Moderate Exercise Likely Curbs Kidney Decline in Sedentary Older Adults

By Marilynn Larkin

May 13, 2022

NEW YORK (Reuters Health) - A structured moderate-intensity physical activity and strength/flexibility program slowed kidney function decline compared with health education, an analysis of a randomized clinical trial suggests.

"The amount of physical activity required to improve kidney function was small," Dr. Michael Shlipak and Dr. Anoop Sheshadri, both of the University of California, San Francisco, told Reuters Health by email. "The average difference in daily step count between the two groups was only approximately 500 steps at year one and 400 steps at year two, and nearly all participants walked less than 5,000 steps per day."

"Interestingly," they added, "the effects of physical activity seemed to be independent of any changes in blood pressure or weight."

"Clinicians should strongly consider prescribing physical activity and moderate-intensity exercise for older adults to slow the rate of decline of kidney function, among other health benefits, particularly because lifestyle interventions like this one avoid the possible harms of medication side effects," they said.

"It is important to clarify that the intervention was not solely walking, but also included strength and flexibility exercises," they added. "With proper supervision, the LIFE study shows that this type of intervention is feasible even in older, sedentary adults."

As reported in JAMA Internal Medicine, Drs. Shlipak, Sheshadri and colleagues assessed whether the moderate-intensity exercise intervention could affect the rate of estimated glomerular filtration rate per cystatin C (eGFRCysC) change in 1,199 older adults (mean age, about 79; about 67% women; about 73%, white) who participated in the Lifestyle Interventions and Independence For Elders (LIFE) randomized clinical trial.

The intervention arm had undergone a structured, two-year, partially supervised, moderate-intensity physical activity and exercise (strength, flexibility); the health-education control arm consisted of weekly workshops. Physical activity was measured by step count and minutes of moderate-intensity activity using accelerometers.

At baseline, both groups were well balanced by age, comorbidity, and GFRCysC. Participants were followed for two years.

The physical activity and exercise intervention resulted in a statistically significantly lower decline in eGFRCysC compared with the health education arm (mean difference, 0.96 mL/min/1.73 m2) and lower odds of rapid eGFRCysC decline (odds ratio, 0.79).

The authors note in the paper, "The observational analyses found that moderate-intensity physical activity and exercise have a beneficial association on eGFRCysC that appears linear. Even small increases in steps were associated on average with a slowing of eGFRCysC decline, and the beneficial effects appeared to increase incrementally with participant effort."

Dr. Julia Blank, a family medicine physician at Providence Saint John's Health Center in Santa Monica, California, commented on the study in an email to Reuters Health. "The previous anecdotal reports and observational studies showing that increased exercise slows decline in renal function," she said, and they mirror what she sees in her practice.

However, she noted, "The study had few participants with advanced chronic kidney disease, and was under-represented in participants who were not white. Also, the study was limited to a two-year follow-up, so it is not known whether the beneficial effects of physical activity would increase or plateau/diminish during longer follow-up."

Further, she added, the intervention (included) two measures of activity - the step count and a measure of time in moderate intensity activity/strength training. It is unclear which component is more beneficial for kidney function, or whether both are necessary."

The study provides "more proof that encouraging your patients to exercise leads to improved health outcomes," she said. Nevertheless, she added, "Outside of a clinical study,...consistent exercise is hard to implement and sustain over the long run, especially in a population that is primarily sedentary, and often limited by other health problems including orthopedic limitations, cardiovascular disease, cognitive decline etc."

SOURCE: JAMA Internal Medicine, online May 2, 2022.