You may want to consider clocking even more minutes: Evidence directly linking exercise with cancer prevention is not yet conclusive, but the recent study mentioned above found that for previously inactive postmenopausal women, adding 300 minutes of moderate or vigorous aerobic exercise each week was more beneficial in reducing body fat—which is known to increase breast cancer risk—compared with 150 minutes of exercise per week.
Study author Christine Friedenreich, PhD, scientific leader of cancer epidemiology and prevention research at Alberta Health Services, says the bottom line is that more exercise could lower breast cancer risk even more than previous research suggested: "We know that doing 150 minutes per week is beneficial, but 300 is better."
If you want to sleep better...
Research consistently shows that exercise plays an important role in catching those ZZZs and waking up feeling rested. One study of more than 2,600 adults found that those who clocked at least 150/75 minutes of moderate/vigorous physical activity each week reported a 65 percent improvement in overall sleep quality, were 68 percent less likely to report having leg cramps during the night, and were 45 percent less likely to report having difficulty concentrating when they felt tired, compared to those in the study who had not met those physical activity benchmarks.
Watch the timing of your workouts, however.
"Some people do very well exercising in the evening, but others find doing it within a few hours of bedtime has an adverse effect on their ability to fall asleep or stay asleep," Cadmus-Bertram notes.
If the latter is the case for you, plan to work out first thing in the morning or before lunch.
If you tend to sit for most of your day...
In addition to the 150/75-minute prescription, try to move about every hour for a couple of minutes. Studies have linked higher sedentary behavior with higher rates of cardiovascular disease, cancer incidence, type 2 diabetes, and death from any cause, according to a report in the Annals of Internal Medicine—and that holds true even for people who meet the activity guidelines!
"We all know our bodies did not evolve to sit in chairs all day," says Cadmus-Bertram.
More From Prevention: The No Squat Belly, Butt, And Thighs Workout
The good news is that a recent study found 2 minutes of walking every hour could help reverse the negative effects of sitting. The researchers found that 2 minutes each hour of even light intensity activity (such as walking) equaled a 33 percent lower risk of death for the 3,242 adults in the study. You can make it part of your routine by setting a reminder on your computer or phone to take breaks every hour—or use an app, like Stand Up! (for iPhone or iPad) or BreakTaker (for Windows).
So remember: The bare minimum amount of activity to stay healthy and sleep well is 150/75 minutes of moderate/vigorous activity a week; double that amount if your goal is to lose weight. And if that seems overwhelming, remember that you can break up your workouts—every little bit of activity helps, and doing something is always better than nothing.