(RxWiki News) There have been advances in HIV treatment in recent years, yet nearly half of all people infected with HIV experience life-changing, reduced brain function. New research suggests that exercise could make a big difference for these patients.
A recent study examined the connection between exercise and reduced neurocognitive function in HIV-positive people. Neurocognitive function is the brain's ability to concentrate, remember, process information, learn, speak, understand and reason.
For this study, researchers looked at the effect of exercise on brain function as a whole, as well as on each of those separate areas of brain function.
The researchers found that HIV-positive people who exercised regularly were half as likely to suffer from neurocognitive impairment than the patients who reported no exercise.
The authors concluded that regular exercise might be able to reduce, or even prevent, the development of these impairments.
"Exercise regularly for your body and mind."
This study was conducted through the HIV Neurobehavioral Research Program at the University of California at San Diego. The lead author was David J. Moore, PhD, professor of clinical psychology and researcher within the HIV Neurobehavioral Research Program.
The goal of the study was to look at the association between exercise and neurocognitive impairment in HIV-positive adults. The researchers examined the effects of exercise on neurocognitive functioning of specific areas of the brain, as well as on the brain overall.
The study included 335 HIV-positive adults between the ages of 20 and 79. None of the participants lived in a nursing home or assisted living facility.
The authors evaluated the participants' overall health status from 2007 to 2011 with an initial assessment and then a follow-up.
First, the participants were given a questionnaire asking them to estimate how many minutes they had spent exercising in the previous 72 hours. Exercise was characterized as any physical activity that elevated the heart rate to a higher-than-usual pace.
Then, the authors evaluated the participants' neurocognitive function though a series of tests that measured six specific areas that are typically affected by HIV. The scores from these tests were combined to determine overall neurocognitive impairment.
These areas included verbal fluency (the ability to remember and produce words on a certain subject), working memory (the ability to process and store information as soon as it received), speed of information processing (how quickly an idea is understood), learning and recall (the ability to understand and later remember an idea), executive function (ability to connect past experiences with present actions) and motor function (the ability to use and control muscles and movements).
The authors considered other factors that could have affected the connection between amount of exercise and neurocognitive impairment in the participants. These factors included demographic data (age, gender, education, etc.), specific HIV symptoms, whether or not the participant had hepatitis C, any previous or current substance abuse, general physical functioning, body mass index (weight to height ratio), general mental health status, lifetime or current major depressive disorder diagnosis and current overall mood.
The researchers then divided the participants into an "exercise" group and a "no exercise" group. Eighty-three participants reported exercising within the previous 72 hours, and 252 participants reported no exercise.
The researchers found that the exercise group had lower rates of overall impairment in the brain. Findings also showed that the exercise group was half as likely to suffer from impairment as the no-exercise group, with the exercise group reporting a 16 percent rate of neurocognitive impairment, compared to a 31 percent rate in the no-exercise group.
When the authors looked at the specific areas of neurocognitive function, they found that the exercise group was less impaired when it specifically came to working memory and the speed of information processing.
Of the exercise group, 21 percent were found to have impaired working memory, whereas 40 percent of the no-exercise group reported impairment. When it came to speed of information processing, 24 percent of the exercise group was found to be impaired, compared to 36 percent of the no-exercise group.
The researchers also found that the exercise group reported having more formal education, lower rates of AIDS, fewer major depressive disorders, higher current CD4+ (necessary white blood cells) count and better overall self-reported physical functioning.
The researchers conducted a follow-up analysis in which they took a subgroup of 83 men of similar demographics from both the exercise group and the no-exercise group. They found that the no-exercise subgroup continued to have lower CD4+ counts, higher rates of major depressive disorder and higher instances of AIDS when compared to the exercise group.
One theory that the authors suggest is that exercise may benefit the brain by lowering certain neurocognitive risk factors such as high blood pressure and hyperlipidemia (high levels of fat in the blood). The use of antiretroviral treatment (HIV treatment) is also believed to increase the risk for diabetes, obesity and dyslipidemia (abnormal levels of fats in the blood).
The study highlighted that exercise in general has a huge effect on the brain in terms of stress and general brain activity and thought process.
The authors suggested that the addition of regular exercise to a person's lifestyle has the potential to reduce or even prevent neurocognitive impairment in HIV-positive people.
Overall, the authors stated that these findings agree with an ever-growing body of studies that suggest that exercise has a positive effect on neurocognition — in both HIV-positive and non-infected people.
"Exercise increases oxygen and improves circulation to the brain. It's also known to help the brain generate more brain cells for better cognitive functioning. This will enhance the thought processing ability," Rusty Gregory, a certified strength and conditioning specialist and dailyRx Contributing Expert, told dailyRx News.
The authors noted multiple limitations to their study.
First, exercise was self-reported. The questionnaire was short and did not specify how often or how much exercise was done in various categories.
Second, the authors did not measure exercise over a long period of time. However, they suggested that studies across different areas of function over shorter periods of time may lead participants to self-report more accurately.
Also, the authors believe that the findings possibly reflected the fact that neurocognitive impairment could be an obstacle to exercise. This study did not examine that possibility in detail.
In addition, the authors explained that they could not predict cause and effect accurately from the data because it was an observational study. They believe that an interventional study (in which some of the participants are assigned to a specific exercise intervention while the others are not) is needed to better understand the relationship between exercise and neurocognitive impairment.
Lastly, the authors believe that the differences in demographics and body functionality between the exercise and no-exercise groups might have affected the relationship between exercise and neurocognition. That is why the authors considered other factors in their analysis.
In conclusion, the results suggest that exercise can have a large impact on neurocognitive function in HIV-positive people. However, around half of the population infected with HIV still suffers from neurocognitive impairment. The authors believe that more research is still needed.
This study was published in the August edition of the Journal of NeuroVirology.
Funding for the HIV Neurobehavioral Research Center was provided by an award from the National Institute of Mental Health.