Fatigue in Persian Gulf Syndrome - Physiologic Mechanisms

摘要

We investigated the basis of symptoms of exertional fatigue in 30 symptomatic and 21 asymptomatic Gulf War (GW)Veterans matched for age, height and weight. Serum OK, incidence of elevated OK, and muscle histology and fatigue rate and level of oxygen uptake relative to 02 delivery during forearm exercise were similar in both groups. In contrast, peak cycle work (126 +/-34 versus 153 +/-43 watts), oxygen utilization (23.5 +/-5.5 vs 27.4 +/-7.4 ml.kg sub 1 min sub 1), and cardiac output (173 +/- 53 3153 vs 2061 49.kg sub -1 min sub -1), and peak blood lactate (6.612.3 vs 8.0 +/-2.3 mM) and potassium (5.5 +/-0.6 vs 6.0 +/-0.7 mM) were lower (p<.05) in symptomatic veterans. Mean resting heart rate was higher and peak exercise heart rate and activities of oxidative enzymes were lower in symptomatic veterans but these differences were not statistically significant. In response to 10 weeks of regular cycle exercise, a cohort of symptomatic veterans (n=7) showed a normal increase in work capacity (139 +/-24 watts pre, 166 +/-25 watts post training, p<.OOl) and in oxidative capacity (peak 02 uptake pre 25.4 +/-3.5 ml kg sub -1 min sub -1 , post 29.2 +/-4). Our results indicate that lower oxidative capacity attributable to lower levels of cardiovascular fitness correlate with symptoms of fatigability in Gulf War veterans and can be reversed by exercise training.