It is a well-proven fact that exercise is good for both your body and mind. Numerous studies over the years have shown that exercise is effective in preventing all kinds of diseases from heart disease to diabetes, cancer and osteoporosis. Simply by increasing your level of physical activity to about 15 minutes of jogging, cycling or swimming, or 30 minutes of walking a day - is associated with cutting your risk of premature death by about 20 percent.
A misconception about exercise is that you have to put in a lot of effort to get any noticeable benefit. However, simple activities such as walking have equally as good effects as vigorous exercise. Recent studies have found that in patients with type-2 diabetes, walking daily improved their blood fat levels, which reduces the risk of heart disease.  Other research found that more than 10,000 cases of breast and bowel cancer could be prevented each year by increasing physical activity such as going for brisk walks or performing vigorous household chores.
Exercise for Better mental health
There is also a huge body of evidence showing that exercise is vital for a healthy state of mind. For example, a study involving 10,000 participants found that those engaged in regular physical activity had much lower levels of anxiety, stress or depression. There was also a direct association between the amount of time spent in from of the TV or computer and poor mental health. 
Exercise literally prevents the physical deterioration of the brain. Our brains become less dense and lose volume as we age, and with that comes mental decline. Researchers used MRI scans to examine the brains of 55 elderly people. Those who exercised more and were more physically fit had the densest brains. 
Exercise for weight Control
One of the main benefits of exercise is that it increases your metabolic rate which means that you will use up more calories. Muscle cells use up more calories than fat cells, which helps with weight loss.
Exercise for Stronger bones
Exercise is great for the bones and joints. Stressing the bones with weight-bearing exercise, such as walking or weight-lifting, tells the bones to 'toughen up'. Clinical trials have shown that exercise is needed in addition to a good diet for bone health. Even gentle exercise has been found to prevent loss of bone mineral density , and the younger you are when you start exercising, the more positively it affects bone density and strength in later life. 
Exercise to Increase lifespan
According to research, regular exercise keeps signs of aging away and can prolong lifespan. However, the exercise must continue late into life and be sustained enough to raise the heart rate. It is thought that keeping the body fit helps fight the signs of aging by naturally stimulating the release of human growth hormone (HGH), which is key for strength, health, and longevity.
As you reach your 30s, you enter a phase called somatopause, in which HGH levels start decreasing dramatically. This is partly what drives the aging process. If you lead a sedentary lifestyle and don't exercise, your HGH levels will drop even further.
Given all these health benefits, who wouldn't want to exercise? Even 15 minutes a day can make a big difference to how you feel. Exercise immediately gives you more energy and mental clarity, making you more efficient and effective throughout the day. It is one of the key ways to optimize your overall health, from losing weight and gaining muscle, to improving your posture and physique, to living a longer healthier life, inshaa'Allah.
Which Exercises Are Best
The main categories of exercise are aerobic, resistance training and 'core' exercises, which stretch and tone the muscles. For peak fitness, a combination of all of these should be incorporated into your exercise regime.
Good forms of aerobic exercise are cycling, walking and jogging, which are beneficial for cardiovascular health. These should be combined with stretching and toning exercises, and strength training, which help to develop muscle strength and mass, and keep the body supple. Swimming is an excellent all-round exercise, and workouts like yoga and Pilates help to strengthen and tone 'core' muscles like the back, and maintain suppleness.
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-  Khan K, et al. Does childhood adolescence provide a unique opportunity for exercise to strengthen the skeleton? Journal of Science and medicine in Sport, 2000 Jun;3(2):150-64.