Reduced postexercise recovery oxygen consumptions: an adaptive response in chronic energy deficiency?

Maximal aerobic capacity (VO2max) and oxygen consumption during recovery were measured in well-nourished control subjects (C) and compared with results from chronically energy-deficient (CED) subjects in the same age range. The absolute VO2max was lower in undernourished subjects (2.5 +/- 0.1 L/min [C] v 1.8 +/- 0.1 L/min [CED]; mean +/- SEM, P < .001); however, when expressed per kilogram fat-free mass (FFM), the values were comparable. The total O2 debt was higher in the well-nourished group even when corrected for FFM differences (249.1 +/- 17.1 v 147.3 +/- 9.2 mL/kg FFM; P < .001). O2 consumption in the recovery period returned to baseline values rapidly and in a single phase in undernourished subjects. In contrast, a slow biphasic decline was observed in well-nourished control subjects. The postexercise recovery phase may be an important period during which energy-saving may occur in chronically undernourished human subjects.