High-intensity exercise may amplify the health benefits of staying active in later life Digest
Few behaviors support long-term health as powerfully as staying physically active, yet scientists still debate how much intensity is optimal—especially in later life. To explore this, researchers in Norway conducted a five-year randomized trial testing whether structured workouts could lower mortality in older adults, and whether high-intensity sessions offer extra benefit over moderate-paced ones.
The trial enrolled 1,567 men and women aged 70 to 77. Participants were randomly assigned to one of three plans for five years: follow the Norwegian activity guidelines on their own as defined as 30 minutes of moderate physical activity almost every day without supervision; complete two sessions per week of moderate continuous training lasting about 50 minutes at roughly 70 percent of peak heart rate, with periodic supervised check-ins; or complete two sessions per week of high-intensity training consisting of four 4-minute intervals at roughly 90 percent of peak heart rate, with the same supervision schedule.
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After five years, mortality remained low across all groups, yet fitness and quality of life tended to be greatest in the high-intensity training group:
- After accounting for age and other factors, the high-intensity group had roughly 37 percent lower risk of death than the control group, while the moderate group had about 24 percent higher risk. However, these differences were not statistically significant.
- Rates of heart disease and cancer were similar across groups, at roughly 16 and 12 percent, respectively.
- The high-intensity group had slightly better cardiorespiratory fitness after five years, with peak oxygen uptake about 0.7 milliliters per kilogram per minute higher than the other groups. This measurement reflects how efficiently the body uses oxygen during exercise and is closely tied to longevity.
- Quality of life scores were also better in the high-intensity group, both for physical and mental well-being.
Across all groups, participants maintained their ability to take in and use oxygen during exercise, which usually declines with age. Because high-intensity training produced the greatest oxygen uptake values, it may have provided an extra physiological margin that supports longevity.
Because the participants were already quite healthy and active at the start, and only a small number of deaths occurred, the study may not have been large enough to reveal clear or statistically reliable differences between the exercise groups. Still, the results suggest that maintaining physical activity in older age can lower mortality and improve quality of life when performed safely, with higher-intensity exercise providing potential additional benefits. Learn more about the science of high-intensity exercise in episode #82, featuring Dr. Martin Gibala