Of time and effort PDF Print E-mail
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Written by Karel Nunnink   

Say what? We’ve been told that building and maintaining fitness requires hours of training. Maybe not. A study reported in PLOS ONE on May 29, 2013, challenged that assumption. Dr. Richard Winett, who encouraged and participated in the study, stated that the “challenge to existing dogma” was such that it delayed publication. Winett’s work had suggested that a short, single bout of exercise was sufficient.

Researchers led by Arnt Erik Tjønna, a postdoctoral fellow at the KG Jebsen Center for Exercise in Medicine at the Norwegian University of Science and Technology, found that four minutes of vigorous exercise three times a week may be enough to be fit and healthy. Importantly, the study compared two time-efficient forms of training—a single sprint and four intervals of the same duration.

“Our study demonstrated that slightly overweight and healthy individuals only require brief duration bouts of exercise with good effort three times a week to produce large increases in VO2max and reduce blood pressure and fasting glucose levels,” Tjønna et al concluded.

Current public health guidelines generally recommend at least 150 minutes a week of moderate intensity exercise or a minimum of 20 minutes of vigorous exercise at least three times a week. The optimal intensity and volume is still the subject of dispute. “A growing body of evidence suggests that exercise training with low-volume but high-intensity may be a time-efficient means to achieve health benefits,” Dr. Tjønna and his team wrote in introducing the new study.

To further that line of inquiry, the researchers measured changes in VO2max and traditional cardiovascular risk factors in 24 inactive but otherwise healthy overweight men, after a 10-week program of high-intensity exercise three times a week. One group of 13 followed a protocol that had previously been shown to be effective—four intervals of 4 minutes at 90% of maximum heart rate with 3 minutes of active recovery at 70% of HR maximum (4x4). The remaining men did one 4-minute sprint at 90%; that was the extent of their high intensity exercise.

Both groups did a 10-minute warm-up and a 5-minute cooldown. Total time was therefore 40 and 19 minutes, respectively.

The results were encouraging for busy people everywhere.

VO2max improved by 10% in the single sprint group and 13% in the 4x4 group. The slight advantage reversed on the cardiovascular risk factors. The improvement in blood pressure was greater in the sprint group than in the 4x4 group, especially in systolic pressure (the top #), which improved 7.1 and 2.6 mmHg, respectively. Diastolic pressure (the bottom #) improved by 7.7 and 6.1, respectively. Fasting blood sugar declined by about 6% and 5%, with the edge again going to the sprint group. Overall, it was a statistical draw; one sprint and four produced essentially the same benefits.

The practical applications in daily living are large and varied, say the researchers. Single bouts of exercise in many forms can produce the same or similar benefits. Two examples they gave are walking quickly uphill or upstairs several times a week. The only limit is your imagination. Biking, rowing, and swimming are other good options.

Citing numerous studies, the researchers noted that most individuals can perform this type of exercise without adverse consequences, including obese and overweight individuals and those with cardiovascular disease. It would, of course, be wise to check with your doctor first. As in all forms of exercise, it is important to feel your way along and increase vigor and intensity as your condition improves.

The groups were, of course, small and more study will be required. “However, the results suggested that short duration, but intense training can yield favorable, potentially risk reduction benefits,” Tjønna and his team wrote.

The “no time to exercise” excuse is becoming less credible all the time. The more relevant question is becoming whether you are willing to exert "good effort" on a regular basis. Make vigorous activity a regular part of your week and you’ll be way ahead in the pack.

live long and strong.

source, Clarence Bass, www.cbass.com


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