Good news for anyone who wants to work out and stay healthy, but has a crazy busy schedule (oh hey, majority of the world!): You don't need to exercise every. single. day. Or even a handful of days, for that matter.
Science says the intensity you put into your sweat is more important than how many times you actually break it.
A recent study published in the Journal of Strength and Conditioning Research found that those who worked out three days a week saw the same strength-building results as those who exercised six days a week. The participants performed bench presses, squats, and deadlifts, focusing on their one rep max (the max weight lifted for one repetition, a sign of strength).
While researchers controlled for volume and intensity—in this case, the total number of reps and sets for the week—both groups had similar strength and muscle-building results. (While only men participated in this study, researchers say the findings apply to women, too.)
The most important takeaway from the results? It's the total lifting volume, (i.e. total number of sets you complete) that matter the most, says study author, Bill Campbell, Ph.D., C.S.C.S., associate professor of exercise science and director of the Performance and Physique Enhancement Laboratory at the University of South Florida. "As long as the volume of your lifting program is sound, it doesn't matter if you do a lot in a fewer amount of days or if you do a little bit of lifting on many days of the week," says Campbell.
"If you're crunched for time overall and want to get stronger, you can get away with strength training one to two times a week to see gains," says Nike master trainer Joe Holder. "Just focus on hitting complex movements with decent weight." (Related: I Started Exercising Less and Now I'm Fitter Than Ever)
Measuring Volume and Intensity: The Crucial Fitness Factors
To get the biggest bang for the buck without wasting hours at the gym, you'll want to focus on volume and intensity.
Volume basically refers to the number of exercises you do, or the combined reps and sets. Intensity (obviously) means how hard you push it. If you're training to gain strength, Campbell says the ideal intensity is working to near failure. "You should stop [doing an exercise set] when you can only do one more repetition, or possibly two more reps, with perfect form," he explains. (Related: Should You Add Partial Reps to Your Training?)
If your goals go beyond strength and into muscle building or general health and fitness, you want to consider two types of fatigue. "One is mechanical fatigue or individual muscle fiber damage, where the mechanical stress will leave you a little sore the next day," says Pete McCall, C.S.C.S., San Diego-based trainer and All About Fitness podcast host.
"Then there's metabolic fatigue, which leads to muscle fatigue due to the depletion of glycogen. Muscles store glycogen and when you do really intense exercise, you get that burning sensation like you can't go any further—that means you use used the glycogen stores in your muscle," says McCall. You need about 24 to 48 hours to replenish that, he says. But it's a telltale sign you're working hard enough when you get that feeling of your legs on fire.
Regardless, if you're working this hard those rest days are going to be even more important. You can also opt for active recovery that lets your muscles replenish glycogen and your body get ready to dominate your next workout. (Related: This Is What the Ultimate Recovery Day Should Look Like)
The Importance of Rest Days
The reason three days a week might work well for your schedule is so you can fit in some quality rest and active recovery days. If you're doing HIIT workouts multiple days in a row, it could lead to some overuse issues or injuries. (Related: How I Learned to Love Rest Days)
"Too much HIIT causes overtraining, which causes injuries and negative effects," McCall cautions. "Recently, we've come across this over emphasis on HIIT, which actually causes people to step away from the gym. It's not designed to be done five to six days a week, rather just two or three." (Related: Here's Why You're So Hungry On Rest Days)
"Your body is in a stressful state post-workout—you've set off some sort of alarm reaction. For tough workouts you may need a little more time to return back to normal, therefore a rest day," says Holder. Typically, you want to schedule a rest day after a tough workout or a few moderately tough days in a row, he says. "This will allow you to increase circulation, push out cellular waste, and get the blood flow to the areas that need it." Active recovery days can include a casual walk, mini band work to get your glutes firing, foam rolling, or active stretching.
If you feel like you just need to get in a workout the day after a HIIT class, McCall says steady-state cardio is a good idea. "Go for a steady-state jog at 70-75 percent of your max effort. You're not overstressing tissues, you're not putting the same stressors on them and you're not pushing it," he explains. "You're probably going to be a bit sore during that first mile, but then it'll feel good and you will feel better after that moderate-intensity exercise. Movement helps your body recover, getting more oxygen to the tissues."
How to Make Your Workouts More Efficient
If you hop on the three-day-a-week train to get fit, there are a few things to keep in mind to make the most of your time spent sweating. First and foremost, all experts will tell you to go in with an idea of what you're tackling. Having a game plan for your strength, cardio, or HIIT session means no time wasted figuring out what to do. (Related: 8 Benefits of High-Intensity Interval Training)
For strength, Campbell suggests supersets. For example, this could mean alternating one set of triceps extensions and one set of bicep curls with one minute of rest between, rather than four sets of triceps, followed by four sets of biceps with two minutes of rests between each set. "This works great as you are taking advantage of the rest periods by allowing the muscle group to rest while working a different muscle group during that downtime," he says.
To improve general fitness, Holder suggests getting in three things: mobility work (i.e. dynamic stretching or band exercises), strength (likely weightlifting), and conditioning (such as a HIIT circuit). "Do something to improve strength, do something to improve your heart rate and energy systems, and do something that will improve the way you move," he says.
Workouts Should Hit the Ideal Intensity
Think of your weekly schedule of workouts in terms of rate of perceived exertion (how hard you feel you're working), says McCall. Spend some days at a nine to 10 RPE and then the other days at a five to seven. You should spend one day at about a two or three, which could even be your active recovery days. "The most strenuous part of this day is deciding if you should binge on Netflix or Amazon," he says. (Related: Here's What a Perfectly Balanced Week of Workouts Looks Like)
To maximize your workout time on those high-intensity days, trainers share their go-to plans:
Astrid Swan, a NASM-certified trainer, suggests five minutes of a dynamic warm-up, followed by banded exercises to activate the glutes (think clamshells, monster walks and standing left lifts). Then, she does a HIIT circuit featuring kettlebells or heavy dumbbells for goblet squats, deadlifts, burpees, renegade rows, and kettlebell swings.
Holder also recommends a five-minute warm-up, followed by five minutes of corrective exercises or mobility work (often using a band as well). Then, do 15 minutes of a total-body strength workout, featuring weighted complex movements (targeting a few muscle groups at once) mixed with conditioning intervals (sled pushes, sprints, etc.). Wrap that up with a five-minute cool-down (stretching or foam rolling will do).
Finally, McCall offers this plan: Four to five sets of 20 kettlebell swings, followed by two to four sets of 10 clean and jerks on each arm. Then, do pull-ups and push-ups to fatigue. (Want to get stronger with your push-ups? Check out the 30-day push-up challenge for seriously sculpted arms.) Finish with one or two Tabata bursts (20 seconds of all-out effort, followed by 10 seconds of total rest for eight rounds), on the assault bike or rower.
Your time just got freer, and your body, fitter.