How much exercise is enough?

We’re used to hearing "Everyone should do half an hour of exercise, five times per week.”, but is this approach to fitness still relevant?

The ‘right’ amount of exercise

The advice probably sounds familiar: after all, official health organisations such the Australian and UK governments, World Health Organisation and American College of Sports Medicine advocate that a minimum of 30 minutes of aerobic physical activity, five days per week is a requirement for maintaining good health.

In most cases, for increased fitness, we’re advised to up our quota to 300 minutes per week, or 150 minutes at vigorous intensity.

The US government also recommends 60 or even 90-minute daily workouts for those who are overweight, acknowledging that more exercise might be needed for some to maintain a healthy weight. Essentially the message has been the more exercise, the better.

A quick HIIT

However, new research is coming to light that spending hours at the gym may not be the only approach. Instead, High Intensity Interval Training (HIIT) is becoming increasingly popular as a more modern attitude to exercise.

What it involves

HIIT involves repeatedly exercising at a high intensity for short bursts, separated by intervals of recovery (no or low-intensity exercise).

A typical workout might include a few minutes’ gentle cycling to warm up, followed by 20 seconds going flat out, then 10 seconds’ rest. This is repeated eight times, resulting in an intense but efficient workout lasting only four minutes.

So if you’re keen to get results, HIIT is an excellent way to maximise your workout when you’re short on time.

Does it really work?

HIIT has been shown to:

  • improve aerobic fitness and VO2 max – a measure of how good your heart and lungs are at getting
    oxygen into the body
  • improve insulin sensitivity, allowing effective management of blood sugar levels
  • significantly reduce body fat, especially abdominal fat
  • burn more calories post-exercise than steady-state exercise.

A study showed that two weeks of high-intensity intervals improved aerobic ability as much as six to eight weeks of endurance training.

What’s the verdict?

HIIT won’t suit everyone because although it’s short, it’s intense. Those 20 seconds can feel like the longest of your life!

There’s also not much evidence to suggest HIIT will develop the muscular endurance needed for longer training sessions.

Then there’s the issue of mental stamina: if you get used to four-minute workouts, will you still have the persistence needed to take on longer physical challenges?

Nonetheless, the benefits of HIIT are clear, so why not consider supplementing your exercise regime with a few bursts of HIIT?

As with all new exercise regimes, if you have a pre-existing medical condition you should consult your doctor before trying it out.

A study showed that two weeks of high-intensity intervals improved aerobic ability as much as six to eight weeks of endurance training.

What’s the verdict?

HIIT won’t suit everyone because although it’s short, it’s intense. Those 20 seconds can feel like the longest of your life!

There’s also not much evidence to suggest HIIT will develop the muscular endurance needed for longer training sessions.

Then there’s the issue of mental stamina: if you get used to four-minute workouts, will you still have the persistence needed to take on longer physical challenges?

Nonetheless, the benefits of HIIT are clear, so why not consider supplementing your exercise regime with a few bursts of HIIT?

As with all new exercise regimes, if you have a pre-existing medical condition you should consult your doctor before trying it out.

References: health.gov.au/internet/main/publishing.nsf/Content/health-pubhlth-strateg-phys-actguidelines#guidelines_adults; who.int/dietphysicalactivity/factsheet_adults/en/index.html; acsm.org/about-acsm/media-room/news-releases/2011/08/01/acsm-issues-newrecommendations-on-quantity-and-quality-of-exercise; gov.uk/government/publications/uk-physical-activity-guidelines;
webmd.com/fitness-exercise/guide/your-exercise-routinehow-much-is-enough; shape.com/fitness/workouts/8-benefits-high-intensity-interval-training-hiit

Information provided in this article is not medical advice and you should consult with your healthcare practitioner. Australian Unity accepts no responsibility for the accuracy of any of the opinions, advice, representations or information contained in this publication. Readers should rely on their own advice and enquiries in making decisions affecting their own health, wellbeing or interest.