Physical Fitness in Children Infected with the Human Immunodeficiency Virus: Associations with Highly Active Antiretroviral Therapy

Obesity, sedentary lifestyles, and antiretroviral therapies may predispose HIV-infected children to poor physical fitness. Estimated peak oxygen consumption (VO2 peak), maximal strength and endurance, and flexibility were measured in HIV-infected and uninfected children. Among HIV-infected children, anthropometric and HIV disease-specific factors were evaluated to determine their association with VO2 peak. Forty-five HIV-infected children (mean age 16.1 years) and 36 uninfected children (mean age 13.5 years) participated in the study. In HIV-infected subjects, median viral load was 980 copies/ml (IQR 200-11,000 copies/ml), CD4% was 28% (IQR 15-35%), and 82% were on highly active antiretroviral therapy (HAART). Compared to uninfected children, after adjusting for age, sex, race, body fat, and siblingship, HIV-infected children had lower VO2 peak (25.92 vs. 30.90 ml/kg/min, p < 0.0001), flexibility (23.71% vs. 46.09%, p = 0.0003), and lower-extremity strength-to-weight ratio (0.79 vs. 1.10 kg lifted/kg of body weight, p = 0.002). Among the HIV-infected children, a multivariable analysis adjusting for age, sex, race, percent body fat, and viral load showed VO2 peak was 0.30 ml/kg/min lower per unit increase in percent body fat (p < 0.0001) and VO2 peak (SE) decreased 29.45 (+/-1.62), 28.70 (+/-1.87), and 24.09 (+/-0.75) ml/kg/min across HAART exposure categories of no exposure, < 60, and >= 60 months, respectively (p < 0.0001). HIV-infected children had, in general, lower measures of fitness compared to uninfected children. Factors negatively associated with VO2 peak in HIV-infected children include higher body fat and duration of HAART >= 60 months. Future studies that elucidate the understanding of these differences and mechanisms of decreased physical fitness should be pursued.