Working out three times a week

Why three days works

The Physical Activity Guidelines for Americans ask adults for muscle-strengthening activities that work all the major muscle groups on two or more days a week, plus 150 to 300 minutes of moderate aerobic activity, or 75 to 150 of vigorous activity. The NHS sets the same bar in the UK: strength work on at least two days, and 150 minutes of moderate or 75 of vigorous activity a week. In CDC data, only about 1 in 4 US adults (24.2% in 2020) met both the aerobic and the strength guidelines.

Three full-body sessions give you a margin: if life gets in the way and you miss one, you still train twice. Research on muscle growth backs the idea of training each muscle at least twice a week. A 2016 meta-analysis found that training each muscle group twice a week beat once a week; a larger 2019 analysis added that, for the same total number of sets, how often you train makes little difference. Spreading your sets over three shorter sessions is simply an easy way to fit the work in.

What one session looks like

Pick one exercise for each basic movement, so every session covers the legs, hips, back, abdomen, chest, shoulders and arms, the major muscle groups the NHS lists. Warm up with a couple of lighter sets of your first exercise, then work through the list:

• A squat, or a leg press on a machine.
• A hip hinge, such as a deadlift or a hip bridge.
• A push: push-ups, or a chest or shoulder press.
• A pull: rows or pull-downs.
• A core exercise, such as a plank.

How hard, and how many sets

The US guidelines give a simple test: each set should go to the point where it would be difficult to do another repetition. For strength, one set of 8 to 12 repetitions of each exercise is effective, although two or three sets may be more effective.

The weight doesn’t have to be heavy for your muscles to grow. A 2017 meta-analysis found similar muscle gains with light and heavy loads when sets were taken to failure, while heavier loads built more maximal strength. If your one-rep max matters to you, include some heavier sets; the one-rep max calculator estimates it from a set of 2 to 10 reps, so you never have to test a true max.

How to keep improving

In the words of the US guidelines, strength grows through gradual increases in the amount of weight, the number of sets or repetitions, or the number of days a week. A practical way to do it: when you can do 12 clean reps on every set of an exercise, add a little weight and drop back to 8.

If you’re starting from nothing, start low and go slow, as the guidelines put it. They suggest beginning with just one day a week of strength work at a light or moderate effort, then building up to two days and possibly more. Starting with one or two sessions and growing into three is a perfectly good plan.

Rest, cardio and safety

Rest days are part of the plan: Monday, Wednesday and Friday, or any three days with a day off in between. Sleep counts too; the CDC says adults aged 18 to 60 need 7 or more hours a night.

On the days in between, walking, cycling or swimming get you toward the 150 minutes of aerobic activity. If you have a chronic condition or symptoms, the guidelines say to be under the care of a health care provider, so check with your doctor before you start. Older adults should also add balance training, such as walking heel to toe or practicing standing up from a chair.