There has been an increased interest in activating autophagy by exercise lately. But is it really true that physical exercise activates autophagy? If so, what kind of exercise is best for autophagy activation? And what does the research say?
This article will try to find answers to these questions.
Autophagy is a natural process that happens inside our body cells. It’s like a cleaning system that helps our cells eliminate waste and damaged components to keep them healthy.
Imagine that our cells are like tiny factories, constantly working and producing different molecules and structures. Over time, some components of these factories may become old or damaged, and they need to be removed so that the cell can function properly. The removal of those components is the responsibility of autophagy.
But how does autophagy do that?
Autophagy is a complicated process that requires a series of events culminating in degrading unwanted cellular components and recycling them back as reusable products.
In this process, the targeted components are first identified. Then, they are engulfed by a circular membrane-like structure called an autophagosome. The autophagosome formation is crucial, as the whole process can be destroyed without this step. The autophagosome carrying the cellular components fuses with the lysosome, which is the waste disposal unit of the cell. The lysosome contains enzymes that break down the contents of the autophagosome and release them as reusable products for energy production and building blocks.
Exercise – as the activator of autophagy
There has been increasing interest in finding natural ways of activating autophagy. Besides fasting and calorie restriction, the widely known methods, physical exercise is another way of activating autophagy.
Physical exercise as an autophagy activator has long been underestimated but has gained tremendous attention lately. Numerous studies have provided evidence that autophagy is activated in different parts of the body in response to exercise. This suggests that physical exercise could be an effective way of dealing with diseases caused by the loss of autophagy. This’s why many researchers consider physical exercise as a form of “autophagy pills” in the treatment of some severe diseases like neurodegenerative, heart, and metabolic disorders.
But why does autophagy activate during exercise?
Whenever we do physical exercise, our body cells experience stress. This’s called energetic stress, in which the cell is under intense demand for energy generation. The muscles that are most commonly affected by this stress are those from the skeletal, heart, brain, and liver. Researchers have noticed that autophagy is elevated in muscles from these organelles during physical exercise, and it remains elevated hours after the cessation of exercise, indicating that autophagy activation is basically the body’s adaptive response to exercise. In this adaptive response, autophagy degrades and recycle cellular contents so that cell can use them for energy production. Simply put, autophagy activation better prepares the body to cope with stressful events caused by physical exercise.
What kind of exercise is best for autophagy activation?
It’s now well-known that physical exercise is a strong activator of autophagy. However, not all modes of exercise can promote autophagy. Research suggests that autophagy induction can be regulated according to the type, duration, and intensity-dependent manner.
Some forms of exercise enhance autophagic activity, which could have beneficial effects on the brain. Others boost the autophagy process, that could promote longevity. For example, a study published in the Journal of CNS Neuroscience and Therapeutics showed that running exercise 5 days per week for a total of 8 weeks in mice increased the expression of genes associated with autophagy. Such enhanced autophagy improves brain functions and helps in delaying the progress of brain diseases.
Other studies reported that swimming can boost the autophagy process, and this can slow down the aging process. A study that appeared in the Journals of Gerontology reported that 10-week swimming exercise in older rats promoted the activation of autophagy. In these rats, there was a mitochondrial improvement in parts of the brain responsible for learning and memory functions, suggesting that exercise-indued autophagy activation could improve the brain’s cognitive functions in the aged population.
Despite these and other well-reported animal studies, there is still uncertainty about the role of exercise as an autophagy activator in humans. Some studies showed activation of autophagy, while others observed no changes following exercise.
A recently published review paper has delved into this issue and provides a more conclusive picture of the autophagic response to exercise in humans. The study, published in the Journal of Autophagy, systematically accessed online databases to search for the human studies published (until September 2022) to explore the autophagic response to different exercises. The researchers of the study carefully examined the results of 26 studies. In these studies, they looked into changes in the autophagy markers in muscles and blood samples from participants involved in different forms of exercise, like acute bouts of exercise, long-term training (3–21 weeks), moderate to vigorous-intensity endurance, resistance, and mixed-type exercise. They concluded that physical exercise probably regulates autophagy in an exercise modality- and a tissue-dependent manner in humans. They stated that long-term resistance training is the recommended form of exercise for boosting autophagy in humans.
Conclusion
Physical exercise does activate autophagy. And this activation is essential for the body to cope with the stress that appears during and after the exercise. Researchers think that this way of autophagy activation can be used as a potential therapeutic option for treating some chronic diseases. Regarding the type of exercise, long-term resistance training is probably the best for achieving autophagy.
