Can intense exercise actually make you age faster?

Regular physical activity slows ageing rather than accelerating it. A large randomised study with more than 5,000 participants with type 2 diabetes showed that an intensive programme of increased exercise and weight loss reduced the accumulation of chronic diseases over eight years by approximately 9%. That is the opposite of accelerated ageing.

There is, however, a nuance when it comes to intensive exertion in the short term. Immediately after a hard workout, the amount of glutathione (an antioxidant produced by the body) in the blood temporarily drops. This reflects increased consumption of antioxidants during exercise, because muscles produce more free radicals at that point. Whether this recoverable dip is also structurally harmful cannot be determined from the available research. People who train regularly have, on average, higher glutathione levels than those who do not exercise, which suggests that the body adapts.

For vascular ageing there is a specific caveat. In older people with obesity, aerobic training alone (four times per week, twenty weeks) had no measurable effect on the stiffness of the large arteries. Only the combination of training with moderate calorie reduction, resulting in approximately eight kilograms of weight loss, led to arteries that were 21% more flexible and a pulse wave velocity that was 8% lower. Exercise without weight loss is therefore insufficient for vascular health in people with severe obesity.

Being inactive is clearly worse. Inactivity accelerates muscle loss and worsens quality of life, both in normal ageing and in chronic disease. That muscle loss is also associated with a receptor in muscle tissue that becomes more active with ageing and drives inflammatory-like processes in muscles; this mechanism is independent of exercise itself. The conclusion remains: exercise is protective, not harmful, although for vascular health in people with excess weight the weight loss that accompanies exercise also plays a role.