Getting enough physical activity can help older people with HIV shrink their waistline and reduce fat accumulation in the liver, according to two recent studies. Weight gain is a growing concern for HIV-positive people. The accumulation of visceral fat within the abdomen—indicated by a large waistline—is particularly detrimental to health.

The first research team assessed the association between physical activity and abdominal fat in 416 people (average age 58) with well-controlled HIV. The participants used an accelerometer to record their physical activity for about a week. After controlling for other factors, waist circumference was about 1 centimeter smaller for every additional 1,000 steps per day. Conversely, a greater amount of daily sedentary, or inactive, time was associated with a larger waistline.

In the second study, researchers looked at the link between physical activity and liver fat accumulation, or steatosis, among 466 people (median age 52) in the Swiss HIV Cohort Study. Transient elastography screening showed that half had at least moderate liver steatosis, and a third had severe steatosis; even among lean individuals, nearly a third had steatosis. After controlling for other factors, people who did not get the recommended amount of physical activity were more than twice as likely to have steatosis. What’s more, the likelihood of steatosis rose with each additional hour of daily sitting time.

“Future work should investigate how to tailor the amount, type and intensity of physical activity needed to reduce adiposity in people with HIV taking contemporary HIV medication,” Allison Webel, RN, PhD, of the University of Washington School of Nursing, and colleagues wrote.