The best exercise for many of us may not be the shortest, according to a provocative new study comparing the health benefits of short, intense interval workouts to those of longer, gentler workouts.
The study, published in Medicine and Science in Sports and Exercise, concludes that while any approach to exercise has its advantages, the effects on blood pressure, body fat and other aspects of metabolism may be greater after standard workouts, half an hour and moderately, then fast interval workouts.
As those of us who track fitness know, high-intensity interval training, or HIIT (High Intensity Interval Training), is enticing, fashionable, and a common topic in this column, as is the science of exercise.
HIIT, a mix of extremely short periods of intensive exercise Followed by a minute or two of rest, it’s fast and powerful, and studies show that a few minutes – or even seconds – of interval training can improve people’s health and longevity over time.
But there are still many unanswered questions about the relative benefits of fast intervals over more traditional sustained aerobic workouts, such as brisk walking, running or cyclingEspecially if someone is only engaged in one type of exercise and not the other.
Regular moderate exercise has been linked to improvements in blood pressure and glucose control. Photo Shutterstock.
Recently, sports scientists at the University of Guelph in Ontario began to study how people’s bodies change when they exercise exclusively with intervals or standard and moderate exercise, according to current exercise guidelines.
Interestingly, many previous studies comparing short HIIT routines and longer moderate workouts did not adhere to formal training recommendations because scientists wanted to match the frequency of workouts or other measures. Thus, the volunteers in these studies trained three times a week, either completing HIIT for a few minutes or walking briskly for half an hour.
But the exercise guidelines for each type of activity differ. Medical and sports groups suggest that we exercise at intervals no more than three times a week every day muscle overload and cardiovascular systems, which means that if we train with HIIT alone, we are inactive about four days a week. Similar guidelines for moderate exercise suggest getting out and moving at least five times a week and at least 30 minutes each time.
So the Guelph scientists thought, What if people do HIIT three days a week and the other four don’t exercise, or exercise moderately five times a week?
To find out, they first recruited 23 seated and overweight adult men. They don’t include women, out of concern that menstrual cycles might affect metabolic results, but they hope to include women in a bigger experiment in the future.
They invited these men to the lab, measured their fitness, body composition and blood pressure, and asked them to drink high-fat shakes to see how their metabolism responded to the nutrient. They also provided them with blood sugar meters to wear home for a week to measure their daily blood sugar, a measure of metabolic health.
Then they asked half of the men to start interval training three times a week on stationary bikes in the lab, Pedal as hard as possible for 30 seconds, rest for two minutes and repeat that sequence four to six times.
The other men began a typical moderate exercise program, cycling in the lab five times a week at a pace they could easily maintain. for 30 to 40 minutes.
Over the next six weeks, the HIIT group cycled vigorously for less than an hour in total, while the moderate-intensity group trained at least 2.5 hours per week for the same period.
At the end of the six weeks, both groups returned to the lab for further testing, after which the scientists examined the results for differences. They found many.
Differences
Almost all men were fitter, and more or less to the same degree, regardless of the exercise they had done. But only those in the moderate exercise group had lost a lot of fat body, their blood pressure had improved or were better able to metabolize the extra fat from the smoothie.
Perhaps most interestingly, everyone’s home blood sugar was only better on the days they exercised, that is, three times a week for those who did HIIT and five times a week for the moderate group. For the rest of the days, the blood sugar tended to rise.
Taken together, the results indicate that intervals and traditional exercise change our bodies in different ways, and we may want to consider what we hope to achieve with exercise when choosing the best way to do it, says Jamie Burr, a professor at the US. University of Guelph. , who conducted the new study with his graduate student Heather Petrick and other colleagues.
“All exercises are good”Burr said. But “there are nuances.” Frequent, almost daily moderate exercise may be preferable for improving blood pressure and continuous blood sugar control, compared to irregular intervals, he says, while a little HIIT will likely get you in shape with the same efficiency as pedaling hours and hours easier. or a similar effort.
Of course this study was small-scale and short term, and only overweight and out of shape men took part, so we can’t be sure that the results apply to the rest of the population. But the most important lesson seems broadly applicable.
“ Move often, ” Burr said, which meant if you do HIIT today, you’ll walk tomorrow.
Por Gretchen Reynolds © The New York Times