The relationship between sleep, pain,and musculoskeletal injuries in US Army Soldiers.

INTRODUCTION: The purpose of this study was to investigate the relationship between sleep and pain in military personnel and to determine if metrics of sleep and pain intensity differ between the injured and uninjured in this population. METHODS: Active-duty US Army Soldiers (n=308; 26.8±6.5 years, 82% male) from the 2nd Infantry Division, Joint Base Lewis-McChord, Washington, and 101st Airborne Division, Fort Campbell, Kentucky, completed the Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), and questionnaires about current musculoskeletal injuries and pain intensity (0=no pain to 10=worst imaginable pain). Pearson correlation coefficients were used to assess the association between pain and sleep. Differences in sleep and pain between injured and uninjured participants were determined using an analysis of covariance. RESULTS: Pain intensity was positively correlated with sleep quality (global PSQI score, r=0.337, p<0.001) and daytime sleepiness (ESS score, r=0.163, p=0.005), and negatively associated with sleep duration (r=-0.118, p=0.039). Injured participants accounted for 37.7% (n=116) of the study population. Injured participants reported greater pain intensity (3.7±2.5 vs 1.3±1.9, p<0.001), were older (28.5±7.4 years vs 25.8±5.7 years, p=0.001) and in the service longer (6.3±6.3 years vs 4.6±4.7 years, p=0.013) than uninjured participants. Injured participants had higher global PSQI scores (9.0±4.1 vs 6.4±3.4, p<0.001), including each of the seven PSQI components (all p<0.050), and reported sleeping less per night than uninjured participants (5.7±1.3 hours vs 6.1±1.2 hours, p=0.026). CONCLUSION: These data demonstrate that pain intensity is associated with sleep in active-duty US Army Soldiers and that those who report a musculoskeletal injury, regardless of age and time in service, report poorer sleep quality, shorter sleep durations, and greater levels of pain than uninjured Soldiers.

Prediction equation for estimating total daily energy requirements of special operations personnel.

BACKGROUND: Special Operations Forces (SOF) engage in a variety of military tasks with many producing high energy expenditures, leading to undesired energy deficits and loss of body mass. Therefore, the ability to accurately estimate daily energy requirements would be useful for accurate logistical planning. PURPOSE: Generate a predictive equation estimating energy requirements of SOF. METHODS: Retrospective analysis of data collected from SOF personnel engaged in 12 different SOF training scenarios. Energy expenditure and total body water were determined using the doubly-labeled water technique. Physical activity level was determined as daily energy expenditure divided by resting metabolic rate. Physical activity level was broken into quartiles (0 = mission prep, 1 = common warrior tasks, 2 = battle drills, 3 = specialized intense activity) to generate a physical activity factor (PAF). Regression analysis was used to construct two predictive equations (Model A; body mass and PAF, Model B; fat-free mass and PAF) estimating daily energy expenditures. RESULTS: Average measured energy expenditure during SOF training was 4468 (range: 3700 to 6300) Kcal·d-1. Regression analysis revealed that physical activity level (r = 0.91; P < 0.05) and body mass (r = 0.28; P < 0.05; Model A), or fat-free mass (FFM; r = 0.32; P < 0.05; Model B) were the factors that most highly predicted energy expenditures. Predictive equations coupling PAF with body mass (Model A) and FFM (Model B), were correlated (r = 0.74 and r = 0.76, respectively) and did not differ [mean ± SEM: Model A; 4463 ± 65 Kcal·d- 1, Model B; 4462 ± 61 Kcal·d- 1] from DLW measured energy expenditures. CONCLUSION: By quantifying and grouping SOF training exercises into activity factors, SOF energy requirements can be predicted with reasonable accuracy and these equations used by dietetic/logistical personnel to plan appropriate feeding regimens to meet SOF nutritional requirements across their mission profile.

Supplementing an energy adequate, higher protein diet with protein does not enhance fat-free mass restoration after short-term severe negative energy balance.

Negative energy balance during military operations can be severe and result in significant reductions in fat-free mass (FFM). Consuming supplemental high-quality protein following such military operations may accelerate restoration of FFM. Body composition (dual-energy X-ray absorptiometry) and whole body protein turnover (single-pool [15N]alanine method) were determined before (PRE) and after 7 days (POST) of severe negative energy balance during military training in 63 male US Marines (means ± SD, 25 ± 3 yr, 84 ± 9 kg). After POST measures were collected, volunteers were randomized to receive higher protein (HIGH: 1,103 kcal/day, 133 g protein/day), moderate protein (MOD: 974 kcal/day, 84 g protein/day), or carbohydrate-based low protein control (CON: 1,042 kcal/day, 7 g protein/day) supplements, in addition to a self-selected, ad libitum diet, for the 27-day intervention (REFED). Measurements were repeated POST-REFED. POST total body mass (TBM; -5.8 ± 1.0 kg, -7.0%), FFM (-3.1 ± 1.6 kg, -4.7%), and net protein balance (-1.7 ± 1.1 g protein·kg-1·day-1) were lower and proteolysis (1.1 ± 1.9 g protein·kg-1·day-1) was higher compared with PRE (P < 0.05). Self-selected, ad libitum dietary intake during REFED was similar between groups (3,507 ± 730 kcal/day, 2.0 ± 0.5 g protein·kg-1·day-1). However, diets differed by protein intake due to supplementation (CON: 2.0 ± 0.4, MOD: 3.2 ± 0.7, and HIGH: 3.5 ± 0.7 g·kg-1·day-1; P < 0.05) but not total energy (4,498 ± 725 kcal/day). All volunteers, independent of group assignment, achieved positive net protein balance (0.4 ± 1.0 g protein·kg-1·day-1) and gained TBM (5.9 ± 1.7 kg, 7.8%) and FFM (3.6 ± 1.8 kg, 5.7%) POST-REFED compared with POST (P < 0.05). Supplementing ad libitum, energy-adequate, higher protein diets with additional protein may not be necessary to restore FFM after short-term severe negative energy balance.NEW & NOTEWORTHY This article demonstrates 1) the majority of physiological decrements incurred during military training (e.g., total and fat-free mass loss), with the exception of net protein balance, resolve and return to pretraining values after 27 days and 2) protein supplementation, in addition to an ad libitum, higher protein (~2.0 g·kg-1·day-1), energy adequate diet, is not necessary to restore fat-free mass following short-term severe negative energy balance.

Whole-body protein turnover response to short-term high-protein diets during weight loss: a randomized controlled trial.

To determine whole-body protein turnover responses to high-protein diets during weight loss, 39 adults (age, 21±1 years; VO2peak, 48±1 ml kg(-1) min(-1); body mass index, 25±1 kg m(2)) were randomized to diets providing protein at the recommend dietary allowance (RDA), 2 × -RDA or 3 × -RDA. A 10-day weight maintenance period preceded a 21-day, 40% energy deficit. Postabsorptive (FASTED) and postprandial (FED) whole-body protein turnover was determined during weight maintenance (day 10) and energy deficit (day 31) using [1-(13)C]leucine. FASTED flux, synthesis and breakdown were lower (P<0.05) for energy deficit than weight maintenance. Protein flux and synthesis were higher (P<0.05) for FED than FASTED. Feeding attenuated (P<0.05) breakdown during weight maintenance but not energy deficit. Oxidation increased (P<0.05) between dietary protein levels and feeding stimulated oxidation, although oxidative responses to feeding were higher (P<0.05) for energy deficit than weight maintenance. FASTED net balance decreased between dietary protein levels, but in the FED state, net balance was lower for 3 × -RDA as compared with RDA and 2 × -RDA (diet-by-state, P<0.05). Consuming dietary protein at levels above the RDA, particularly 3 × -RDA, during short-term weight loss increases protein oxidation with concomitant reductions in net protein balance.