We know the benefits of effort for the heart and muscles. A systematic review published in August 2026 looks at a more discreet family of messengers, made directly by mitochondria, which seem to rise after exercise. A promising lead to follow.
Messengers made in the power plant
Mitochondria do more than produce energy. They also make small proteins, called mitochondrial-derived peptides, which circulate in the blood and send signals to other organs. The most studied are humanin and MOTS-c. They take part in energy balance, insulin sensitivity and the cells' response to stress.
What exercise changes
A team from Indonesia and Turkey examined nine studies, published between 2016 and 2025, that measured these peptides before and after exercise. Most reported a trend towards higher levels after exercise. The finding fits a known idea: a working muscle sends signals to the whole body, and mitochondria are part of that conversation.
Another study, published in June 2026 in Medicine and Science in Sports and Exercise, points the same way from a different angle. In 43 adults, the better the cardiorespiratory fitness, the better the mitochondria of their immune cells performed. This is an association between two measures.
A lead to follow
The review covers nine studies with different protocols: length of effort, intensity, type of exercise. It presents these peptides as a lead that could contribute to the benefits of exercise. It links their action to energy balance and insulin sensitivity.
What this changes for you
Nothing new in practice: the recommendations stay the same. Moving regularly, combining endurance and muscle strengthening, and limiting long periods of sitting remain the basics. What changes is the understanding. Exercise protects not only the heart and muscles: it also stimulates the power plants inside each cell. This is a good reason to aim for regularity rather than performance.
Key takeaways
- Mitochondria make small proteins, including humanin and MOTS-c.
- Their level tends to rise after exercise, according to most of the studies reviewed.
- Nine studies reviewed, with varied protocols.
- Regular effort remains the lever, within reach of everyone.
Sources
- Ayubi N, Wibawa JC, Kurnaz M, Komaini A. Mitochondrial-derived peptides (MDPs) activated by physical exercise as therapeutic targets for metabolic disorders: a systematic review. Physiology International, 2026. https://doi.org/10.1556/2060.2026.00863
- Crane JC, Hodgman CF, Maddux RM, et al. The Impact of Cardiorespiratory Fitness on Cytotoxic T Cell Metabolism and Function. Medicine and Science in Sports and Exercise, 2026. https://doi.org/10.1249/MSS.0000000000004063
