Fitness facts to fuel your workout
By Melinda Wenner Moyer
There’s rarely enough time in the day to accomplish everything we set out to do, and exercise is often sacrificed when we’re short on time. Federal guidelines recommend fitting 2 1/2 hours of moderate physical activity into our lives each week — and making time for muscle-strengthening exercises.
I sometimes find this guidance daunting, and I’m not alone. Only 25% of adults in the United States met those recommendations in 2020. So I grew curious about the research: How much physical activity does a person need to live longer and reduce their risk of chronic disease? How frequently do they actually need to work out?
Exploring the science and talking to researchers generated surprising information, like you don’t need to work out every day, and stretching doesn’t automatically prevent injuries.
Here are research-based insights that might make you more excited to work out.
You can keep workouts short
The U.S. Department of Health and Human Services recommends that adults get at least 150 minutes of moderate exercise each week from activities like biking or swimming. That corresponds to just over 20 minutes a day. Still, you can benefit from doing less, said Dr. I-Min Lee, a public health researcher who studies exercise at Brigham and Women’s Hospital in Boston.
The first 20 minutes of physical activity per session confer the most health perks, at least in terms of longevity, Lee said. As you continue working out, “the bang for your buck starts to decrease” in terms of tangible health rewards, she added.
A study published in March estimated that 111,000 lives could be saved each year if Americans over 40 added just 10 minutes per day to their current exercise regimen.
But what if you only have five or 10 minutes to work out? Do it. “A lot of things happen in your body from the second you start to exercise,” said Carol Ewing Garber, a movement scientist at Columbia University Teachers College. And it’s possible to experience mental health benefits, including reduced anxiety and better sleep, right after a moderate-to-intense physical activity.
No need for intensity
If high-intensity interval training and hard-core spin classes make you want to hide, don’t worry. You don’t have to sweat profusely or feel wrecked after a workout to reap some rewards.
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% 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, said Beth Lewis, a sport and exercise physiologist at the University of Minnesota.
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,” Garber said. “That’s a really important message.”
Focus on 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 it has a larger effect on life expectancy than body type. Regardless of your size, exercise reduces your risk of heart disease, some kinds of cancer, depression, Type 2 diabetes, anxiety and insomnia, Lewis said.
Weekend-only routines are fine
I’ve always assumed that the healthiest exercisers work out almost every day, but research suggests otherwise. In a study published last month, 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 bouts. Other studies by Lee and her colleagues have drawn similar conclusions.
When it comes to possibly living longer, “it’s actually the total amount of activity per week that’s important,” Lee said. But, she added, if you work out more often, you’re less likely to get injured.
Stretching is optional
Recommendations to stretch before and after workouts annoy me, especially if I’m pressed for time. But research suggests that stretching doesn’t actually reduce your risk of injury. “It used to be a required part of what you do — ‘If you don’t stretch, you’re going to get hurt,’” Lewis said. “That mentality is wrong.”
Instead of static stretching — doing things like touching your toes — Lewis recommends doing dynamic stretches before you exercise, such as gently swinging each leg forward and back while standing. Static stretching can, however, help increase muscle flexibility and joint mobility, she explained. But now I know not to worry if I don’t have time to do it.