Whats the single best exercise?

Well,no. The butterfly would probably get my vote for the worst exercise,said Greg Whyte,a professor of sport and exercise science at Liverpool John Moores University in England and a past Olympian in the modern pentathlon,known for his swimming.

The butterfly,he said,is miserable,isolating,painful.

Ask a dozen physiologists which exercise is best,and youll get a dozen wildly divergent replies. Trying to choose a single best exercise is like trying to condense the entire field of exercise science,said Martin Gibala,the chairman of the department of kinesiology at McMaster University in Hamilton,Ontario.

But when pressed,he suggested one of the foundations of old-fashioned calisthenics: the burpee,in which you drop to the ground,kick your feet out behind you,pull your feet back in and leap up as high as you can. It builds muscles. It builds endurance. He paused. But its hard to imagine most people enjoying an all-burpees program,or sticking with it for long.

I personally think that brisk walking is far and away the single best exercise, said Michael Joyner,MD,a professor of anesthesiology at the Mayo Clinic in Rochester,Minn.,and a leading researcher in the field of endurance exercise.

Walking has also been shown by other researchers to aid materially in weight control. A 15-year study found that middle-aged women who walked for at least an hour a day maintained their weight over the decades.

But lets face it,walking holds little appeal or physiological benefit for anyone who already exercises. I nominate the squat, said Stuart Phillips,Ph.D.,a professor of kinesiology at McMaster University and an expert on the effects of resistance training on the human body.

The squat activates the bodys biggest muscles,those in the buttocks,back and legs. Its simple. Just fold your arms across your chest, he said,bend your knees and lower your trunk until your thighs are about parallel with the floor. Do that 25 times. Its a very potent exercise.

The squat,and weight training in general,are particularly good at combating sarcopenia,he said,or the inevitable and debilitating loss of muscle mass that accompanies advancing age. Each of us is experiencing sarcopenia right this minute, he said. We just dont realize it. Endurance exercise,he added,unlike resistance training,does little to slow the condition.

I think that you can make a strong case for HIT, Gibala said. High-intensity interval training,or HIT as its familiarly known among physiologists,is essentially all-interval exercise. As studied in Gibals lab,it involves grunting through a series of short,strenuous intervals on specialized stationary bicycles,known as Wingate ergometers.