The Physical Activity Guidelines for Americans (and similar recommendations from other countries) call for healthy adults to get 150 minutes of moderate exercise, like walking, per week. Vigorous exercise counts double, so if you’re a runner, you can meet the minimum guidelines with 75 minutes. But what if you have the time to do more—is that helpful to your health? And where does strength training fall?
The guidelines consider strength training to be separate from the guidelines exercise duration. (You should strength train twice a week in addition to getting in your minutes of aerobic exercise.) But a new study has looked at how many minutes of exercise are linked to lowered mortality, and it included strength training in its accounting.
According to the new findings, people who exercise four times as much as the minimum guidelines—that’s 600 minutes of moderate exercise, or 300 minutes of vigorous exercise—seem to be healthier than those who only meet the minimum (150/75). And exercising more than even that seems to be fine—people sometimes wonder if there is such a thing as “too much” exercise, but this study didn’t find such a number in their analysis. (Overtraining is a thing among high level athletes, but you’re not likely to trigger that with casual or recreational exercise.)
What does this mean for my exercise routine?
First of all, this isn’t a change in guidelines. I still think it’s good to try to meet the guidelines as a first step toward becoming healthier. As a weightlifter who spent several years doing zero cardio, I purposely added a daily walk (30 minutes per day × seven days per week = 210 minutes). While it’s too soon to say whether that’s extended my lifespan, I’ve definitely noticed some benefits. The guidelines call for 150 minutes of moderate exercise (or 75 vigorous, or a combination) and say that if you can meet that easily, you should try for 300 minutes moderate (150 vigorous).
Secondly, it’s important to know this was a study of the association between exercise time and mortality. When people are in poor health, they often have a reduced ability to exercise. If grandma’s health was declining in the years before she died and she couldn’t go on her daily walks anymore, it’s probably not the lack of walking that killed her.
But that doesn’t mean the numbers are useless. Health and exercise tend to build on each other. If you’re healthy to start with and you exercise more, that can help you stay healthy. Cardio benefits your heart health; strength training gives you more muscle mass, which can help you maintain your quality of life as you get older, and reduce your chances of complications from whatever health issues you do experience.
Besides providing encouragement to exercise more, if you have the time and ability, this study also gives us another way to ask ourselves if we are getting enough exercise to maintain our health:
You can ask if you’re meeting the 150+ minutes of aerobic exercise, plus two strength training sessions each week.
You can add up all your exercise (including strength training) and see where you fall on the range of 150 to 600 minutes.
What counts as exercise?
“Moderate” exercise, according to the physical activity guidelines, is anything between 3 and 6 METs, or metabolic equivalents. (One MET is the amount of energy you burn when doing absolutely nothing.) A few examples:
Walking at 2.5 miles per hour or more (the average person walks at about 3.0)
Mopping a floor, or sweeping with “moderate effort”
Cleaning the garage
Mowing the lawn
Leisurely bicycling (slow speed, on flat ground)
Golf
Horseback riding
Playing with your kid, where you’re walking and running around
The Physical Activity guidelines consider anything below 3 METs to be “light” rather than “moderate” activity. This includes most activities where you’re standing around or only moving a bit, like dusting furniture or grocery shopping. The recent study, which was self-reported, considered all activity below 6 METs to be in the moderate category.
Vigorous exercise, where the minutes count double, includes anything 6 METs or above:
Running at a 13-minute mile (4 mph) or faster
Dance aerobics classes
Hiking uphill or with a pack
Bicycling to get somewhere (10 mph or more, or uphill)
Roller skating
Swimming laps
Shoveling snow
Jumping rope
Most team sports (soccer, basketball, etc)
You can find the MET values for 800+ activities here. Butchering a large animal? Dancing the polka? Both vigorous intensity, in case you were wondering.