However, too much of a good thing may be bad for you. New studies suggest that too much exercise may be harmful to our heart health. In 2008, the Department of Health and Human Services recommend that people participate in 150 minutes of moderate intensity exercise a week. One study that followed athletes over 25 years showed that people who exercised too much, which was defined as three times the national physical activity guidelines, had a higher risk of developing calcium buildup in the arteries. This is a risk factor for developing heart disease. Another study that followed women over an average period of 9 years showed that women who exercised moderately (2-3 times a week) experienced a lower risk of developing heart disease compared to both women who were inactive and women who exercised strenuously everyday.
Intense Exercise May Accelerate the Aging Process
In addition to the negative effects of intensive exercise on cardiovascular health, another recent study suggests that strenuous physical activity may also be associated with accelerated aging. Scientists compared the epigenetic age (which is the biological age that reflects a person's experiences and exposures over a lifetime) of elite athletes to that of their healthy counterparts. By measuring the alterations of particular genetic sequences, the scientists observed that the athletes were on average 3-6 years older than people of the similar chronological age that were not athletes. While it has been commonly accepted that exercise helps increase our lifespan, this study indicates that the relationship between epigenetic age and mortality may be more complicated than previously thought.
After prolonged exercise, such as a 25-mile run, the body changes its metabolism, with a resulting increase in free radicals, atoms that can cause permanent damage to your cells and can also speed up the ageing process.
Free radicals, which are also created by external factors such as pollutants, ultraviolet light or cigarette smoke, are highly reactive and attack nearby healthy molecules, including your collagen and DNA. Collagen damage will make your skin look older.
Free radicals attack healthy molecules until they are mopped up by a radical scavenger or an antioxidant. It has been calculated that under normal circumstances, each of our 100 trillion cells gets hit by 10,000 free radicals per day.
Antioxidants convert the free radicals back into a good molecules. To keep up your intake of antioxidants - sources include vitamins C and E - eat plenty of fruit and vegetables or take supplements.
We know that running can help prevent arthritis, but there's a limit. A British Medical Journal study of 2,049 Finnish athletes found that endurance and sports athletes had a higher incidence of osteoarthritis, as a result of increased wear and tear on their joints.
https://www.standard.co.uk/hp/front/can-exercise-age-you-7292333.html
https://www.mydnage.com/blog/can-too-much-exercise-accelerate-biological-aging