Evidence for High Intensity Interval Training to be More Beneficial than Moderate Exercise in the Elderly
Researchers here report on the results five years in to a study comparing the effects of different exercise programs on mortality in older people. While the high intensity interval training group are clearly doing well in comparison to their peers, there is a cautionary tale in study design for the other two groups, in that the control individuals appear to have been inspired by their inclusion in the study to exercise more than the study participants who were assigned to the moderate intensity training group. Taken as a whole, the results nonetheless provide yet more corroborating evidence for exercise to reduce mortality in later life.
Can exercise really give older people a longer and healthier life? Generation 100 is the first major study that can tell us that, and researchers have encouraging news. Among most 70-77-year-olds in Norway, 90% will survive the next five years. In the Generation 100 study, more than 95% of the 1500 participants survived. The Generation 100 study is a cause-and-effect study. This means that all participants were divided completely randomly into three different training groups when the study started in 2012.
One group was assigned to do high-intensity training intervals according to the 4×4 method twice a week, while group two was instructed to train at a steady, moderate intensity for 50 minutes two days a week. The participants could choose whether they wanted to train on their own or participate in group training with instructors. The third group - the control group - was advised to exercise according to the Norwegian health authorities' recommendations. This group was not offered organized training under the auspices of Generation 100, but was called in for regular health checks and fitness assessments.
Both physical and mental quality of life were better in the high-intensity group after five years than in the other two groups. High-intensity interval training also had the greatest positive effect on fitness. "In the interval training group, 3% of the participants had died after five years. The percentage was 6% in the moderate group. The difference is not statistically significant, but the trend is so clear that we believe the results give good reason to recommend high-intensity training for the elderly. Among the participants in the control group, 4.5% had died after five years. One challenge in interpreting our results has been that the participants in the control group trained more than we envisioned in advance. One in five people in this group trained regularly at high intensity and ended up, on average, doing more high-intensity training than the participants in the moderate group. You could say that this is a disadvantage, as far as the research goes. But it may tell us that an annual fitness and health check is all that's needed to motivate older people to become more physically active."
Link to paper: https://www.bmj.com/content/371/bmj.m3485
Pro: best study I've seen regarding exercise vs mortality
Cons: those dropout rate differences (33% for HIIT, 26% for MICT and 20% for control) could explain away the whole thing as a self-selection side-effect