Extremely high level intensity of Tabata-style workouts may be effective for cardio fitness

Can an effective cardiovascular workout be done in 20 minutes or less? Depending on level of intensity, yes it can, according to a recent study of Tabata-style workouts commissioned by American Council on Exercise (ACE).

In the new independent study, researchers tested the intensity and calorie burn of these interval training workouts, which originated with the Japanese Olympic speed skating team and have grown increasingly popular among the public.

"An effective cardiovascular and muscular-conditioning program can be accomplished in a short period of time, but only if the level of intensity is extremely high," said ACE Chief Science Officer Dr. Cedric Bryant. "The good news is those who are relatively fit but pressed for time can use a Tabata-type program to squeeze in a workout without spending hours in the gym."

The University of Wisconsin-La Crosse's Department of Exercise and Sport Science research team used a modified Tabata protocol to create its own 20-minute, full-body workout consisting of push-ups, split squats, box jumps, burpees, jumping rope, jumping jacks and the like. The team recruited 16 healthy, moderately to very fit male and female volunteers, ages 20 to 47. All subjects first underwent a treadmill test to determine maximal heart rate (HR) and maximal aerobic capacity (VO₂ max), with ratings of perceived exertion (RPE) assessed at the end of each stage.

Each participant then completed a 5-minute warm-up followed by four rounds of a Tabata-style circuit (eight reps of 20 seconds of work, followed by 10 seconds of rest) with 1-minute of rest between each round, and a 10-minute cool down. During the 20-second phase of high-intensity exercise, subjects performed as many repetitions as possible. HR was monitored throughout, while blood lactate levels were tested with a finger prick blood test after every 4-minute segment of exercise. RPE was also evaluated after each four-minute segment. In all, each subject completed two 20-minute Tabata-style workouts.

Subjects averaged 86 percent of HR max and 74 percent of VO₂ max - both of which meet or exceed established industry guidelines for improving cardio fitness and modifying body composition. Additionally, the participants burned between 240 and 360 kcals during the workout, again meeting established guidelines for caloric expenditure for improving health and facilitating weight loss.

"There is no such thing as a miracle workout," Bryant said. "While Tabata-inspired workouts are shorter, they are also extremely tough. This study showed that fit participants perceived the workout as hard, therefore these type of workouts could be demotivating or too challenging for those not as accustomed to strenuous bouts of exercise."