In the same week that we learned about the devastating metabolic effects of the weight loss induced by hours-long exhausting workouts in  participants in the “Biggest Loser”, a paper byJenna Gillen and colleagues from McMaster University, Hamilton, Canada, published in PLOS One, shows that all it takes is one minute of vigorous all out exercise to significantly improve your health.

Unbelievable as it sounds, the rather rigorous randomised controlled 12-week trial in 27 sedentary men showed just that.

The researchers divided the participants into three groups: three weekly sessions of sprint interval training (SIT) involving a total of 1 minute of intense exercise within a 10-minute time commitment (n = 9), three weekly sessions of traditional moderate-intensity continuous training (MICT) involving 50 minutes of continuous exercise per session (n = 10) or no 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{0d9774446e5c1c486b14bfd00f317fb53ff44ec6f4ca4ad04b1a0b82436e9f13} maximal heart rate (~110W). Both protocols involved a 2-minute warm-up and 3-minute cool-down at 50W.

Peak oxygen uptake increased by around 20{0d9774446e5c1c486b14bfd00f317fb53ff44ec6f4ca4ad04b1a0b82436e9f13} in both exercise groups as did insulin sensitivity as assessed by an intravenous glucose tolerance test.

Participants in both exercise groups also lost about 2{0d9774446e5c1c486b14bfd00f317fb53ff44ec6f4ca4ad04b1a0b82436e9f13} of body fat.

Furthermore, metabolic and mitochondrial function (as measured in muscle biopsies) improved similarly in both exercise groups.

Thus, the researchers conclude that

“12 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.”

This is not just news for people who find it hard to make the time for exercise (e.g. due to work or family commitments).

It is also of interest to anyone just trying to get fitter without wanting to invest hours in the gym.

The key however, is the term “all-out” – the 60 sec bout of exercise has to be at virtually maximum capacity, which may increase the risk of injury in some individuals and can hardly be described as “pleasant”.

As for the implications for my patients, who often present with considerable amount of excess weight and thus, every movement (e.g. just walking up a flight of stairs) often appears to happen at near maximum exercise capacity (no surprise given the tremendous weight that they are lifting and carrying), I can only speculate, of what these bouts of activity may have on their metabolic health.

Whatever the case, this study certainly corroborates the notion that one does not have to spend hours in the gym to improve one’s health.

@DrSharma
Vancouver, BC

(c) Dr. Sharma’s Obesity Notes – Read entire story here.