Exercise capacity is reported to be reduced in HIV infection, but the cause (s) remains unclear. Highly Active Antiretroviral therapy (HAART) has markedly improved longevity and health status for HIV infected patients, however, these drugs are associated with diverse side-effects which could independently decrease exercise function, including nucleoside reverse transcriptase inhibitor (NRTI) -related mitochondrial toxicity. We hypothesized that patients on HAART with elevated resting blood lactate levels (La, >2.2, EL) would have lower exercise capacity on cardiopulmonary exercise testing, as compared to ART treated patients with normal resting lactate levels (NL), or HIV infected non-ART treated controls (NoH).
Therefore, we compared exercise capacity (as measured by peak oxygen uptake, VO2) in these three groups during cycle ergometry. We studied 29 clinically stable HIV+ infected subjects (27M/2F) without co-morbid conditions which would affect exercise function.
Mean CD4 count for the group was 477 (134, Mean(SD)) cells/mm3 [EL 418 (94), NL 583 (237), NoH 478 (159]. Lean mass was measured by DEXA. Demographics, resting La concentration and Peak VO2 are shown in the table.
Among all three groups peak VO2 and peak VO2/kg were low relative to expected for normal subjects, however, they did not differ significantly with respect to HAART status or resting lactate level.
It appears that reduced exercise capacity is characteristic of HIV infection, regardless of HAART status or resting La values, and could reflect deconditioning or other factors.This study was supported by NIH # R21DK063644 and M01 RR00425.
NAge (y)La (Rest) (mmol)BMI kg/m2PeakVO2 (l/min)Peak VO2/kg (ml/min/kg)Peak VO2/kg (ml/min/lean kg)EL1045 (6)2.58 (.49)*25.3 (3.9)1.73 (0.48)22.8 (5.9)29.6 (6.3)NL946 (3)1.17 (.30)24.8 (2.8)1.69 (0.48)23.5 (7.0)31.4 (7.5)NoH1041 (7)1.51 (.68)24.0 (4.0)1.73 (0.41)25.4 (6.0)32.5 (6.4)*
=P<0.01 for differences between groups
William Stringer, None.