Time magazine had a double issue for 9/12/16 and 9/19/16. The issue has an article about the science of exercise. Here are some interesting parts or claims.
There was a study done with 2 groups of genetically engineered mice. The mice were engineered to age prematurely. Some will set to exercise and some were not. Those who did not exercise got fat and sick. Those who exercised did not age very much and were lean and had no tumors.
They say that the statistics are that 20% of Americans get the 150 minutes of recommended physical activity, that more than half of baby boomers do no exercise whatever and that 80 million Americans over 6 are inactive.
Nearly half of high school students do not have weekly pe class and 15% or so of elementary schools expect only about 3 days a week of activity.
Exercise extends lifespan by about 5 years and slows down the aging of cells.
There is a sentence that says that exercise is not an effective way to lose weight. That is pretty dumb; it depends on how much and what kinds of exercise a person does!