Any physical activity that gets your heart beating a little faster is useful. If you’ve never tracked your heartbeat while exercising, it might be worth trying. For moderate exercise, the recommended target is roughly 50 to 70 percent of your body’s maximum heart rate. (To calculate your maximum heart rate, subtract your age from 220.) Many people will hit this target during a brisk walk, Dr. Lewis said.
Estimating your maximum heart rate can help you gauge how hard you should be walking, running or cycling. But it’s not perfect, since your natural heart rate during exercise may be higher or lower. Plus, the fitness levels and heart rates among people the same age can vary, and not all exercises raise your heart rate the same amount. Consider talking to your doctor before establishing your goals.
“Just moving your body in some way is going to be helpful,” Dr. Garber said. “That’s a really important message.”
The focus is on overall health, not weight loss.
Many people exercise with weight loss in mind, but merely increasing physical activity usually isn’t effective. In a 2011 review of 14 published papers, scientists found that people with bigger bodies who did aerobic exercise for at least two hours a week lost an average of only 3.5 pounds over six months. And in a small 2018 clinical trial, women who did high-intensity circuit training three times a week didn’t see significant weight loss after eight weeks. (They did, however, gain muscle.)
Exercise improves your overall health, and studies suggest that it has a greater effect on life expectancy than body type. Regardless of your size, exercise reduces your risk of heart disease, some types of cancer, depression, type 2 diabetes, anxiety and insomnia, said Beth Lewis, a sport and exercise physiologist at the University of Minnesota.
It’s OK if you can only work out on weekends.
I’ve always assumed that the healthiest exercisers work out almost every day, but research suggests otherwise. In a study published in July, researchers followed more than 350,000 healthy American adults for an average of over 10 years. They found that people who exercised at least 150 minutes a week, over one or two days, were no more likely to die for any reason than those who reached 150 minutes in shorter, more frequent bouts. Other studies by Dr. Lee and her colleagues have drawn similar conclusions.