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High-intensity interval training safe, effective for older adults
PHILADELPHIA — Compared with moderate-intensity continuous training and controls who received advice based on national physical fitness standards in Norway, 5 years of supervised high-intensity interval training was associated with improved rates of all-cause mortality in older adults.
However, the high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) groups combined (4.5% mortality rate) did not achieve improved all-cause mortality compared with the control group (4.7% mortality rate), according to findings presented at the American Heart Association Scientific Sessions.
Moreover, researchers found a trend toward risk reduction for all-cause mortality after HIIT (HR = 0.63; 95% CI, 0.33-1.2) but not after MICT (P = .43) compared with controls.
“Supervised exercises combined and compared to controls showed no effect on all-cause mortality, cardiovascular events or cancer events in older adults, and we observed a lower risk of all-cause mortality after HIIT compared to MICT,” Dorthe Stensvold, PhD, associate professor and researcher at K.G. Jebsen Center for Exercise in Medicine, department of circulation and medical imaging at the Norwegian University of Science and Technology, said during her presentation. “We also tended to see lower all-cause mortality after HIIT compared to controls.”
Compared with the MICT group, the HIIT group had an approximately 50% risk reduction (HR = 0.51; 95% CI, 0.25-1.02) for premature all-cause mortality, according to the study.
In other findings, there were no differences between the groups in cancer and CVD events.
Researchers invited all men and women born between 1936 and 1942, living in Trondheim, Norway, to participate in their study evaluating 5 years of supervised exercise on mortality. Participants (n = 1,567; 790 women; mean age, 73 years) were randomly assigned to one of three groups to undergo 5 years of two weekly sessions of HIIT at 90% of peak heart rate, two weekly sessions of MICT at 70% of peak heart rate or to a control group receiving national recommendations of physical activity.
“Importantly, this is the first study showing that high-intensity interval training is a safe, effective and feasible exercise in older adults,” Stensvold said during the presentation. – by Scott Buzby
Reference:
Stensvold D, et al. Implementation Science Around the Globe. Presented at: American Heart Association Scientific Sessions; Nov. 16-18, 2019; Philadelphia.
Disclosures: The authors report no relevant financial disclosures.
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What was interesting in terms of a hypothesis-generating finding was that there was a 37% relative risk reduction for the high-intensity interval training group compared with controls. That’s a large risk reduction, but it was not statistically significant. I imagine the study wasn’t powered to look at a significant difference in the high-intensity group. The authors may be suggesting that high-intensity interval training is effective, whereas moderate-intensity continuous training is not. But that can’t be confirmed by this study. The primary outcome was negative.
The overall incidence of death in the sample was relatively low. Fewer than 5% of people, with a mean age of 73 years, died over 5 years. That’s a low number. If you look at the general population of older people, it’s much higher. That suggests to me that there‘s a healthy cohort bias, ie, people who sign up for this study are healthier than the average population. I don’t know if these results are applicable more broadly. What they might suggest is that if you take patients who are relatively healthy with a low predicted mortality rate and you perform structured exercise with them, it’s no better than the control group of people adhering to national exercise guidelines.
I do research in cardiac rehab and we know from decades of research that cardiac rehab works in people with specific conditions. After MI, after bypass surgery, there’s no question that it’s beneficial. What this study brings up is that if you take all these people and you put them in a structured exercise program, it might not be effective. We need a more precision approach perhaps, which is exactly what we do clinically. Based on this, I wouldn’t tell people not to exercise, because even in the control group, they received recommendations on exercise based on national guidelines. In the U.S., the guidelines are relatively specific. So, they say 150 minutes per week and if you achieve that 150 minutes, you increase to 300 minutes. For older people, sometimes it’s difficult to reach that target.
I would say to do what you can. In addition to the exercise, it’s good to do some resistance training to strengthen muscle groups to lower the risk of things like falls.
