Exercise Intensity Seems Not to Impact Mortality Levels

Combined MICT, HIIT intervention group had no difference in mortality versus recommended guidelines

FRIDAY, Oct. 9, 2020 (HealthDay News) — Combined moderate- and high-intensity training has no effect on all-cause mortality compared with recommended physical activity levels, according to a study published online Oct. 7 in The BMJ.

Dorthe Stensvold, Ph.D., from the Norwegian University of Science and Technology in Trondheim, and colleagues conducted a randomized trial involving 1,567 individuals born between 1936 and 1942. Participants were randomly assigned to two sessions weekly of high-intensity interval training (HIIT), to two sessions weekly of moderate-intensity continuous training (MICT), or to follow the national guidelines for physical activity (400, 387, and 780 participants, respectively).

The researchers found no difference in all-cause mortality between the control group and the combined MICT and HIIT group. When MICT and HIIT were analyzed separately, there was an absolute risk reduction of 1.7 percentage points after HIIT (hazard ratio, 0.63; 95 percent confidence interval, 0.33 to 1.20) and an absolute increased risk of 1.2 percentage points after MICT (hazard ratio, 1.24; 95 percent confidence interval, 0.73 to 2.10) with the control group as a reference. A 2.9 percentage-point absolute risk reduction was seen for all-cause mortality when HIIT was compared with MICT as the reference group (hazard ratio, 0.51; 95 percent confidence interval, 0.25 to 1.02).

“Future guidelines for physical activity, at least for older adults, should be more specific in requiring that at least part of the physical activity should be performed at high intensity,” the authors write.

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