Even very vigorous exercise—like the interval workouts Gibala is studying—can, in fact, be appropriate for people with different chronic conditions, from Type 2 diabetes to heart failure. That’s new thinking, because for decades, people with certain diseases were advised not to exercise. Now scientists know that far more people can and should exercise. A recent analysis of more than 300 clinical trials discovered that for people recovering from a stroke, exercise was even more effective at helping them rehabilitate.
“Inactivity is associated with increased risk for a number of cancers, including colon and breast cancer,” McCleary says. “Exercise has been linked with a decreased risk of developing cancer, death from cancer, and recurrence of certain cancers.” The suggested mechanisms at play include exercise’s beneficial effects on the immune and surveillance systems that detect and kill cancer cells, improved cardio-respiratory status, improved hormonal profiles, weight maintenance, and other beneficial metabolic effects, he says.
The body uses both carbohydrates and fats as energy sources. But after consistent aerobic exercise training, the body gets better at burning fat, which requires a lot of oxygen to convert it into energy. “One of the benefits of exercise training is that our cardiovascular system gets stronger and better at delivering oxygen, so we are able to metabolize more fat as an energy source,” Hackney says. As a result, your fat cells—which produce the substances responsible for chronic low-grade inflammation—shrink, and so does inflammation.
You can choose to do them on your knees or on your toes, as well as a wide variety of push up variations to target specific muscle groups in the arm. Place your arms closer to your body or farther out to lose fat in a specific area. If you’re really serious about losing arm fat, drop down and do a set of push ups whenever you have time. In the office, on lunch or while you’re catching up on the news, a set here and there can help you get rid of arm fat and transform arm muscles.

A workout once in a blue moon won’t do it, she says: you really have to exercise regularly, since hormone levels largely return to baseline after you exercise. That said, there’s an effect that accrues over time, which is what you want to harness by being active at least a few times a week. “What I’d caution readers is not to view our results as ‘one 20-minute moderate exercise will be a cure for all inflammatory conditions,’” says Hong. “These significant immune effects we observed occurred immediately with one bout of exercise, and likely will occur each time one exercises. So every time you exercise you’d see this effect, which will be cumulative over time.”
“Being active as we age can play a role in cognitive function, and reduce the risk of disease such as dementia and Alzheimer's,” says Amanda Paluch, a postdoctoral researcher at the Northwestern University Feinberg School of Medicine. “Research has explored several mechanisms, finding that exercise can increase synaptic plasticity and strength of nerve impulses in the brain, and have a positive effect on the hippocampus.”
Exercise helps people to lose and maintain weight. An exercise session burns calories and elevates metabolic rate both during exercise and then for hours after exercise is completed. It helps to preserve and build lean muscle mass. It works to suppress appetite. All of these benefits work together to make exercise vital for maintaining weight loss.
Exercise stretches muscles and joints, which in turn can increase flexibility and help prevent injuries. Exercise may also improve balance by increasing strength of the tissues around joints and throughout the body, thus helping to prevent falls. Weight-bearing exercise, such as brisk walking and weight training, strengthens bones and helps prevent osteoporosis. Exercise often can improve function and reduce pain in people with osteoarthritis, although regimens must be developed specifically for each person, and exercises that put undue strain on joints, such as jumping and running, may need to be avoided.

Endorphins, amiright? The link between exercise and happiness has been well-studied, and the results are very positive (just like you’ll be after some gym time). One study from the University of Vermont found that just 20 minutes of exercise can boost your mood for 12 hours. Cardio and strength training can both give you a lift, and 30-60 minutes of exercise three to five days a week is optimal for mood benefits, according to the U.S. Office of Disease Prevention and Health Promotion.