How does exercise slow aging?

Dr Merlin Thomas

Merlin Thomas is a physician and a scientist. His research laboratory is at the JDRF/ Danielle Alberti Memorial Centre for the study of Diabetes Complications at the Baker IDI Heart and Diabetes Institute in Melbourne.
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The majority of adults do not get enough physical activity to optimize health and improve their quality life. If we are sedentary, the risk of premature death and disease increases to the same extent as being a smoker. By contrast, regular activity not only increases level of fitness and health, but also has been shown to increase our lifespan by approximately 3 to 5 years. Equally, we can have the best diet, eat handfuls of supplements and have a positive attitude, but if we are sedentary many of these benefits may be lost.  But how does exercise work for us?

Exercise burns calories

Exercise burns calories that would otherwise be deposited as fat around our abdominal area. Consequently, regular exercise is an important means to reduce our abdominal fat levels and assist with weight control but it also improves the proportion of muscle tissue to body fat – a change that reverses the effect of aging. However, the value of regular exercise is not just about reducing body fat; the effects are wide ranging, slowing down the normal aging process in many body systems.

Exercise is anti-aging

Physical activity modifies many of the factors that contribute to aging and disease, including heart disease, diabetes, dementia, depression, osteoporosis and cancer. For example, exercise reduces the effects of free radicals, inflammation, AGEs, stress and assists in the reduction of high cholesterol, glucose and blood pressure levels. Exercise is also able to modify hormones that impact the aging process, including reducing blood insulin levels (and insulin resistance), and increasing the anti-aging hormones, growth hormone, testosterone and DHEA.

Exercise increases reserve

Regular and progressively increasing levels of different types of exercise or ‘physical training’, stimulates specific body systems which results in adaptations to its natural defense pathways. These adaptations we call ‘getting fit’. For example, if the heart and circulatory system is overloaded by a regular walking program, the capacity of this system also increases, so we can do more with less effort and fatigue. Regular exercise will also improve the body’s repair and regeneration mechanisms that protect against future damage during exercise.

Exercise is protective

If muscles are progressively overloaded during resistance training will adapt to become bigger and stronger. Stronger muscles will preserve capacity to carry out daily tasks and maintain our quality of life when we are older. Strength training also increases the bone strength, thus reducing our risk of a fracture during a fall. Increased levels of endurance, strength and balance increase the threshold for disability and dependence as we age. Increases in physical activity and functional capacity are increasingly useful as we get older.  Other protective mechanisms also improve. Although exercise releases free radicals, the higher antioxidant levels that result from becoming fit, means that oxidative stress is also lower in the long-term. Being fit also makes us think better. Exercise stimulates the growth and development of brain cells, increasing their capacity for learning and memory and slowing the loss in mental performance and diseases associated with the aging process.