Changes in Soldier Nutritional Status and Immune Function during the RangerTraining Course

摘要

Prompted by several infectious disease epidemics and the perception that weight loss was excessive, the US Army Ranger Training Brigade requested an assessment of the effect of restricted rations on nutritional status, physical performance, and immune function during summer Ranger training. A comprehensive physiological evaluation of 55 volunteers who completed all 4 phases of the 8-1/2 wk course was made at the beginning and end of the course, with abbreviated measurements made at the end of each 2 wk phase. The study revealed that Ranger students have a decreased protection against infection, with decreased T-lymphocyte function. There was no evidence of a vitamin, mineral, or protein deficiency despite reduced rations, and extensive clinical chemistry profiles were remarkably normal, indicating that this is an uncomplicated energy deficiency (average energy expenditure and intake: 4010 and 2800 kcal/day, respectively). Weight loss was high (15.6% of weight) but recovery to original fitness levels occurred by 6 months after the end of training. It is concluded that as little as 300-400 kcal/day increase in intakes may attenuate decrements in physical performance and immune function. A follow-on study of the effects of an intervention using the LLRP ratio is proposed.