Impairment of Exercise Capacity in Various Groups of HIV-lnfected Patients

Abstract

It is known that pulmonary function is impaired during the course of HIV infection even in early stages. In order to estimate the resulting reduction of exercise capacity, different groups of HIV patients were investigated. Group 1 consisted of 20 patients without a history of respiratory disease and without actual lung disease, group 2 of 18 patients with a former episode of Pneumocystis carinii pneumonia (PCP) without actual lung disease, and group III of 37 patients with different broncho-pulmonary complications including PCP 20 normal subjects served as controls. Spirometry, diffusing capacity (DL_CO) and exercise tests including arterial blood gas analysis (BGA) were performed in patients and controls. Compared to the controls group 1 patients revealed a decreased DLco (TCO: 83+15 vs. 67 ± 15%_Pred.norm.) while spirometric data were normal. VO₂ and O₂ pulse at the anaerobic threshold (17.7 ± 5.1 vs. 14.3 ± 2.6 ml/kg min and 10.8 ± 4.0 vs. 8.6 ± 1.9 ml/beat, respectively) and maximum exercise (33.9 ± 9.7 vs. 22.1 ± 3.4 ml/kg min and 15.0 ± 5.0 vs. 11.3 ± 2.5, respectively) were decreased, whereas AaDO₂, V_D/V_T, and the HR/VO2 slope were normal. The reserves of heart rate and ventilation were high. Except for a reduced maximum work rate in group 1, no significant difference was found between groups 1 and 2. Group 3 patients differed most from groups 1 and 2 with respect to spirometry, DLco and AaDO₂, rather than VO₂. VO_2max and maximum work rate correlated with the Walter Reed classification: r = 0.72 (p < 0.0001) and r = 0.78 (p < 0.0001), respectively, suggesting that a more advanced stage of immunodeficiency leads to a decreased exercise capacity. There was also a significant correlation between maximum work rate and the Broca index: r = 0.57 (p < 0.0001).We conclude that an impairment of DLco and exercise capacity is associated with the infection of HIV-1. Analysis of gas exchange patterns suggests that the cause of exercise limitation in groups 1 and 2 is due to anemia and a neuromuscular disorder in the exercising muscles, rather than pulmonary limitations, as were observed in group 3.

Anabolic growth hormone action improves submaximal measures of physical performance in patients with HIV-associated wasting

“…VeT is reduced in conditions characterized by excessive fatigue, including heart failure (12), chronic fatigue syndrome (33), chronic pulmonary disease (45), and acromegaly (60). In this study, VeT was significantly lower than that predicted for healthy sedentary males of similar age, body mass, and stature (18), confirming previous reports of reduced VeT in HIVinfected patients compared with healthy controls (31,47,53).…”

“…Muscle wasting is associated with impaired strength and functional performance (24) and is alleged to be the underlying cause of increased fatigue among such patients. Additionally, diminished aerobic capacity in this patient population is well demonstrated by clinical exercise testing (14,31,32,36,46,47,53). Due to the strong association between HIV-associated muscle wasting and survival, as well as the concomitant diminutions of aerobic capacity and functional status, there has been considerable interest in targeted interventions.…”

Ambulatory Function in Men with and without HIV Infection: Association with Cardiorespiratory Fitness

“…Oxygen utilization at peak exercise (VO2peak) is a gold standard for aerobic exercise capacity and is significantly impaired in HIV-infected adults [15], which is associated with increased age [13], hypertension [16], hyperlactatemia [17], and low CD4 cell count [18]. However, cardiorespiratory testing requires expensive equipment and specially trained staff.…”

HIV - implications for exercise in treatment and rehabilitation

“…Anaemia alone may account for the reduction in VO 2 max noted in some studies (Pothoff et al 1994, Stringer 2000.…”

“…Alveolar arterial oxygen difference was also significantly greater during exercise in group 3. They concluded that HIV infection is associated with impairment of diffusing capacity and exercise capacity and questioned whether the problem was in oxygen delivery or muscle utilisation (Pothoff et al 1994).…”