Longevity Briefs: Sporadic Exercise Is Associated With Longer Life

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Longevity briefs provides a short summary of novel research in biology, medicine, or biotechnology that caught the attention of our researchers in Oxford, due to its potential to improve our health, wellbeing, and longevity.

Why is this research important: It really doesn’t take much exercise to significantly improve general health and reduce the risk of age-related disease. Previous research suggests that even 10-15 minutes of brisk walking per day is associated with about 2 years of life gained (compared to a sedentary lifestyle), with increasing amounts of exercise yielding diminishing returns.

Some people prefer to concentrate most of their physical activity within a few days each week. Studies suggest that this yields similar benefits to a less sporadic routine, but some questions remain unanswered.

What did the researchers do: In this study, researchers looked at data from 3100 participants of NHANES, a health and nutrition survey looking at a representative sample of US adults. The study included participants who were asked to wear accelerometers during the years 2005 and 2006. They were then followed up for 10 years, during which mortality was recorded. In the present study, researchers wanted to see how the number of days on which participants walked at least 8000 steps (about 4 miles) related to probability of death during the followup period.

Key takeaway(s) from this research: After controlling for confounding factors like age, sex and health status, walking at least 8000 steps on a greater number of days was unsurprisingly associated with reduced mortality over the next ten years. This effect was significant even when the 8000 mark was achieved on just a few days. Reaching 8000 steps on 1-2 days was associated with a 15.9% reduction in all cause mortality relative to those who achieved that goal on 0 days, while those who reached 8000 steps on 3-7 days had a 19.4% reduction in mortality.

The % reduction in risk of death over 10 years, relative to someone who achieves 8000 steps on zero days. One column shows reduction when only age and sex are controlled for. ‘Model 1’ controls for other confounders such as smoking status and hypertension. ‘Model 2’ controls for all the same confounders as model 1, but also controls for average daily step count.
*Association of Daily Step Patterns With Mortality in US Adults*

People who achieved 8000 steps on more days may of course be more likely to have taken a greater number of steps in total. When researchers adjusted for this by controlling for average number of daily steps, the gap narrowed. Achieving 8000 steps on 1-2 days was associated with a 14.9% reduction in mortality, compared to a 16.5% reduction for 3-7 days/week. In other words, for two people taking a similar number of steps each week, it does not seem to matter that much whether those steps are concentrated over a few days or spread out over the entire week. The researchers also observed that the benefits of achieving the 8000 steps per day plateaued after 3 days per week.

This is further evidence that concentrating all of your exercise into a few days is a valid alternative to a more consistent routine, and still yields significant health benefits. However, this kind of study does tend to involve a lot of confounding factors that are hard to control for. This makes it difficult to properly compare sporadic to consistent exercise routines. At least we can say that if you only have a day or two per week to exercise, a four mile walk isn’t a bad goal to aim for. With a brisk walking pace, this is achievable in about an hour.