As we get older, we tend to notice the external changes, such as wrinkles and less strength, and we don’t think about what happens at the level of our individual cells. They change as well, and today we present the best way to slow or even reverse some aging changes within our muscles cells—HIIT exercise.
Muscle cells, more than any other, need “fuel” to function well, to contract. Within our cells, there are tiny structures called mitochondria (pictured in the photo above), that act as fuel factories for the cells, that supply the energy our cells need. Muscle cells need lots of energy, and as we get older, our mitochondria get less efficient at making “fuel”, and our muscles do not function as well.
While scientists know that exercise decreases disease and disability overall, not as much is known about how exercise changes our cells. A common belief amongst cell physiologists is that if we can somehow keep our mitochondria functioning well as we age, our cells (including muscle cells) will function better as we get older.
The research on exercise and mitochondria
Researchers from the prestigious Mayo Clinic (Minnesota, USA) published an elegant study to determine which type of exercise would keep our mitochondria healthiest as we get older. With healthier mitochondria, we would better keep our muscle strength as well.
They recruited 72 healthy, sedentary men and women. They found volunteers in 2 ages ranges: younger people (under 30) and older people (over 64). They randomly divided all of them into 4 groups. For the next 12 weeks, they had each group do a specific exercise program 3 times a week. One group did vigorous weight training, the second group did High Intensity Interval Training (HIIT)—consisting of 4 minutes of rapid pedaling on a stationary bike followed by 3 minutes of effortless pedaling (this sequence was repeated 3 more times). The third group rode stationary bikes at a moderate pace for 30 minutes, with alternate days of easy weight lifting. The fourth group did not exercise.
All the volunteers had extensive blood tests at the beginning and end of the study. They also all submitted to muscle biopsies, to study their muscle cell mitochondria, including the genes within their mitochondria.
The results showed HIIT best
The group that just did the weight lifting, unsurprisingly, had the best growth in muscle mass, but the HIIT group had the best improvement in endurance. The HIIT group also had the best improvement in their mitochondrial genes as well. The HIIT group had healthiest functioning and greatest number of mitochondria at the end of the study.
These findings were consistent for the young group as well as the older group. But surprisingly, the older group showed a much better improvement from HIIT training than did the young group. According to the senior author of the study, Dr. Sreekumaran Nair “the decline in the cellular health of muscles associated with aging was ‘corrected’ with exercise, especially if it was intense” and “older people’s cells responded more strongly to intense exercise than the cells of the young did”.
This suggests that if you want to keep your muscle cells in optimal condition as you age, you should consider HIIT training. It seems the important factor is that some of the exercise you do is “intense”. Of course, check with your doctor before you start such an exercise program.
Probably the best approach is a combination of HIIT on some days with weight training on other days. In this way, your muscle cells will stay younger, and you will keep good muscle mass. This study also shows: it’s never too late to start exercising!
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