40/20 Intervals: How the Format Works, With a Sample Session

Last updated October 21, 2026

The 40/20 interval structure is a popular intermediate format that challenges your stamina without requiring absolute maximum effort. Because you work twice as long as you rest, the fatigue builds steadily over the course of the session.

This routine features a series of high-impact and moderate-impact bodyweight moves. With only twenty seconds to recover between each forty-second push, you will need to manage your breathing and find a rhythm you can maintain from the first round to the last.

Format data

Work to rest: 2:1
Rounds: 12
Total time: about 17 minutes including warm-up
Level: Intermediate

The timeline

Block	Duration	Effort
Warm-up	5 min 00 s	easy to moderate
Work	0 min 40 s	hard
Rest	0 min 20 s	easy or still

Longer work with short rest; a common circuit format that is usually done at a hard but sustainable pace rather than all-out.

How it works

You will start with a five-minute easy warm-up to prepare your muscles and joints. Once you are ready, you will move into the main circuit, performing forty seconds of work followed immediately by twenty seconds of rest. You will complete twelve rounds in total, cycling through the six exercises twice. The entire session takes approximately seventeen minutes. This two-to-one work-to-rest ratio keeps you moving most of the time, so keep an eye on the clock to ensure your transitions are sharp.

How hard should it feel?

Since the work periods are long, do not sprint all-out. Aim for a hard but sustainable pace, landing around an RPE of seven or eight out of ten. You should be breathing heavily enough that speaking more than a few words at a time is difficult, but you should not feel completely exhausted until the final few rounds.

A sample session

Burpee: Pace yourself carefully here, as forty seconds of this full-body move will quickly spike your breathing.
Jump Squat: Focus on a soft landing and a steady rhythm rather than trying to jump as high as possible.
Mountain Climber: Keep your hips level and drive your knees forward at a brisk, even tempo.
Skater Jump: Use your arms for balance and push side to side with control to protect your knees.
Plank Jack: Maintain a tight core and avoid letting your lower back sag as your shoulders start to tire.
High Knees: Pump your arms and stay light on your toes to finish the circuit strong before the next round begins.

Who it suits

Intermediate trainees looking to build endurance with a challenging work-to-rest ratio.
People who prefer a steady, hard pace over maximum-effort sprinting.
Beginners or those with joint issues should pick a gentler format due to the high-impact exercises and short rest periods.

Common mistakes

Starting too fast. If you treat the first forty seconds like a sprint, you will struggle to finish the remaining rounds.
Skipping the warm-up. Take the full five minutes to loosen up, as jumping straight into high-impact moves increases your risk of injury.
Sloppy transitions. Use the twenty seconds of rest to get into position for the next move so you do not waste work time.

How to progress

Increase the total number of rounds to extend the workout duration.
Perform more repetitions of each exercise within the forty-second work blocks while maintaining good form.

Other formats

When to stop and see a doctor

Sharp or sudden pain in your knees, ankles, or lower back.
Dizziness, severe lightheadedness, or feeling faint during the short rest periods.
Chest pressure, tightness, or pain that radiates to your arm or jaw.

This page is general information, not medical advice. If you have a heart condition, high blood pressure, joint problems, are pregnant or have been inactive for a long time, talk to your doctor before starting vigorous exercise.

How this page was made. Timelines were set by our editors from common interval formats; times are a guide and you can scale them. Text drafted with AI assistance and checked by the Training Desk; see how we write. Last checked October 2026.