As we age, the slow loss of muscle strength and speed can quietly chip away at our ability to live independently. A five-year study in Norway followed over 1,500 adults starting in their early 70s to see if different types of exercise could help. The group assigned to high-intensity interval training (HIIT) — short bursts of hard effort followed by rest — saw their grip strength decline less than the control group in the first few years. They also walked slightly faster at the three-year mark and had roughly half the odds of developing clinically defined sarcopenia, a condition of significant muscle loss, by years three and five.
It’s important to note that the moderate-intensity continuous training group didn’t show these advantages over the control group. And while the HIIT benefits were statistically clear, the actual differences in strength and speed were small in practical terms. For example, the grip strength advantage was about one kilogram at year one.
By the five-year mark, walking speed had declined in all groups, including HIIT, though the HIIT group’s decline was the smallest. The study didn’t report on safety issues or how many people stuck with the demanding HIIT routine for the full five years. These were relatively healthy, well-educated Norwegian volunteers, so the results might not translate to everyone. The research shows a promising signal that pushing intensity might offer an edge in preserving function, but it’s not a guarantee against age-related decline.