Study Finds that Breaks in Between Exercise Periods Burns More Fat

In a new study from Japan published in the Journal of Applied Physiology, scientists have found that taking short breaks in between moderate endurance exercise bouts, tends to burn more fat than a single long period of moderate exercise.

The study was conducted by Kazushige Goto, academic with the Department of Life Sciences in the Graduate School of Arts and Sciences at the University of Tokyo in Tokyo, Japan and Kaoru Takamatsu, affiliate of the Institute of Health and Sport Sciences in the University of Tsukuba in Ibaraki, Japan.

The study basically compared the efficiency of fat metabolism between single bouts of prolonged exercise against repeated periods of exercise activity. The exercise conducted in both sessions was of the same intensity and duration.

To compare the energy and metabolic expenditure of both of these regimens, researchers recruited seven men that performed 3 distinctive trials. One of them consisted of a single period of exercise executed during 60 minutes. Another was comprised of two bouts of 30 minute exercise periods divided by a 20 minute break. The last trial included just rest.

A cycle ergometer (to measure energy use) was utilized in each exercise regimen at 60% of maximal oxygen uptake. In each of the exercise trials, the research team measured several markers of metabolic activity such as serum glycerol, growth hormone, plasma epinephrine (adrenaline), and nor-epinephrine.

The research team found that in both exercise regimens, the level of biomarkers increased considerably during the first 30 minutes of exercise.

When they evaluated the repeated trial, the found that serum free fatty acids (FFA) and 3-hydroxybutyrate (markers of fat metabolism) increased rapidly in the 20 minute rest period. Even more remarkably, during the second 30 minute bout of exercises, the markers of fat metabolism were higher in the repeated trial sessions as compared to the single trial regimen. In addition, the researchers also reported that the repeated trial had lower insulin and glucose (higher sugar metabolism efficiency) values.

A careful assessment of the 60 minute recovery period revealed that the levels of FFA, glycerol, and 3-hydroxybutyrate were considerably higher in individuals that had undergone the repeated trials as compared to the single bout regimens. The researchers affirmed that this translated into a higher fat oxidation (and therefore fat metabolism) contribution in the exercise sessions divided by a 20 minute rest period.

In the press release from the American Physiology Society (APS), Dr. Goto state that "Many people believe prolonged exercise will be optimal in order to reduce body fat, but our study has shown that repetitions of shorter exercise may cause enhancements of fat mobilization and utilization during and after the exercise. These findings will be informative about the design of (future) exercise regimens. Most people are reluctant to perform a single bout of prolonged exercise. The repeated exercise with shorter bouts of exercise will be a great help (in keeping up with fitness)."

As per the APS release, they commented that the American College of Sports Medicine currently recommends moderate exercise of 45 to 60 minutes of duration to make sure that sufficient energy is expended by individuals that are obese. Moreover, there are also public recommendations that emphasize only single 30 minute periods of exercise (a day) for proper weight loss. Now however, this notable study shows that single periods of exercise endurance may not be the most efficient way to burn fat.

The APS remarked that this study may lead to new methodologies and practical applications on how to best lose weight via exercise.

Sources:

The American Physiological Society: http://www.the-aps.org/press/journal/07/40.htm

The American College of Sports Medicine: http://www.acsm-msse.org/pt/re/msse/positionstandards.htm;jsessionid=GfQYNYjG2MTpyyGCgyCPzFmF2mn233hykJ7TJrnTQn0qrxlLgFvH!675572714!181195628!8091!-1

Journal of Applied Physiology: http://jap.physiology.org/cgi/content/abstract/102/6/2158