Soldiers, like civilians, use large amounts of DSs, often in combination. Soldiers use more DSs purported to enhance performance than civilians use when matched for key demographic factors. These differences may reflect the unique occupational demands and stressors of military service.

Physiological consequences of winter military operations are not well described. This study examined Norwegian soldiers (n = 21 males) participating in a physically demanding winter training program to evaluate whether short-term military training alters energy and whole-body protein balance, muscle damage, soreness, and performance. Energy expenditure (D2(18)O) and intake were measured daily, and postabsorptive whole-body protein turnover ([(15)N]-glycine), muscle damage, soreness, and performance (vertical jump) were assessed at baseline, following a 4-day, military task training phase (MTT) and after a 3-day, 54-km ski march (SKI). Energy intake (kcal·day(-1)) increased (P < 0.01) from (mean ± SD (95% confidence interval)) 3098 ± 236 (2985, 3212) during MTT to 3461 ± 586 (3178, 3743) during SKI, while protein (g·kg(-1)·day(-1)) intake remained constant (MTT, 1.59 ± 0.33 (1.51, 1.66); and SKI, 1.71 ± 0.55 (1.58, 1.85)). Energy expenditure increased (P < 0.05) during SKI (6851 ± 562 (6580, 7122)) compared with MTT (5480 ± 389 (5293, 5668)) and exceeded energy intake. Protein flux, synthesis, and breakdown were all increased (P < 0.05) 24%, 18%, and 27%, respectively, during SKI compared with baseline and MTT. Whole-body protein balance was lower (P < 0.05) during SKI (-1.41 ± 1.11 (-1.98, -0.84) g·kg(-1)·10 h) than MTT and baseline. Muscle damage and soreness increased and performance decreased progressively (P < 0.05). The physiological consequences observed during short-term winter military training provide the basis for future studies to evaluate nutritional strategies that attenuate protein loss and sustain performance during severe energy deficits.

This study examined demographic and physical risk factors for stress fractures in a large cohort of basic trainees. New recruits participating in US Army BCT from 1997 through 2007 were identified, and birth year, race/ethnicity, physical characteristics, body mass index, and injuries were obtained from electronic databases. Injury cases were recruits medically diagnosed with inpatient or outpatient stress fractures. There were 475 745 men and 107 906 women. Stress fractures incidences were 19.3 and 79.9 cases/1 000 recruits for men and women, respectively. Factors that increased stress fracture risk for both men and women included older age, lower body weight, lower BMI, and race/ethnicity other than black. Compared to Asians, those of white race/ethnicity were at higher stress fractures risk. In addition, men, but not women, who were taller or heavier were at increased stress fracture risk. Stress fracture risk generally increased with age (17-35 year range) at a rate of 2.2 and 3.9 cases/1 000 recruits per year for men and women, respectively. This was the largest sample of military recruits ever examined for stress fractures and found that stress fracture risk was elevated among recruits who were female, older, had lower body weight, had lower BMI, and/or were not of black race/ethnicity.

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Data from the National Health and Nutrition Examination Survey (NHANES) indicate 89% of Americans regularly consume caffeine, but these data do not include military personnel. This cross-sectional study examined caffeine use in Navy and Marine Corps personnel, including prevalence, amount of daily consumption, and factors associated with use. A random sample of Navy and Marine Corps personnel was contacted and asked to complete a detailed questionnaire describing their use of caffeine-containing substances, in addition to their demographic, military, and lifestyle characteristics. A total of 1708 service members (SMs) completed the questionnaire. Overall, 87% reported using caffeinated beverages ≥1 time/week, with caffeine users consuming a mean ± standard error of 226 ± 5 mg/day (242 ± 7 mg/day for men, 183 ± 8 mg/day for women). The most commonly consumed caffeinated beverages (% users) were coffee (65%), colas (54%), teas (40%), and energy drinks (28%). Multivariable logistic regression modeling indicated that characteristics independently associated with caffeine use (≥1 time/week) included older age, white race/ethnicity, higher alcohol consumption, and participating in less resistance training. Prevalence of caffeine use in these SMs was similar to that reported in civilian investigations, but daily consumption (mg/day) was higher.

Like Army personnel, college students and athletes, USAF personnel use more DS than the general population and are more likely to use purported performance enhancing DS, such as protein supplements, and concurrently consume multiple DS. Austin KG, Price LL, McGraw SM, Leahy G, Lieberman HR. Demographic, lifestyle factors, and reasons for use of dietary supplements by Air Force personnel. Aerosp Med Hum Perform. 2016; 87(7):628-637.

Data from the National Health and Nutrition Examination Survey (NHANES) indicated that 89% of Americans regularly consumed caffeinated products, but these data did not include military personnel. This cross-sectional study examined caffeine consumption prevalence, amount of daily consumption, and factors associated with caffeine intake in active duty United States (US) Air Force personnel. Service members (N = 1787) stationed in the US and overseas completed a detailed questionnaire describing their intake of caffeine-containing products in addition to their demographic, lifestyle, and military characteristics. Overall, 84% reported consuming caffeinated products ≥1 time/week with caffeine consumers ingesting a mean ± standard error of 212 ± 9 mg/day (224 ± 11 mg/day for men, 180 ± 12 mg/day for women). The most commonly consumed caffeinated products (% users) were sodas (56%), coffee (45%), teas (36%), and energy drinks (27%). Multivariate logistic regression modeling indicated that characteristics independently associated with caffeine consumption (≥1 time/week) included older age, ethnicity other than black, tobacco use, less aerobic training, and less sleep; energy drink use was associated with male gender, younger age, tobacco use, and less sleep. Compared to NHANES data, the prevalence of caffeine consumption in Air Force personnel was similar but daily consumption (mg/day) was higher.