People have been trying to figure out forever what the right amount of exercise is, but the focus lately is on the shortest period possible.
In the past, formal recommendations have called for a substantial amount of regular exercise. For example, published guidelines from the Health and Human Services Department in 2008 suggested 150 minutes of moderate exercise per week — the equivalent of five 30-minute walks. The guidelines added that 75 minutes of vigorous exercise a week, like jogging, could be substituted.
These guidelines were based on a large body of science showing that 150 minutes of moderate exercise was associated with a longer life span and a reduced risk of heart disease, diabetes and other illnesses.