Committee on Military Nutrition Research: Activity Report 1992-1994 (1994)

Conduct a future study of U.S. Ranger Training that begins in winter. This will allow the trainees to be followed through the harshest climate in the mountain phase and provide important comparative data on the role of climatic stressors in the situation, as well as evaluating the higher caloric intake normally provided in winter training.

Develop a protocol to more completely assess recovery from Ranger Training based on the interesting findings from Ranger II. Would dietary recommendations be effective in reducing the excessive post-training weight gain? A detailed food intake study would probably not be cost effective, however, measurements of body composition and body weight at several time points up to one year post-training coupled with limited dietary records would be beneficial.

A small number of people with the most weight loss could be studied after the training course was completed. Perhaps this project could be conducted in a metabolic unit and include muscle biopsies as well as indirect calorimetry to gain additional data during the recovery phase. Such studies possibly could be conducted in collaboration with the Pennington Biomedical Research Center. The project design should focus on individual changes that offer the greatest opportunity to generate data of predictive value for the success of Ranger trainees.

Additional immunological studies would be advantageous in the recovery stage. In particular Killer cell numbers and activities, specific cytokines that influence the acute-phase reaction (IL-1, IL-6, TNF) and B cell function should be measured. (See discussion of question 4 in Part II for additional comments on specific suggestions.)

In a future follow-up study include additional increments of caloric intake and/or sleep to evaluate the degree of the intensity of training that is necessary to achieve the desired outcome. These studies could help answer the question of the degree of stress necessary to achieve the desired training and to measure the effect on completion rate and trainee performance. It would also be important to evaluate the level of increased voluntary activity. Such observations would help determine if activity increases with additional energy intake as seen in Ranger II when compared to Ranger I. This should be considered under the concept of training rigorously but at a level consistent with achieving the desired learning objectives.