Another group began exercising moderately for longer sessions of 50 minutes twice a week. And the third group started a program of twice-weekly high-intensity interval training, or H.I.I.T., during which they cycled or jogged at a strenuous pace for four minutes, followed by four minutes of rest, with that sequence repeated four times.
Almost everyone kept up their assigned exercise routines for five years, an eternity in science, returning periodically to the lab for check-ins, tests and supervised group workouts. During that time, the scientists noted that quite a few of the participants in the control had dabbled with interval-training classes at local gyms, on their own initiative and apparently for fun. The other groups did not alter their routines.
After five years, the researchers checked death registries and found that about 4.6 percent of all of the original volunteers had passed away during the study, a lower number than in the wider Norwegian population of 70-year-olds, indicating these active older people were, on the whole, living longer than others of their age.
But they also found interesting, if slight, distinctions between the groups. The men and women in the high-intensity-intervals group were about 2 percent less likely to have died than those in the control group, and 3 percent less likely to die than anyone in the longer, moderate-exercise group. People in the moderate group were, in fact, more likely to have passed away than people in the control group.
The men and women in the interval group also were more fit now and reported greater gains in their quality of life than the other volunteers.
In essence, says Dorthe Stensvold, a researcher at the Norwegian University of Science and Technology who led the new study, intense training — which was part of the routines of both the interval and control groups — provided slightly better protection against premature death than moderate workouts alone.
Of course, exercise was not a panacea, she adds. Some people still sickened and died, whatever their workout program. (No one died while exercising.) This study also focused on Norwegians, who tend to be preternaturally healthy, and most of us, perhaps regrettably, are not Norwegians. We also may not yet be in our 70s.
But Dr. Stensvold believes the study’s message can be broadly applicable to almost all of us. “We should try to include some exercise with high intensity,” she says. “Intervals are safe and feasible for most people. And adding life to years, not only years to life, is an important aspect of healthy aging, and the higher fitness and health-related quality of life from H.I.I.T. in this study is an important finding.”