Exercise to combat metabolic syndrome

HEART HEALTH: The disease of our time, metabolic syndrome, can lead to multiple disorders, including cardiovascular disease, hypertension, obesity, high cholesterol and diabetes. It’s common to recommend continuous moderate exercise for people with metabolic syndrome.

But to encourage our readers to seize the opportunity this summer to exercise smarter, not necessarily more, we’re featuring a landmark study from the NTNU Faculty of Medicine from back in 2008 which found that short, strenuous exercise intervals yielded greater health benefits than traditional exercise plans for individuals with metabolic syndrome.

Aerobic interval training can in fact be more effective than losing weight in controlling the syndrome.

The study, published in Circulation, was one of many conducted under the guidance of Ulrik Wisløff, now director of the Cardiac Exercise Research Group. The paper’s first author, Arnt Erik Tjønna, now a researcher at CERG, reported that 47 per cent of patients who did the interval training program for four months reversed metabolic syndrome—compared with 36 per cent among those who trained with constant, moderate intensity.

The training groups expended the same number of calories per workout.

This means that people who exercised at a continuous, moderate intensity had longer workouts than those who did high-intensity interval training, and that it was actually the exercise intensity that made the difference between the groups.

Reverses syndrome

To determine which exercise intensity worked best in treating metabolic syndrome, 32 patients with a mean age of 52 were divided into three groups.

One group did aerobic interval training and one trained with continuous, moderate intensity. Both groups trained three times a week for four months. The third control group received training advice from their general practitioner.

“This study shows that exercise in general, but especially interval training, is able to partially or completely reverse metabolic syndrome,” said Tjønna ,who led the study with Wisløff while he was completing his PhD at the Department of Circulation and Medical Imaging at NTNU.

Just exercising hard for four, four-minute intervals can help reduce your risk of metabolic syndrome. Photo: Thinkstock SHOW MORE

“It seems that this is a promising treatment strategy that certainly should be tested on larger groups,”  Tjønna said.

Increased training stamina

According to the researchers, the current guidelines for physical exercise may be too general for this group of people, most of whom have had an inactive lifestyle for many years.

“Our experience is that advising people to do interval training two to three times per week gets them into shape fast. The only side effect is that they build up their stamina and take up old routines like walks in the woods on weekends,  so they end up exercising more,” Tjønna says.

“In contrast, we’ve found that people who haven’t exercised in years and who are advised to train every day, can’t stick with daily training as time goes by,” he adds.

“We realize that this may seem counterintuitive to a lot of folks who believe it’s impossible for most people to train at such a high intensity, but we dare say that anyone can do it. It’s not exhausting training, but training at an intensity that’s about 20 heartbeats below the maximum for each person,” he says.

This means working with large muscles —like the ones you use for walking uphill, cycling, swimming, skiing or running —for four periods of four minutes, where you should get pretty out of breath (so it’s hard to talk), but not horribly tight in your legs. If you cannot sustain this for four minutes, it’s too hard.

“We’ve conducted similar training for elderly patients with heart failure. And given that even they can manage it, the chances are reasonably good that most people can do it,”  Tjønna said.

Conditioning more important than weight

The researchers looked at why interval training was better than other types of exercise. They found, among other things, that fitness levels increased by 35 per cent with interval training, but only by 16 per cent with other training.

At the same time patients’ hearts became stronger, improving mitochondrial function— meaning they were better able to produce “fuel” for muscles— as well as improving  vascular function and the regulation of blood glucose in blood, muscle and fat.

The researchers also found that both exercise groups reduced their weight equally.

Combined with the fact that the group who did the interval training reduced several of the risk factors associated with metabolic syndrome, this suggests that it may be more important to get into shape than to lose weight.

“Although obesity and lack of fitness both can lead to early death from cardiovascular disease, it appears that fitness is more important in preventing this,”  Tjønna said.

These findings therefore suggested hat it may be more important for health care providers to try to improve their patients’ fitness level rather than to start by treating overweight, obesity, and type-2 diabetes using other treatment principles.

Reference: Aerobic Interval Training Versus Continuous Moderate Exercise as a Treatment for the Metabolic Syndrome:A Pilot Study.2008. Arnt Erik Tjønna, Sang Jun Lee, Øivind Rognmo, Tomas O. Stølen, Anja Bye, Per Magnus Haram, Jan Pål Loennechen, Qusai Y. Al-Share, Eirik Skogvoll, Stig A. Slørdahl, Ole J. Kemi, Sonia M. Najjar and Ulrik Wisløff. Circulation, 22 July, Vol. 118:4