January 27, 2021

HIIT versus Moderate Exercise


A study, published in Medicine & Science in Sports & Exercise, finds health benefits in both short, intense, interval training and those of longer, moderate workouts.

Each approach to exercise has advantages, but the impacts on blood pressure, body fat and other aspects of metabolism may be greater after standard, half-hour, moderate workouts than high intensity interval training (HIIT).

Current United States and Australian exercise guidelines for each type of activity differ.

  • Interval train no more than three times a week, to avoid over-straining muscles, tendons, ligaments, joints and cardiovascular systems, meaning if we exercise only with HIIT, we are inactive four days a week or so.
  • Moderate exercise moving at least five times a week and for at least 30 minutes each time.

In the study, they recruited 23 sedentary, overweight, adult men. They measured their fitness, body compositions and blood pressures, and asked them to down shakes laden with big glops of fat to see how their metabolisms responded to the nutrient. They also fitted them with blood-sugar monitors to wear at home for a week to gauge their everyday blood-sugar control, a measure of metabolic health.

Half the men started interval training three times a week on stationary bicycles at the lab, riding hard  for 30 seconds, resting for two minutes, and repeating that sequence four to six times.

The other half began a moderate-exercise program, riding bikes at the lab five times a week at comfortable pace for 30 to 40 minutes.

Over the course of the next six weeks, the HIIT group pedaled intensely for a grand total of less than an hour, while the moderate-intensity group worked out for at least 2.5 hours each week for the same period.

At the end of the six weeks, both groups were re-tested.

  • The men almost all were fitter, and to about the same extent, however they exercised.
  • Men in the moderate-exercise group shed more body fat, improved their blood pressures or become better able to metabolize the extra fat from the unctuous shake.
  • Everyone’s blood-sugar control at home was best only on the days when they exercised, meaning three times a week for the HIIT riders and five for the moderate group. On the remaining days, blood sugar levels tended to rise.

Taken as a whole, the results indicate that intervals and traditional exercise alter our bodies in divergent ways, and we may want to consider what we hope to achieve with exercise when choosing how best to exercise, says Jamie Burr, a professor at the University of Guelph

Scheduling a 7 day period of a blend of light, moderate and high intensity is the most effective way to exercise develop and maintain results while minimising injury.

Periodising provides your body with varying loadings and intensities that allow your body’s muscles to develop, but also is self balancing your recovery and exercising consistently without injury.

Using running as an example:

  • Jogging is moderate,
  • Sprinting is high intensity
  • Walking and stretching is low intensity.

The three intensities combined, provide stimulus on the muscle at fast and slow twitch muscle stage, providing muscle and bone development, then low intensity to aid muscle recovery, and ligament, tendon and joint recovery.