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The "Bare Minimum" Amount of Exercise You Need to Do to Be Fit, Says Study

A military-led study has established a new benchmark for maintaining your strength and endurance levels.

If you find exercise simply too much of a chore, you'll be interested in a new military-led study whose findings were recently published in the Journal of Strength & Conditioning Research, which sought to answer perhaps the single biggest question that those who prefer to live a more sedentary lifestyle have been asking for eons: "What is the bare minimum amount of exercise one needs to do to keep 'fit?'" Read on for the clear answer provided by the study. And for more news from the front lines of science, see why This Super-Quick Workout Is Scientifically Proven to Work, According to the Mayo Clinic.

This Is What It Means to Be "Fit"

Female athlete with protective face mask doing plank exercise with hand weights in a gym.

Finding a benchmark minimum for exercise is obviously relevant for those who serve in the military—and especially for the personnel who are deployed overseas and may find that they don't have as much time to log in the weight room. As such, the study was led by Barry Spiering, formerly Nike's research director, who oversaw a group of researchers at the United States Army Institute of Environmental Medicine. Ultimately, the researchers loosely define keeping fit as "preserving endurance and strength."

There are three main fitness components that the researchers highlighted: how often people should train, the volume of the training (distance, reps), and how intense those sessions are. The experts reviewed a series of previously conducted studies for answers.

For Your Endurance: Work Out Twice Per Week


"In general populations, endurance performance can be maintained for up to 15 weeks when training frequency is reduced to as little as 2 sessions per week or when exercise volume is reduced by 33-66% (as low as 13-26 minutes per session), as long as exercise intensity (exercising heart rate) is maintained," concludes the study.

So, if you like to run or swim for cardio, Spiering and team say that you only need to lace up your shoes—or put on your swimsuit—twice a week for less than half-an-hour at a time. Also, while you can bring down your frequency and your reps, you shouldn't shirk the intensity. If you're working out for 13 minutes, make it count.

For Your Muscles: Workout Once or Twice Per Week, Depending on Your Age

hiit workout

"Strength and muscle size (at least in younger populations) can be maintained for up to 32 weeks with as little as 1 session of strength training per week and 1 set per exercise, as long as exercise intensity (relative load) is maintained," concludes the study. "Whereas, in older populations, maintaining muscle size may require up to 2 sessions per week and 2-3 sets per exercise, while maintaining exercise intensity." And for more fitness news, see Why Everyone Is Going Crazy Over This Viral Walking Workout.

Again, Intensity Is Paramount

Woman running on treadmill

The researchers observed that one of the three aforementioned components was the most important when it comes to maintaining a bare minimum for fitness: exercise intensity. "Our primary conclusion is that exercise intensity seems to be the key variable for maintaining physical performance over time, despite relatively large reductions in exercise frequency and volume."

So if you're only hitting the gym one or twice a week for a small amount of time, you need to maximize that time by keeping the intensity of your workouts high.

What It All Means for You

arms up squat

Remember, the point of the study is not to see how much exercise people need to do to be fitter. Rather, it was to pinpoint exactly how much exercise is required to maintain a healthy state of endurance and strength. This is about finding a "bare minimum."

With this benchmark in mind, you can take steps to actually grow your strength and fitness levels, and improve your health. If you only need two days a week to maintain your endurance levels, you can grow from there. If time is an issue—and it always is—remember that there are plenty of reasons why high-intensity interval training (HIIT) is such a popular way to train and keep fit. Vigorous bursts of exercise test your muscles, your heart, and your lungs, and science has proven that—when contained to reasonable lengths—it totally works. But let's face it: The single biggest benefit to short bursts of training is arguably the fact that they're short bursts. Why camp out at the gym for hours when you can reap the benefits in 10 minutes or less? For further proof, see why This Workout Drives 29 Percent More Fat Loss, According to Science.

Read on for More Great Workouts from Eat This, Not That!

William Mayle
William Mayle is a UK-based writer who specializes in science, health, fitness, and other lifestyle topics. Read more about William
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