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QUICK ANSWERS

Is 20 minutes of HIIT enough?

Short sessions work, if they’re hard enough and you do them regularly

What the research found

Key study

Ten minutes, three times a week

  • Randomized trial
  • Inactive men
  • 12 weeks

A 10-minute session with three 20-second all-out sprints improved VO2peak, insulin sensitivity and muscle mitochondria as much as 50 minutes of moderate cycling, three times a week.

Source 2

Meta-analyses agree that HIIT improves fitness more than steady cardio 3, and reduces body fat about as much, in less time 4.

A 20-minute session

One way to fill 20 minutes.
PartTime
Warm-up, building up5 min
40/20 × 12 rounds12 min
Cool down3 min

What 20 minutes won’t cover

The guidelines also recommend muscle-strengthening activity on 2 or more days a week 1, which intervals alone don’t replace. Add two short strength sessions, or build bodyweight strength moves into your circuits.

Sources

  1. Bull FC, Al-Ansari SS, Biddle S, et al. World Health Organization 2020 guidelines on physical activity and sedentary behaviour. Br J Sports Med. 2020;54(24):1451-1462. doi.org/10.1136/bjsports-2020-102955
  2. Gillen JB, Martin BJ, MacInnis MJ, et al. Twelve Weeks of Sprint Interval Training Improves Indices of Cardiometabolic Health Similar to Traditional Endurance Training despite a Five-Fold Lower Exercise Volume and Time Commitment. PLoS One. 2016;11(4):e0154075. doi.org/10.1371/journal.pone.0154075
  3. Milanović Z, Sporiš G, Weston M. Effectiveness of High-Intensity Interval Training (HIT) and Continuous Endurance Training for VO2max Improvements: A Systematic Review and Meta-Analysis of Controlled Trials. Sports Med. 2015;45(10):1469-1481. doi.org/10.1007/s40279-015-0365-0
  4. Wewege M, van den Berg R, Ward RE, Keech A. The effects of high-intensity interval training vs. moderate-intensity continuous training on body composition in overweight and obese adults: a systematic review and meta-analysis. Obes Rev. 2017;18(6):635-646. doi.org/10.1111/obr.12532

YOUR NEXT SESSION STARTS HERE

Bring the effort.
We’ll keep the time.

Cero is free to download for iPhone, iPad and Apple Watch.

Download Cero
Cero’s simple timer on iPhone 18 Pro, with the green wave about half full during a high-intensity interval

Cero is a timer, not a medical device. If you’re new to hard exercise, are pregnant or have a health condition, check with your doctor first, and stop if you feel unwell.