Purpose: The US Marine Corps (USMC) is an elite military organization. Marine recruit training (RT) is a physically and psychologically intense 13-wk-long course designed to transform civilians into Marines through shared hardship and arduous training. Our laboratory conducted a study of female recruits in USMC RT that assessed the nature and the extent of cognitive, nutritional, and physical changes that occur during this unique period of structured mental and physical training.
Methods: During RT, mood state was assessed every 4 wk with a standardized questionnaire, the POMS. Body composition was assessed with dual-energy x-ray absorptiometry every 4 wk, and blood samples were collected for assessing metabolic status at the start and at the completion of training.
Results: At the beginning of RT, approximately 1 wk after arrival at the training facility, levels of several negative mood states assessed by the POMS, depression, anxiety, fatigue, anger, and confusion, were considerably higher than POMS norms for age-matched, female college students. However, over the course of RT, these mood states gradually declined until, by the completion of training, they were substantially lower than college norms. Body composition changed dramatically, with muscle mass increasing by 2.5 +/- 0.2 kg on average and fat declining by 4.7 +/- 0.4 kg. There were also significant changes in several biochemical parameters associated with nutritional and physical status, particularly LDL cholesterol, free fatty acids, and cortisol. Other factors, such as total cholesterol, HDL cholesterol, and glucose, were more stable.
Conclusions: Over the course of USMC RT, mood and body composition improved substantially and dramatically, an indication of the effectiveness of USMC RT for altering the physical and the cognitive status of trainees.