High-intensity interval training improves insulin sensitivity


As of September 2017, new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Check out my bestselling new book on the science of endurance, ENDURE: Mind, Body, and the Curiously Elastic Limits of Human Performance, published in February 2018 with a foreword by Malcolm Gladwell.

- Alex Hutchinson (@sweatscience)


“High-intensity interval training” (HIT) has been a big buzzword for the past few years, with plenty of studies showing that short, intense bursts of exercise can produce many of the same results as long, steady cardio sessions. Martin Gibala’s group at McMaster just published a new study in Medicine & Science in Sports & Exercise with a couple of points worth noting:

  • You don’t have go “all out”: Many of the early studies used 30-second Wingate tests at 100% exertion, which is pretty challenging for inexperienced or unfit exercisers. The more moderate protocol Gibala has been studying is cycling 10 x 60s hard with 60s recovery. The hard sections were done at 60% peak power (80-95% of heart rate reserve) — so hard, but not fall-off-the-bike hard.
  • Anyone can do it: Instead of using relatively fit subjects, this study used older (average age 45) subjects who were sedentary (no regular exercise program for at least a year).

The most interesting result for me: subjects improved their insulin sensitivity by 35% on average after just two weeks, three sessions a week. Lots of other parameters also improved, but insulin sensitivity is something that we know is crucially important in avoiding and managing metabolic syndrome. And the whole workout, including the three-minute warm-up and five-minute warm-down, takes less than half an hour.

By no means am I suggesting that interval training is the One True Answer to fitness (and neither are Gibala et al.). There are good arguments for varying what type of workout you do. But in terms of bang for buck, it’s hard to compete with HIT.

5 Replies to “High-intensity interval training improves insulin sensitivity”

  1. I’m glad to hear about this new research. With 79 million U.S. adults having prediabetes – that’s one in three – HIIT may well play a role in preventing conversion to diabetes.

    I hope your book is still on track for May publication. I’d like to see it.


  2. What does Constant-load, low-volume HIT mean? I am 48, overweight, sedentary, and just diagnosed with diabetes. Doing some research on improving insulin sensitivity.

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