We’ve all been told how good exercise is, and most of us can certainly see and feel the benefits of it! Scientists have proven significant benefits in all sorts of populations and applying all sorts of different exercises. However, only recently are they starting to understand the specific benefits at a cellular level, particularly in helping slow the effects of ageing.
A recent study set out to determine this. As we age, our cells become a little more damaged over time. Of significance, the damage accrued by cells in older muscles is especially severe, because they do not regenerate easily and they become weaker as their mitochondria, which “energy stations” of the cells, diminish in vigour and number.
Researchers tested 72 individuals some of which were 30 years of age, and some aged 64 years or more. After baseline measures were established for their aerobic fitness, their blood-sugar levels and the gene activity and mitochondrial health in their muscle cells, the volunteers were randomly assigned to a particular exercise regimen; either vigorous weight training several times a week, brief interval training (HIIT) 3 times a week, or combined moderate cardio a few times a week and weights training on other days. A fourth group did not exercise.
After 12 weeks, the lab tests were repeated. In general, everyone experienced improvements in fitness and an ability to regulate blood sugar. There were some unsurprising differences: The gains in muscle mass and strength were greater for those who exercised only with weights, while interval training had the strongest influence on endurance. This information is quite well-known these days.
But more unexpected results were found in the biopsied muscle cells. Among the younger subjects who went through interval training, the activity levels had changed in 274 genes, compared with 170 genes for those who exercised more moderately and 74 for the weight lifters. Among the older cohort, almost 400 genes were working differently now, compared with 33 for the weight lifters and only 19 for the moderate exercisers.
Many of these affected genes, especially in the cells of the interval trainers, are believed to influence the ability of mitochondria to produce energy for muscle cells; the subjects who did the interval workouts showed increases in the number and health of their mitochondria, particularly those who did HIIT.
The authors concluded that the decline in the cellular health of muscles associated with aging was “corrected” with exercise, especially if it was intense. In fact, older people’s cells responded in some ways more robustly to intense exercise than the cells of the young did — suggesting, he says, that it is never too late to benefit from exercise.
Enhanced Protein Translation Underlies Improved Metabolic and Physical Adaptations to Different Exercise Training Modes in Young and Old Humans; Volume 25, Issue 3, p581–592, 7 March 2017