Moderate Exercise = Healthier Kidneys


If you’re sedentary, ramping up the exercise to just a moderate level may go a long way in keeping your kidneys healthier, according to a recent study in JAMA Internal Medicine.

The Lifestyle Interventions and Independence For Elders (LIFE) Study included nearly 1,200 older adults (ages 70 to 89). Half were assigned to a two-year exercise intervention group, during which time they attended twice-weekly exercise classes and did home-based activities three to four times a week, with the goal of walking 30 minutes a day (or 150 minutes a week) at a “somewhat hard” perceived exertion level; they also did daily strength, flexibility, and balance training. The other half attended weekly workshops on health topics for six months and then monthly workshops for the remainder of the study.

At various points of the study, all participants wore accelerometers for a week so the investigators could track their activity, and all participants had blood tests at baseline and after the first and second years to assess their kidney functioning.

At the end of two years, those in the exercise group had a significantly slower decline in kidney function, as measured by glomerular filtration rate (GFR), and were about 20 percent less likely to show a rapid decline in functioning, compared to the control group. Those who had the highest step counts (more than 3,470 a day) had the best outcomes, compared to those with the lowest counts (less than 1,567)—but even just a relatively modest increase in physical activity was found to be beneficial for kidney functioning, with the authors noting that “the present results show that extreme levels of activity are not necessary to slow rates of decline” of kidney functioning.

What’s more, the participants had mobility limitations but were nevertheless able to boost their activity enough to make a difference. That’s because the study prioritized walking and home-based exercise, which may be more achievable for older people with mobility issues.

Medications to control hypertension and diabetes are the primary methods used to slow declining kidney function, but lifestyle interventions would be other important options. Observational studies have suggested that physical activity can slow kidney decline, but clinical trials have been scant. The current study is notable for its large size and long follow-up, and for its focus on older, community-dwelling people.

Though the investigators did not venture an explanation as to how physical activity might have a direct effect on kidney functioning, they pointed out that physical activity and exercise have other potential benefits, including reducing several kidney disease risk factors like hypertension, cardiovascular disease, and insulin resistance/diabetes.

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