The four-minute workout or aerobics is a waste of time

Dr. Izume Tabata is an exercise physiologist from Tokyo who has researched the effects of short, intense training on aerobic and cardiovascular fitness.

by Dr. Mark Force —

What if you could work out for just four minutes a day and receive more health benefits than you would from 60 minutes of daily aerobic exercise? You probably think I’m crazy! Well, I may be crazy, but I can prove the four-minute exercise regimen really works.

Dr. Izume Tabata is an exercise physiologist from Tokyo who has researched the effects of short, intense training on aerobic and cardiovascular fitness. Tabata’s first group of subjects were trained athletes who did interval training five consecutive days a week for six weeks. The workout structure consisted of eight maximum-effort intervals at approximately 170 percent of the subject’s peak oxygen uptake (VO2max) for 20 seconds, separated by 10-second rest periods. A second group did 60 minutes of exercise at 70 percent of peak oxygen uptake, five consecutive days a week.

VO2max is the maximum volume of oxygen the body can consume during intense, whole-body exercise, while breathing air at sea level. This volume is expressed as a rate, either liters per minute (l/min) or milliliters per kg of bodyweight per minute (ml/kg/min). Because oxygen consumption is linearly related to energy expenditure, when oxygen consumption is measured, we are indirectly measuring an individual’s maximal capacity to work aerobically.

At the end of the six-week study, Tabata found an average 28 percent increase in anaerobic capacity (amount of work a subject can perform before becoming anaerobic, or completely void of oxygen), along with a 14 percent increase in VO2max in the high-intensity interval training (HIT) group. In the moderate intensity group, there was a 10 percent increase in the VO2max and no increase in anaerobic capacity.

Results of the study showed that this interval workout structure “may tax both the anaerobic and aerobic energy releasing systems almost maximally.”

A later study by Tabata, using 30-second intervals with two-minute rest periods to exhaustion, found that his original improvements were not reproduced. The short rest intervals seem to be critical to the remarkable results found in the first study.

Kirsten Burgomaster and colleagues at McMaster University in Ontario, Canada, conducted a study with a variation of the high-intensity interval training. Participants in this study did four to seven “all-out” 30-second sprints on a bicycle ergometer with four-minute rest periods, for a total of six times over two weeks. The group showed a 38 percent increase in the ability to utilize oxygen and a 26 percent increase in muscle glycogen concentration.

There was no change in VO2max or anaerobic capacity; however, endurance capacity increased markedly. Average time to cycling fatigue increased from 26 minutes to 51 minutes while cycling at or near 80 percent of VO2max.

An extremely important result was the increased levels of the enzyme citrate synthase, which should correspond with improved insulin sensitivity and metabolism of fats, including burning of fats as energy and improved lipid profiles (lower triglycerides, LDLs and total cholesterol).

In another study, Tabata examined the effect of exercise on fatty acid oxidation (FAO) enzyme levels (fatty acid oxidation enzymes control the production of energy from fat burning in body cells). In one group, lab rats swam 14 intervals of 20 seconds, with 10 seconds of rest between them. The other group of lab rats swam six hours a day in two three-hour sessions, separated by 45 minutes of rest. FAO enzymes showed a 12 percent higher increase in the high-intensity group than in the moderate-intensity, prolonged duration group. The results of this study indicate that seven minutes of high-intensity exercise is more effective at increasing fat burning than six hours a day of moderate intensity exercise.

Although citrate synthase was not measured in Tabata’s swimming study, there is essentially a direct relationship between FAO enzyme and citrate synthase levels. Since FAO enzyme levels increased more with short-rest intervals of HIT when compared to prolonged moderate-intensity exercise, and the citrate synthase and muscle glycogen increased significantly with HIT training as formatted per Burgomaster, it seems reasonable to assume that citrate synthase, muscle glycogen and endurance would improve, as well.

The downside? Tabata-style interval training is hard. It is grueling to keep pushing hard through four minutes of “flat out” physical effort.

The benefits? You will notice nearly immediate results, workouts take very little time, you will make considerable improvements in your overall health, you will see body fat loss and increased energy, and big changes in your aerobic and anaerobic capacities that transfer well to sports and physical activities. Many athletes who have reached performance plateaus will see gains in their fitness and performance.

How to do Tabata-style training

1. Use eight 20-second intervals of high to maximal effort with 10-second rest periods between them.
2. Train one to five times a week, depending on your fitness levels and goals (you should feel completely recovered before using the HIT intervals again).
3. Increase the training intensity as your fitness improves.
4. Consult with your physician before embarking on this, or any other, exercise program.
5. Use any large muscle exercise that stresses the cardiovascular system — running, biking, swimming, high-repetition free-weight training (snatches, swings, clean and press, etc.) or calisthenics.

Mark Force, D.C., is a chiropractic physician at The Elements of Health in north Scottsdale, Ariz. He practices functional and natural healthcare and is the author of Choosing Health: Dr. Force’s Functional Selfcare Workbook. 480-563-4256 or theelementsofhealth.com.

Reprinted from AzNetNews, Volume 25, Number 3, June/July 2006.