Higher physical activity levels linked to less belly fat

Thanks to the power of HIV treatment (antiretroviral therapy, ART), researchers predict that many ART users will live long and healthy lives, well into their senior years. However, as everyone ages, regardless of HIV status, issues associated with aging begin to appear. These can include high blood pressure, diabetes, cardiovascular disease and, in some cases, weight gain.

It is normal for people to gain some weight as they grow older—they may engage in less physical activity, metabolism slows down and there are hormonal factors as well. To counter this, increased aerobic exercise, building muscle mass and implementing dietary changes may be necessary. Compared to studies of pills or injections, there are far fewer well-designed studies on the effect of exercise in people with HIV. Such non-pharmaceutical studies are complex and not prioritized for scarce research funds.

Despite this, a team of researchers at the University of Washington (in Seattle) and several other academic-medical centres in the U.S. conducted a short-term (about one week) study using wearable high-precision devices (accelerometers) that measured physical activity in participants.

In analysing the data from 419 participants with HIV, researchers found that people who were physically active (more steps per day) tended to have the least amount of belly fat. The converse was also true—people who had the least amount of physical activity had the greatest amount of belly fat.

The researchers encouraged the development of studies to find the right amount of exercise needed to help people minimize their belly fat.

The fat that is deposited deep in the belly is called visceral fat. This fat wraps itself around organs and over the long term can contribute to poor health. Exercise has many benefits, including the following:

• it releases chemical signals that can help burn stored fat
• it enhances mood and memory
• it is good for cardiovascular health

Building up muscle is important because as people age they tend to lose muscle. Muscle helps maintain overall health and can burn fat. In addition, by engaging in more physical activity people can build up their endurance and ability to carry out desired everyday activities.

Study details

Researchers recruited participants from the following cities:

• Boston, MA
• Birmingham, AL
• Cleveland, OH
• Seattle, WA

Study staff used simple time-tested ways to estimate belly fat, including measuring waist size and the waist-to hip-ratio.

Physical activity was measured with the ActiGraph accelerometer. Participants wore this device while awake (except for when bathing or swimming) for at least 10 hours per day, for between seven and 10 days.

The average profile of participants was as follows:

• 58 years
• 23% female, 77% male
• major ethno-racial groups: Black – 54%; White – 44%
• years taking ART – 14
• most participants were taking regimens based on an integrase inhibitor (such as bictegravir, dolutegravir or elvitegravir)
• body mass index (BMI) – 28 kg/m²
• co-morbidities: high blood pressure – 77%; reduced kidney function – 40%; diabetes – 33%; cardiovascular disease – 22%

Results

On average, participants took nearly 5,000 steps per day. Researchers found that almost 55% of participants did either 150 minutes per week of moderate-to-vigorous physical activity or 75 minutes per week of vigorous physical activity.

Researchers took into account factors such as sex, employment, age and so on when further analysing their data. They found that the more steps a person walked each day, the more likely they were to have a smaller waist. The researchers found that the time participants spent on moderate-to-vigorous physical activity was not linked to waist size.

The researchers recommended that healthcare providers assess patients’ physical activity and prescribe exercise, such as the following:

• join a walking group
• undergo supervised exercise training
• join a community exercise program

For the future

The present study should be seen as building a foundation for a research program. Next up are longer studies to assess the impact of different types of physical activity and their duration and intensity on belly fat in people with HIV. Such studies can yield targeted recommendations for different people.

—Sean R. Hosein

REFERENCES:

1. Lee D. The importance of exercise and physical activity in older adults with HIV. AIDS. 2023 Oct 1;37(12):1905-1907.
2. Webel AR, Davey CH, Oliveira V, et al. Physical activity is associated with adiposity in older adults with HIV in the modern HIV era. AIDS. 2023 Oct 1;37(12):1819-1826.