Abundant research has shown benefits of exercise in preventing heart disease and cancer, as well as cognitive decline with age and even viral and bacterial infections. It has also been shown to be beneficial in recovering from heart attacks and in treating heart failure. Contrary to popular opinion, exercise is also beneficial in relieving pain and inflammation from arthritis.
Standards for fitness have been developed based on research. Basic fitness to prevent heart disease and cancer requires exertion to the point of mild shortness of breath and sweating, 30 minutes a day for five days a week. This is independent of the type of exercise.
A major goal in the modern era is to reduce obesity and Type II Diabetes, which are primarily caused by a more sedentary lifestyle. The requirement to actually reduce weight and to keep it off requires a full hour of mild shortness of breath and sweating, five days a week
In both cases, the days off are important for body recovery and prevention of injury.
Interestingly, the first 90% of health benefits occur in the first 10% of activity above sedentary levels. In other words just getting off the couch and going out for a vigorous hike or gardening or playing Frisbee has more benefit than rigorous training to high performance as a runner, swimmer, or soccer star. That increased training provides even more benefits, but the most significant decrease in health risk comes from that very first level of activity and exercise.
There is a movement in recent decades to exercise more, often identified with gym memberships and purchase of treadmills or ellipticals for home or hotel fitness rooms. These are better than nothing, but often this type of exercise is a rather grim discipline. Since sustaining the exercise is critical, the most important ingredient is enjoyment. All exercise is valuable, including dancing, hiking, gardening, swimming, house cleaning, as well as playing sports. People should do what they can enjoy for its own sake.
If there were to be one essential discipline, it would be to “suit up” five days a week. This means to put on the clothes you would wear for the exercise activity. Psychology is such that then you are most likely to proceed with the activity; indeed, if you have suited up and then discover you do not feel up to it, the best thing to do is to stop because your body is coming down with something or is not optimal in some way that might lead to injury. On the other hand, the worse eventuality would be to sit and read or watch TV while deciding not to work out today. That leads to a habit that prevents exercise.