Moderate aerobic exercise improves cardiovascular and nervous system function in HIV+

03/28/05

Biking or treadmill use in HIV may be a cost-effective supplemental therapy, with improved physiological function the only side-effect

San Diego (April 3, 2005) Researchers from Teachers College, Columbia University, and Coler Goldwater Specialty Hospital and Nursing Facility report that moderate aerobic exercise for 10 weeks, three times a week for 45 minutes each session significantly improved function of the nervous system and circulation in those with HIV disease.

"Cardiovascular and autonomic profiles of the fit HIV+ subjects were significantly improved compared to a similar group that didn't exercise -- regardless if they had HIV or not," lead researcher David K. Spierer said.

"This investigation is the first to explore the profound effects of aerobic fitness on pre-clinical manifestations of cardiovascular and autonomic dysfunction in HIV," Spierer noted. "The takeaway message is that moderate aerobic exercise like biking or using a treadmill in those with HIV may be a cost-effective supplemental therapy, with improved physiological function as the only side-effect," he said.

Spierer worked at the Department of Biobehavioral Sciences, Teachers College, Columbia University with Adrienne Zion, Gregory Gates and Ronald De Meersman and completed the investigation at Coler Goldwater, also in New York City, working with Augusta Alba, Jay Kleinfeld, Eugene McPherson and Julie Romero. *Paper presentation: "Fitness is associated with improved arterial compliance and parasympathetic modulation in HIV," 12:30 p.m.-3 p.m. Sunday April 3, Physiology 347.11/board #A67. On view 7:30 a.m. - 4 p.m.

Spierer is presenting the research at the 35th Congress of the International Union of Physiological Sciences in San Diego, March 31 - April 5, 2005.

Four groups compared for arterial compliance, heart rate, baroreflex sensitivity

The researchers examined the quantitative effects of aerobic fitness on the compliance of the arteries (how flexible the arteries are in allowing adequate blood flow); modulation or alteration of the parasympathetic branch of the autonomic nervous system, which exerts great influence on heart rate, normally elevated in people with HIV; and baroreflex sensitivity, a sensitive reflex in response to blood pressure changes.

These measures were taken in the following four groups: HIV- unfit (HNU), HIV- fit (HNF), HIV+ unfit (HPU), and HIV+ fit (HPF). Groups were matched for age, body mass index, aerobic capacity, and medication. Fit groups participated in a 10-week training program; unfit groups followed their normal daily activities and weren't given a specific exercise program. HIV+ subjects were positive within 24 months of the study, and asymptomatic.

Results both expected and "striking"

Arterial compliance was augmented in HPF vs. HPU (probability, or p=.006). This finding was not surprising. "We expected to see an improved circulation in our HPF group over that of our HPU group. Modulation of the parasympathetic nervous system was higher in HPF vs. HPU (p< .05), meaning that out of those subjects with HIV disease, the exercising group exhibited lower heart rates both at rest and during exercise, compared to the non-exercising group," Spierer reported.

Baroreflex sensitivity was higher for HPF vs. HPU (p=.003) and for HPF vs. HNU (p=.004). "This indicates a greater control of blood pressure in response to external stimuli in those with HIV disease who engaged in moderate aerobic exercise, compared with both those who have HIV but don't exercise, and those without HIV who don't exercise," Spierer said.

"But the most striking result," he added, "was that aerobic conditioning wasn't significantly different between the fit groups, whether or not they had HIV" (41.42.4 vs 43.94.2 ml/kg/minute). Spierer explained: "Those with HIV often suffer from reduced exercise capacity, muscle wasting, and respiratory complications. However, this wasn't the case in the fit HIV+ subjects in our study. In fact, their exercise capacity wasn't significantly different from the fit HIV-negative subjects."

Next steps. The New York researchers plan on doing follow up studies using exercise interventions to determine dose-response and other studies to examine more closely mechanisms of the immune system in response to exercise.

Areas that they'll be studying include: natural killer cell level and activation in response to exercise in HIV disease, circuit training in HIV disease, and various levels of intensity during exercise in those with HIV disease. (Late last year the researchers presented a paper at the American Society of Hemotaology which examined specific changes in immune function in HIV subjects after moderate aerobic exercise.)

The 35th Congress of the International Union of Physiological Sciences is in San Diego, March 31 - April 5, 2005. The Congress (http://www.iups2005.org/) is organized by the six member societies of the U.S. National Committee of the IUPS, the American Physiological Society, the Society for Neuroscience, the Microcirculatory Society, the Society of General Physiologists, the Biomedical Engineering Society, and the Society for Integrative and Comparative Biology, under the auspices of the U.S. National Academy of Sciences.

The IUPS conference, held every four years, runs concurrently this year with Experimental Biology 2005 at the San Diego Convention Center.

The American Physiological Society (APS), which is hosting IUPS, was founded in 1887 to foster basic and applied science, much of it relating to human health. The Bethesda, MD-based Society has more than 10,000 members and publishes nearly 4,000 articles every year in its 14 peer-reviewed journals. In May, APS received the Presidential Award for Excellence in Science, Mathematics and Engineering Mentoring (PAESMEM).

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