Just 1 minute of intense exercise produces health benefits similar to 50 minutes of moderate exercise

No time to exercise? Now you have no excuse.
April 27, 2016

Intense trumps moderate (credit: iStock)

Researchers at McMaster University have found that a single minute of very intense exercise within a 10-minute session produces health benefits similar to those from 50 minutes of moderate-intensity continuous exercise.

Brief bursts of intense exercise are remarkably effective, a very time-efficient workout strategy, according to Martin Gibala, a professor of kinesiology at McMaster and lead author on the study, published online in an open-access paper in the journal PLOS ONE

Gibala and associates compared their “sprint interval training” (SIT) protocol to moderate-intensity continuous training (MICT), which is recommended in current public-health guidelines. They examined key health indicators, including insulin sensitivity (a measure of how the body regulates blood sugar) and cardiorespiratory fitness.

Quick intense vs. longer moderate

The ”sprint interval training” (SIT) protocol in the experiment involved three intermittent 20-second “all-out” cycle sprints interspersed with two minutes of continuous low-intensity exercise for recovery. MICT (the current exercise guideline) involves 45 minutes of continuous cycling at ~70% maximal heart rate. Both protocols involve a two-minute warm-up and three-minute cool-down.

In the experiment, a total of 27 sedentary men were recruited and assigned to perform three weekly sessions of either intense or moderate training for 12 weeks, or to a control group that did not exercise.

After 12 weeks of training, the results were remarkably similar, even though the MICT protocol involved five times as much exercise and a five-fold greater time commitment. Specifically, the researchers found a strikingly similar 19% improvement in cardiorespiratory fitness as determined by peak oxygen uptake (VO2 peak), which compares favorably with the typical change reported after several months of traditional endurance training (MICT).

“Most people cite ‘lack of time’ as the main reason for not being active,” says Gibala. “Our study shows that an interval-based approach can be more efficient — you can get health and fitness benefits comparable to the traditional approach, in less time. The basic principles apply to many forms of exercise. Climbing a few flights of stairs on your lunch hour can provide a quick and effective workout. The health benefits are significant.”

This project was supported by an operating grant from the Natural Sciences and Engineering Research Council, and an internally-sponsored research grant from McMaster University to MJG.

McMaster | Gibala on HIIT

Abstract of 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

Aims: We investigated whether sprint interval training (SIT) was a time-efficient exercise strategy to improve insulin sensitivity and other indices of cardiometabolic health to the same extent as traditional moderate-intensity continuous training (MICT). SIT involved 1 minute of intense exercise within a 10-minute time commitment, whereas MICT involved 50 minutes of continuous exercise per session.

Methods: Sedentary men (27±8y; BMI = 26±6kg/m2) performed three weekly sessions of SIT (n = 9) or MICT (n = 10) for 12 weeks or served as non-training controls (n = 6). SIT involved 3×20-second ‘all-out’ cycle sprints (~500W) interspersed with 2 minutes of cycling at 50W, whereas MICT involved 45 minutes of continuous cycling at ~70% maximal heart rate (~110W). Both protocols involved a 2-minute warm-up and 3-minute cool-down at 50W.

Results: Peak oxygen uptake increased after training by 19% in both groups (SIT: 32±7 to 38±8; MICT: 34±6 to 40±8ml/kg/min; p<0.001 for both). Insulin sensitivity index (CSI), determined by intravenous glucose tolerance tests performed before and 72 hours after training, increased similarly after SIT (4.9±2.5 to 7.5±4.7, p = 0.002) and MICT (5.0±3.3 to 6.7±5.0 x 10−4 min-1[μU/mL]-1, p = 0.013) (p<0.05). Skeletal muscle mitochondrial content also increased similarly after SIT and MICT, as primarily reflected by the maximal activity of citrate synthase (CS; P<0.001). The corresponding changes in the control group were small for VO2peak (p = 0.99), CSI (p = 0.63) and CS (p = 0.97).

Conclusions: Twelve weeks of brief intense interval exercise improved indices of cardiometabolic health to the same extent as traditional endurance training in sedentary men, despite a five-fold lower exercise volume and time commitment.