Recently, researchers from Birmingham University’s Human Performance Laboratory attempted to pinpoint the exercise intensities at which fat metabolism is maximized in a study of 18 male endurance cyclists with a training background of at least three years. The average age of the participants was 28, and their mean VO2max was 58.4 ml.min-1.kg-1.
All the subjects performed a graded exercise test to exhaustion on a cycle ergometer, starting at 95 watts and increasing their work rate by 35 watts every five minutes. Once the respiratory exchange ratio (R) reached 1.0, the work rate was increased by 35 watts every two minutes until exhaustion.
According to this study, fat prefers to release its generous energy stores during fairly leisurely efforts.
Other research has suggested that when you cycle, swim, row or run at a modest intensity of only 50% VO2max (about 65% of your maximal heart rate), fat provides about half of the calories you need to keep pottering along for the first hour or so. If you keep going after that, fat becomes even more generous, chipping in around 70% of total energy after two hours of such light exertion and 80% or more if your work duration exceeds three hours.
The recommended exertion levels – often at around 50-65% of VO2max – are sometimes said to comprise the ‘fat-burning zone’ (FBZ) of possible exercise intensities. As you can see, FBZ is very similar to the Birmingham Fatmax zone; FBZ is slightly lower on the intensity scale but encompasses most of the intensities in Fatmax.
The intensity of FBZ sessions is low, they can be sustained for very long durations; thus, even though the per-minute rate of calorie burning is puny, the total calories burned during single FBZ sessions can be monumental.
While this may not appear to be a strong selling point, it is true that an athlete who could keep exercising for only one hour at an intensity of 75% VO2max might be able to complete a full two-hour workout at the lower intensity of 50% VO2max. In the former case, 660 calories would be burned, but in the latter 880 calories would sail out the window. Seen from this perspective, FBZ training has a certain attraction – for people who have two hours to spare.
For The research article, you can see the following link :
Fat Burning : train your metabolism to use up those calories
No comments:
Post a Comment