HIV and its therapies and complications can lead to muscle wasting, loss of bone mineral density, and metabolic complications. HIV-infected populations suffer from impaired aerobic capacity, decreased maximum oxygen consumption, decreased flexibility, decreased muscular strength, insulin resistance, and lipodystrophy, which may be a result of the disease, therapies, or a combination of both [68
]. Exercise can be coupled with pharmacological treatment and nutritional counseling to alleviate some of the symptoms associated with HIV infection. There have been a number of earlier, non-controlled studies that show resistance and aerobic training improve body composition, strength, and fitness and are well tolerated in the HIV population [94
]. In a randomized, controlled study of 27 HIV-infected adults, Farinatti confirmed that an aerobic, resistance, and flexibility exercise program in HIV-infected adults on HAART can increase muscular strength and reduce heart rate without any negative effects on immune function [99
]. However, they did not evaluate metabolic outcomes in this study. Evaluating the effects of physical activity on metabolic outcomes is critical because of ongoing risks based on chronic ART exposures and viral infection. Randomized, controlled trials are even more limited.
There are now a few reports on the benefits of physical activity on metabolic outcomes in HIV. In a systematic review of randomized controlled trials, Fillipas reported that aerobic exercise decreases total body fat and improves lipid profiles in HIV-infected individuals [100
]. In a recent randomized clinical trial in HIV-infected adults, a one-hour, three times weekly supervised gym class with monthly nutritional counseling was compared to a monthly workshop to discuss the importance of physical activity and nutrition [101
]. All quality of life domains, except pain, were improved in both the intervention and control group but general health, vitality, and mental health were significantly higher for the exercise group. The exercise group also had significant improvements in lean mass, resting heart rate, hip circumference, CD4 cell count, metabolic equivalents, glucose levels, and maximum oxygen consumption. In addition, total cholesterol levels that were above the limits of the National Cholesterol Education Program III before the intervention, decreased to within normal limits after 6 months of the exercise intervention. This is one of the largest randomized controlled trials on exercise in HIV-infected patients and one of the first in this population to show improvements in metabolic outcomes with exercise. In another randomized controlled study of participants with insulin resistance and central adiposity, the implementation of a four-month exercise training program consisting of 1.5 to 2 hours of aerobic and resistance exercise three times a week augmented the insulin-sensitizing benefits of pioglitazone and the intervention with exercise was associated with a decrease in both trunk and limb fat [102
]. Although the effect of pioglitazone and exercise in combination is promising, the investigators did not study the effects of exercise alone. These findings indicate that an exercise program can be effective in improving the health outcomes of patients with HIV undergoing ART to reduce the risk of diabetes and hyperlipidemia.
Although the number of children with perinatally-acquired HIV is decreasing in developed nations, they continue to represent a significant number of HIV-infected patients world-wide [103
]. Studies on physical activity in this group are limited. A single-arm feasibility and effectiveness study that evaluated a 3-month structured exercise program combined with a 3-month home based program among HIV-infected children found, similarly, that a combination resistance and aerobic activity administered twice weekly increases muscle endurance, cardiorespiratory fitness, and lean body mass [104
]. No changes in metabolic outcomes were appreciated, although the sample size was small. Baseline aerobic capacity among HIV-infected children is lower than controls and this decrease in aerobic capacity is related to increased body fat and longer receipt of HAART [93
]. No randomized exercise trials in children have been published.
On the other end of the life spectrum, physical activity can help with the age-associated declines in bone mineral density and CD4 counts among HIV-infected individuals [105
]. The implementation of a moderate to vigorous aerobic and resistance exercise program 3 times per week can improve cardiovascular, metabolic, and muscle function in older individuals living with HIV [107
]. A one-year biweekly resistance exercise program in HIV-infected individuals over the age of 60 years found that exercise improves muscular strength, glucose levels, and lipids [108
]. Although the study was not randomized, it was prospective and controlled. In the control group of participants not living with HIV, the rate of increase of muscular strength was greatest in the first six months while the HIV-infected individuals showed a linear rate of increase indicating that the training program should be continued for more than one year to achieve maximal benefits.
Alternative physical activity interventions are also being studied. A recent study by Cade found that in a randomized controlled trial, yoga is effective at reducing systolic and diastolic blood pressure [109
]. HIV-infected adults on ART participated in one-hour yoga sessions 2-3 times per week aimed to encourage adherence, self-control, mental focus, self-awareness and physical resilience. This study has important implications on its effects on blood pressure, but there were no changes in body composition or metabolic parameters. Since, yoga is a low cost, non-invasive, and widely available intervention, its effects on blood pressure reduction may contribute to decreasing the risk of CVD.
In addition to the potential benefits of improving metabolic and body composition outcomes, physical activity may have added value in helping fatigue, depression, and anxiety – pervasive symptoms among HIV-infected patients [110
]. In a recent review article, Jong and colleagues found that exercise is an effective way to reduce HIV-related fatigue, depression, and anxiety and improve quality of life [111
One of the major limitations of exercise programs in controlling HIV-related symptoms is the poor compliance among participants. Petroczi found that about 55% of patients adhere to an exercise program and perceived well-being is highly associated with adherence [112
]. Thus behavioral interventions can potentially serve to increase compliance with physical activity and diet recommendations. El-Bassel suggests that a multiple-behavior intervention is more effective than a single-behavior intervention to achieve the desired changes in physical activity and diet [113
]. Rotheram-Borus suggests using a family based intervention for the treatment of HIV-related complications [114
]. A cognitive–behavioral stress management training combined with expressive–supportive therapy helped to improve health behaviors (high levels of medication adherence, appropriate nutritional intake and physical activity, safer sexual practices, and reduced alcohol use/abuse) among minority and underserved HIV-infected women [115
]. Future studies are needed to investigate other methods of improving adherence.
The evidence for the benefits of regular physical activity for people living with HIV is limited but persuasive. Exercise augments fitness, metabolic endpoints, quality of life and overall function for those who are compliant with an exercise program. However, adherence to a regular fitness program is a major challenge for many, and strategies to engage patients in physical activity are needed. Specialized equipment to assist the individual track progress, or programs delivered in the community, work or school-setting are approaches that may help [95
]. summarizes novel strategies aimed at delivering or measuring the compliance to physical activity. All programs should target the current recommendations of 30 minutes a day, 5 days per week of moderate to vigorous physical activity [121
Potential Strategies to Increase Physical Activity Among Individuals with HIV Infection that are Effective in Other Populations