We know that exercise helps improve depression, anxiety, cognitive function, the risk of progression of Alzheimer's disease and sleep. Exercise causes an endorphin rush causing us to feel good. It also increases the amount of serotonin and melatonin in the brain, improving depression and anxiety and improving sleep. Exercise has been identified as a key intervention in brain health, improving cognitive function and the risk of Alzheimer's. These benefits are in part derived from improved cerebrovascular health, reductions in blood pressure and improved brain perfusion. Exercise is a good stress reliever and helps us pay off the "adrenaline debt" that the stress of our modern lives imposes on our hypothalamic pituitary adrenal axis.
Exercise in the form of resistance training can help strengthen muscles which in turn can help reduce the pain of arthritis. Aerobic training can also reduce pain and improve wellbeing not only by the endorphin rush, but also by aiding in weight loss, which in and of itself has been shown to reduce pain. It is important however to engage in boom-and-bust activities, but rather to pace oneself and gradually increase exercise loads. Overexercising as dangerous as not exercising. Weight bearing and load bearing exercises are also known to stimulated bone growth and inhibit bone loss, thereby preventing the progression of osteoporosis, a thinning of the bones that leads to fragility fractures.
Exercise reduces cancer.
We know that exercise reduces the risk of the following cancers: bladder; breast; colon; endometrium; oesophageal; stomach; and lung cancer. For breast and colon cancer exercise has been found to reduce the risk of developing these cancers by as much as 30%. These effects may result from an improved immunosurveillance that occurs in response to the beneficial stimulatory effect that exercise has on natural killer cells and T-cells which are an essential part of our immune system. Secondly exercise improves fitness and improves one's ability to tolerate cancer treatments including surgery, radiotherapy, and chemotherapy.
Finally, both the American Heart Association and the American Stroke Association have produced a "Presidential Advisory" notice for brain health entitled "Optimizing Brain Health". It includes physical activity as a key recommendation. The seven metrics for optimal brain health are as follows