Exercise a bit, rest a bit, exercise a bit more. Researchers think training in bursts, and relaxing in between, beats long, steady sessions of aerobic exercise.
But the Harvard and Columbia doctors who think the idea has merit also realize they must overcome doubts raised by the checkered past of its prime supporter, Irving Dardik. In 1995, Dardik lost his New York state medical license over his beliefs about how the body responds to exercise.
Dardik believes his system of alternating intense bursts of exercise with recovery breaks can show at least as much physiological benefit as doing distance running or walking.
The training teaches the body to react to stress and recover from it, Dardik said. By adapting to this cycle of ups and downs, the heart increases its variability, he said. And earlier work by other researchers has shown that people with hearts that have a greater ability to vary their response to stress also have lower rates of heart disease and death, he said.
"This is, to me, the revolution that we have been waiting for," said Dardik, a former vascular surgeon who runs a self-named research institute in Califon, N.J. "Aerobics is going to be a historical entity that people will look back on."
Dardik's focus on exercise follows a passion that led to the loss of his New York license. Patients told the Board for Professional Medical Conduct that Dardik had promised them the technique could cure their multiple sclerosis, an incurable degenerative disease of the nervous system. The board ordered his license revoked.
Dardik's run-in with the state doesn't make all of his ideas wrong, said the study's lead author, Dr. Rochelle Goldsmith of Columbia University College of Physicians and Surgeons. "He has a lot of good ideas in there, but they are lost," she said. "We want to find the ones that are worthwhile and worth testing."
Dr. Ary Goldberger of the Harvard School of Medicine, a co-researcher, said, "The study is the study; it speaks for itself."
"The idea is not connected with what the New York board said," Goldberger said. "This is testing in a group of healthy people."
The study used Dardik's system for calculating individual heart rates, but the nurses who volunteered were not associated with his institute, and the experiment was done independently, at Columbia, Goldsmith said.
Goldsmith, Goldberger and their colleagues report, in the preliminary study, that Dardik's system of no-sweat training produced improvements equivalent to aerobics with far less effort. Some experts caution, however, that the findings must be repeated in other studies before it is safe to advise people to switch from current aerobics-based guidelines.
In the study, 10 initially sedentary nurses ran in place on a trampoline or did bicycle exercise three days a week for eight weeks. Instead of the usual 20 minutes or more of aerobic exercise, followed by a cool-down, they exercised one minute or less.
After the exercise had pushed up their heart rates to a predetermined peak, set individually, they would take a deep breath, sit down and relax until their heart rates returned to normal. On each training day, they would repeat this exercise-and-rest cycle in sets of four to seven.
After eight weeks, the women improved their ability to use oxygen by more than 15%, the study said. And their diastolic blood pressure--taken when the heart has relaxed after a contraction--was more than 7% lower.
The exercise itself was intense--women rated it about as intense as they could stand, according to the study. But the women seemed to enjoy it, instead of hating it as many do in aerobics, Dardik said.
This might be because the women spent so little time in the intense workout that they didn't even break a sweat, Dardik said. "In any exercise session lasting 30-45 minutes, the amount they fully exercised was 5 1/2 to 6 minutes," Dardik said. "The rest was recovery. They weren't overburdened."
Goldsmith said, "The convenient thing about this is that you don't have to work up to the point of a sweat, or having to change your clothes.
"It was 67 minutes per month, where regular exercise would be 67 minutes per week. If you make it high intensity, short duration, people seem to like that," she said.
Although eight of the 10 women studied have stuck with the program for eight months after it ended, Goldsmith said more research is needed to determine the long-range benefits.
Goldsmith, Goldberger and other experts say the findings are not strong enough for them to recommend the system to the public. "This is an early presentation of an observational study," Goldberger said.
Current federal guidelines call for doing at least 30 minutes of moderate exercise such as brisk walking on most days of the week, and the new data are not enough to change that, said David Buchner, chief of the physical activity and health branch at the Centers for Disease Control and Prevention. He is not connected with the study on cyclic exercise.
If there is something to Dardik's new approach to exercise, it will have to be contrasted to his previous one on multiple sclerosis, said Dr. Stephen Barrett, a retired psychiatrist who runs the Quackwatch.com online database on health fraud.
"If you read the complaints, we are not talking about a tendency to hype things," Barrett said. "That's not hyping, that's called criminal activity."
Just the same, past practice doesn't rule out the possibility that Dardik now has something worth investigating, Barrett said. "In theory, whatever he has, he is applying to something to do with physiology," Barrett said. "In the past, he said this has to do with curing disease, which it didn't--and making huge amounts of money."