results suggest that OLE modulates skeletal muscle response to exercise and pave the way for future investigations aiming to investigate the chronic effect of combining OLE and exercise training. KEY POINTS: Previous studies have shown that oleuropein increases mitochondrial calcium uptake in preclinical models and that mitochondrial calcium uptake contributes to skeletal muscle mitochondrial adaptations in response to maximal intensity exercise in humans. Olive leaf extract (OLE) increases the activity of pyruvate dehydrogenase, a proxy of mitochondria calcium uptake, when combined with moderate-intensity exercise. Combining moderate-intensity continuous exercise and sprint interval exercise with OLE enhances the mitochondrial response at a transcriptional level. OLE enhances skeletal muscle mitochondrial response to acute exercise, paving the way for investigating its effect in combination with chronic exercise training protocols.