Researchers found subjects who engaged in 1 minute of intense cycling three times a week showed significant health benefits.
Lead author Martin Gibala, professor of kinesiology at McMaster University in Ontario, Canada, and colleagues recently published their findings in the journal PLOS One.
The 2008 Physical Activity Guidelines for Americans recommend that adults engage in at least 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity aerobic exercise each week, or a combination of the two.
However, according to the Centers for Disease Control and Prevention (CDC), less than half of adults in the United States meet these guidelines.
While the reasons for not exercising vary, "lack of time" is one of the most common, especially with Americans' increasingly busy lifestyles.
But the new research from Prof. Gibala and colleagues challenges this excuse, after finding just short bursts of intense exercise are just as beneficial as longer endurance training.
'Brief bursts of exercise are remarkably effective'
In a previous study, the researchers found that sprint interval training (SIT) produced significant health benefits.
This 10-minute training program included three 20-second "all-out" cycle sprints, performed in between 2 minutes of low-intensity cycling. The program also included a 2-minute warm-up and a 3-minute cool down.
"This is a very time-efficient workout strategy," notes Prof. Gibala. "Brief bursts of intense exercise are remarkably effective."
For the new study, the team compared the SIT program with a moderate-intensity continuous training (MICT) program. This 50-minute program included a 2-minute warm-up, followed by 45 minutes of continuous cycling at a moderate pace, and a 3-minute cool down.
The researchers enrolled 27 sedentary men to their study, all of whom were matched for age, body mass index (BMI), and VO2 peak - a measure of the maximum rate of oxygen consumption during aerobic exercise.
Some of the men were required to engage in three weekly sessions of either SIT or MICT for 12 weeks, while the remaining men were assigned to a control group that did not exercise.
SIT just as effective as MICT
At the end of the 12-week training period, the researchers found that both the SIT and MICT groups experienced similar health benefits from their exercise regimes, compared with the control group.
In detail, both groups showed improvements in cardiorespiratory fitness, insulin sensitivity - how the body regulates blood sugar - and levels of mitochondria in skeletal muscle.
Mitochondria are the "powerhouses" of cells, and reduced mitochondrial content in skeletal muscle has been linked to poor insulin sensitivity and metabolic health.
Based on their findings, Prof. Gibala and colleagues suggest that engaging in just 1 minute of vigorous exercise three times a week is just as beneficial as the recommended 150 minutes of moderate-intensity exercise a week.
"Most people cite 'lack of time' as the main reason for not being active. 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."