Here’s how much exercise you should get—and why it’s okay if you fall short | Popular Science
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Here’s how much exercise you should get—and why it’s okay if you fall short

New guidelines for Americans emphasize physical activity at any level.

a woman holding herself up over a metal bar

This person is strengthening muscles and bones at the same time!

If you’re one of the 80 percent of Americans who aren’t getting the doctor-recommended amount of exercise, you might be dreading the rest of this article. We’re about to spell out for you how much experts at the Department of Health and Human Services think you should be moving, which means statistically you’re pretty likely to find out you’re not clearing the bar. You might even click away in frustration. The HHS doesn’t know your life. It’s hard to find time to exercise.

And you know what? You’re right.

So this time around, the HHS decided to change tacks. Yes, they’re going to release information about exactly how much physical activity every American should get because that’s their job: to improve the health of our citizens. But for the same reason, they decided to emphasize something that's actually been embedded in the guidelines for the last decade. More physical activity is better, yes, but any activity is better than none.

Let’s get this over with: what are the guidelines?

The 2018 update to the national guidelines includes recommendations for everyone over the age of three, so we’re gonna break it down for you the same way the HHS does.

Preschoolers (age 3 to 5): Though they lack gym memberships, young kids still need plenty of physical movement. Ideally, they’d get three hours of some kind of activity every day. That sounds like a lot, but keep in mind that for kids this age, “exercise” is really stuff like jumping rope, playing tag, and fooling around with their friends in the pool. Recess time counts toward their daily three hours, and so does racing around outside after school.

Kids and Teens (age 6 to 17): As they get older, healthy kids require slightly more vigorous exercise. An hour each day is ideal, and they should get some mix of aerobic, muscle-strengthening, and bone-strengthening exercise. You probably have a good sense of what counts as aerobic—something that gets your heart rate up and keeps it there. But guess what? Household chores like mowing the lawn, raking leaves, or even cleaning the bathroom counts as moderate activity too. Muscle-strengthening exercises could be the stereotypical weight training, but you could also work with a resistance band or simply your body weight. Building your bones requires impact or resistance. Jumping rope is one example, but any sport where you have to rapidly change direction (think tennis or basketball) works too, as do running and weightlifting. Take your pick, just get some variety.

Adults (age 18 to 64): Here’s where the numbers get a little more complicated. The HHS says that in order to be healthy, adults should get a total of at least 150 minutes of moderate intensity exercise or at least 75 minutes of vigorous activity—plus muscle-strengthening exercises—at least two days per week. Moderate intensity would be things like a leisurely bike ride, doing light yard work, or simply a brisk walk. Vigorous would be more like hiking, running, or swimming laps. To train your muscles, lift something heavy. That could be your body weight, though as you get stronger you’ll eventually need to add resistance by using stretchy bands or actual weights you see in a gym.

Older Adults (65 and up): These are largely the same as those for younger adults: at least 150 minutes of moderate exercise or 75 of vigorous exercise a week. As we age, though, we become less able to do certain activities, either because of a chronic condition or because of plain old aging. The guidelines suggest simply that older adults continue to be as active as they’re able to be and that they engage in some kind of balance training. Think of those wobble boards at the gym, walking heel-toe, or even just practicing standing up from a sitting position. These activities can help older adults prevent falls, which can cause serious injuries that easily spiral out into long-term problems. Prevention is the key.

I don’t meet the guidelines: now what?

Good news: you, of all people, are going to get the most out of every single minute of activity you do. Seriously. Below is a graph we re-made based on data the HHS used, which is originally from a meta-analysis of many studies on the health benefits of physical activity.

It’s a little confusing at first because the x-axis seems to be saying that you need to get eight or nine hours of activity per week to meet the national guidelines. That’s because they’re measuring metabolic equivalents, or METs, which are both a measure of the time you’re exercising and the intensity with which you do it. Moderate activity, like a brisk walk, has a value of three METs—so if you walked for two hours each week you’d be getting six METs of exercise. There’s an MET multiplier value for almost everything, from lying in bed (one MET) to butchering animals (six), to roller-blading (12.5). You can check out a list here and find the value for whatever exercise you enjoy.

physical exercise benefits

Any amount of exercise is a good amount!

Infographic by Sara Chodosh

Getting the recommended amount of exercise gets you down to a hazard ratio of 0.68, meaning your risk of dying is 32 percent lower than someone who gets no exercise. But look how steep the first segment of that line is: Going from zero hours of exercise to anywhere between 0.1 and 3.74 METs of activity already drops your hazard ratio to 0.81. That means if all you do is go for a one-hour walk each week (or a 15-minute walk four times a week!) you’re getting a significant health benefit.

That’s even more reason to start out small. Almost no one goes from zero exercise to high-intensity interval training overnight and makes it stick. Try just walking briskly around the block when you get home from work each day, even if that’s only 10 minutes of activity. Do it for a week. Maybe next week you walk for 15 minutes, then 20. If you can make it to 30 minutes each day, guess what? You’re meeting the guideline for aerobic activity. And once you’re exercising for a half hour each day, it’ll be easier to start doing muscle training, like planks or push-ups or jumping rope. Soon you’ll be meeting the entire guideline! The key is simply to start small and work your way up slowly. What’s important is that you get there eventually instead of going too hard too fast and giving up.

Perhaps most important of all—and this is something that graph doesn’t show—is that you get all these benefits even if you don’t lose weight. Allow us to repeat that again, this time in the words of actual experts who wrote this HHS report: “The health benefits of physical activity are generally independent of body weight. The good news for people needing to lose weight is that regular physical activity provides major health benefits, no matter how their weight changes over time.” So please, do not get discouraged if you don't see changes when you step on the scale: you're doing your body a world of good.

I hate exercising: why should I do it?

Exercise is one of those things that somehow has even more benefits than you think. The HHS report summarizes the science on how physical activity helps us, and it reads more like a laundry list of all the body’s systems. It helps your brain, your muscles, your skeleton, your heart, your blood vessels, and your lungs. Getting exercise helps you sleep better. It helps you breathe better. It staves off all manner of diseases, from Alzheimer’s to diabetes. It prevents older people from falling, reduces anxiety and depression, and lowers your risk of all kinds of cancers.

So in short, the answer is that you should exercise because it will improve almost every aspect of your life. Hopefully, that’s reason enough. Who knows, you might find an activity that you come to love. But even if you don't, you can absolutely turn that dreaded trip to the gym into just another healthy habit.

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