As mentioned previously in this issue of TreatmentUpdate, HIV infection is associated with activation of the immune system and inflammation. This inflammation is only partially suppressed with ART. Scientists are not sure why chronic inflammation occurs in HIV-positive people who use ART but suspect that it may be due to at least one of the following:
Researchers at the University of Rome (Italy) and in Atlanta (U.S.) have proposed that one potential method for helping to reduce excess levels of inflammation and dampen immune activation in HIV-positive people is exercise.
The impetus for exploring the effect of exercise comes from scientists at Harvard University who pointed out the following trends among HIV-negative people:
Even if a person is not obese, research on obesity-related inflammation underscores a previously underappreciated connection between the immune system and metabolism.
Much research has been done with HIV-negative people and exercise, and scientists have found that exercise can have many beneficial effects, including reducing the risk for type 2 diabetes and cardiovascular disease.
Studies with HIV-negative people who do not exercise have found that they are at increased risk for developing chronic low-grade inflammation. The problem of inflammation arises because many people who do not exercise tend to build up fat deep within their belly. This fat, called visceral fat, wraps itself around vital organs and produces hormones and chemical signals that favour inflammation. These hormones and signals produced by visceral fat also affect the immune system.
Scientists at several centres around the world have recently studied the impact of exercise with HIV-positive people and we now summarize such studies.
Researchers at the University of Bahia in Brazil conducted a six-month randomized, controlled study with 63 HIV-positive participants. They assigned participants to one of the following interventions:
At the end of the study, participants who engaged in regular exercise had decreases in the following assessments:
They also had increases in the following assessments:
Scientists at the Alfred Hospital in Melbourne conducted a randomized, controlled study with 35 HIV-positive men for six months that involved the following interventions:
As with some other studies, participants who received supervised fitness training had improved cardiovascular health, quality of life and cognitive function.
Some HIV-positive people experience a lack of energy and/or become tired very easily. Perhaps, for such people, a program of brisk walking may be more suitable. Researchers in Milan, Italy, enrolled 59 HIV-positive people and assigned them to one of the following interventions for 12 weeks:
At the end of this study, all participants had statistically significant decreases in their total cholesterol and bad-cholesterol (LDL-C) and in their waist size.
There were also significant decreases in levels of proteins in the blood associated with immune activation, including the following:
Thus, even modest levels of exercise can have a beneficial effect on inflammation.
People who engage in regular exercise report feeling good or even high afterward. The Italian researchers suggest that this is likely for at least the following reasons:
Based on these and other studies, more scientists are in favour of exercise programs for HIV-positive people so that fitness, quality of life, overall sense of well-being and reduction of inflammation can occur.
Long-term clinical trials are needed to assess the effects of exercise and other interventions on the overall health of HIV-positive people as well as measures of inflammation.
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