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Pressed for Time? Try this Workout Shortcut
Quick, intense exercise may rival the cardio-respiratory results of a 45-minute workout 06/14/2016 By Craig Weatherby with Michelle Lee
Many Americans aren't as fit as they should be.

And many are hard pressed to find enough for time for exercise.

Conventional wisdom calls for 30 to 45 minutes of aerobic exercise daily.

But it can be challenging to find that much time … especially if you spend as much or more commuting.

What if you could get the heart and lung benefits of a moderate-pace, 45-minute aerobic workout in 10 minutes or less?

If that sounds too good to be true, read on.

Aerobic exercise brings heart-lung benefits
The chief goal of aerobic exercise is to boost cardio-respiratory fitness.

Cardio-respiratory fitness (CRF) is gauged by the capacity of these closely connected systems to supply oxygen to muscles during exercise.

Regular physical activity boosts cardio-respiratory capacity by enlarging the heart muscle – enabling more blood to be pumped – and expanding the number of small arteries in muscles.

CRF is essential to reducing the risk of heart disease, lung cancer, diabetes, stroke, and other diseases.

Interval training: More heart-lung benefits in less time
Interval training (IT) is a pretty straightforward concept.

Typical recommendations for aerobic exercise call for exercising at a moderate pace for 30 to 45 minutes.

(The most common types are jogging, running, swimming, cycling, treadmills, and elliptical machines.)

Instead of running or cycling at a steady, moderate pace, interval training alternates bursts of fairly intense exercise with periods of lighter exercise.

For example, you might alternate two minutes of brisk walking with one minute of fast sprinting, and continue that pattern for 20 to 30 minutes 

Interval training can deliver greater cardio-respiratory fitness gains than traditional, steady-pace aerobic exercise, and do it in less time. 

There's good evidence that interval training delivers special benefits:
  • Burn extra calories
  • Boost aerobic capacity
  • Sustain motivation by mixing up your workout
High-intensity interval training: Greatest benefits in least time
So-called "high-intensity interval training” or HIIT resembles regular interval training.

Like regular interval training, HIIT alternates periods of relatively relaxed exercise with bursts of greater exertion.

But – compared with traditional interval training – the periods of greater exertion in HIIT are extremely intense and very brief.

Emerging evidence suggests that very short HIIT sessions can deliver greater benefits than either lengthier periods of traditional interval training, or far longer sessions of continuous, moderate-pace aerobic exercise.  

Early studies indicated that very short HIIT sessions can enhance muscle conditioning and the body's ability to regulate blood sugar levels

And the conclusions of a 2013 evidence review expanded the apparent benefits of HIIT.

For that review, an Australian-Norwegian team compared the cardio-respiratory benefits of traditional, moderate-pace training vs. HIIT exercise.

The review's authors examined 10 exercise studies conducted among people who were obese, diabetic, or had chronic heart and metabolic diseases.

Compared with moderate, continuous exercise, their evidence review indicated that HIIT is significantly more effective at improving cardiorespiratory fitness.

Get fit with the one- to 10-minute workout
Exciting new findings counter the common complaint that there just isn't enough time to get in shape.

The report comes from Canada's McMaster University, and it affirms the special benefits of high-intensity interval training (HIIT).

In earlier research, the McMaster team found that sprint interval training (SIT) – three 20-second, all-out cycle sprints – boosted overall fitness.

Their latest study compared the interval protocol described below (see "The study's interval training regimen") with 45 minutes of moderate, continuous cycling.

Professor Martin Gibala and his team set out to determine how sprint interval training (SIT) compared to moderate-intensity continuous training (MICT). 

Specifically, they looked at two key health indicators: cardiorespiratory fitness (CRF) and insulin sensitivity, a measure of how the body regulates blood sugar.

Twenty-seven men with sedentary lifestyles were recruited and assigned to one of three groups for a 12-week trial:
  • Control group – no exercise
  • Moderate-intensity training, 3 times per week
  • High-intensity interval training, 3 times per week
After 12 weeks of training, both exercise groups experienced very similar results.

This was pretty impressive, since the moderate-exercise group performed five times as much exercise and spent five times as much time exercising.

Physical endurance levels increased by almost 20 percent in both exercise groups, and insulin resistance (blood sugar regulation) also improved significantly.

And microscopic analysis of the muscle tissue in both exercise groups showed improved energy production and oxygen use.

According to Professor Gibala, "Most people cite ‘lack of time' as the main reason for not being active. This is a very time-efficient workout strategy. Brief bursts of intense exercise are remarkably effective.”

"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,” he says. "Climbing a few flights of stairs on your lunch hour can provide a quick and effective workout. The health benefits are significant.”

The study's sprint-interval training regimen 
Are you interested in giving this interval program a try? 

The high-intensity sprint-interval workout totals just 10 minutes, with only one minute of high-intensity exercise.

Here's the 10-minute routine tested in the Canadian study, which was performed on a stationary bike:
  1. Warm-up: 2 minutes
  2. Pedal as hard as possible: 20 seconds
  3. Recover with a slow ride: 2 minutes
  4. Pedal as hard as possible: 20 seconds
  5. Recover with a slow ride: 2 minutes
  6. Pedal as hard as possible: 20 seconds
  7. Cool down: 3 minutes
Have you used interval training? We're curious to hear whether and how it's improved your well-being.

Send us a note, and let us know what works for you!

  • Gillen JB, Martin BJ, MacInnis MJ, Skelly LE, Tarnopolsky MA, Gibala MJ. 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. PLoS One. 2016 Apr 26;11(4):e0154075. doi: 10.1371/journal.pone.0154075. eCollection 2016. PubMed PMID: 27115137; PubMed Central PMCID: PMC4846072.
  • Weston KS, Wisløff U, Coombes JS. High-intensity interval training in patients with lifestyle-induced cardiometabolic disease: a systematic review and meta-analysis. Br J Sports Med. 2014;48: 1227–34. doi: 10.1136/bjsports-2013-092576. pmid:24144531