The Old Science: "Walking Is Enough" Let's frame the health
question with some data from the American Heart Association: A
sedentary lifestyle is one of the 5 major risk factors (along
with high blood pressure, abnormal values for blood lipids,
smoking, and obesity) for cardiovascular disease. The American
Heart Association used to say (and the government agreed) that
virtually anything would satisfy the bare minimum for avoiding
that "sedentary lifestyle": [The benefits of exercise] will
generally occur by engaging in at least 30 minutes of modest
activity on most, preferably all, days of the week. Modest
activity is defined as any activity that is similar in intensity
to brisk walking at a rate of about 3 to 4 miles per hour. That
30 minutes was even considered cumulative across the day: It has
been shown that repeated intermittent or shorter bouts of
activity (such as 10 minutes) that include occupational and
recreational activity or the tasks of daily living have similar
cardiovascular and other health be