Caffeine and Performance

The role of caffeine in enhancing performance has been studied for years, and there is no doubt that caffeine can be performance enhancing. Also, a wealth of information allows for an interesting distinction between physical and cognitive performance. Most adults in America consume moderate doses of caffeine in various forms on a daily basis as caffeine is typically found in coffee, tea, soft drinks, dietary supplements, energy drinks, energy shots, and chocolate, as well as over-the-counter pills and gums. Although caffeine is readily available and widely consumed, when using it to enhance performance, a few factors should be considered. The authors discuss caffeine use among Servicemembers, its properties and effects on physical and cognitive performance, how to use it to optimize performance, and, finally, some of safety and regulatory considerations. The bottom line is that all individuals do not respond the same way to caffeine and their response depends on how the body uses and breaks down caffeine. Thus, as a user, you should monitor your own responses and performance changes when using caffeine based on the general recommendations provided.

Pain as a Barrier to Human Performance: A Focus on Function for Self-Reporting Pain With the Defense Veterans Pain Rating Scale

The intense physical demands and dangerous operational environments common to Special Operations Forces (SOF) result in a variety of painful conditions, including musculoskeletal pain, headaches, and acute and chronic pain from combat injuries. Pain is a wellaccepted barrier to human performance. The Pain Management Task Force and the development of the Defense Veterans Pain Rating Scale (DVPRS) are discussed to provide a framework for changing the culture of pain management away from intensity of pain to interference with function and performance. The emergence of complementary and integrative pain management (CIM) practices is briefly reviewed as viable alternatives to the traditional reliance on opioids and other prescription medications. The SOF community can be the change agent for the DVPRS and CIM approaches to pain management, which will in the end serve to accelerate recovery and return SOF operators to duty faster and with an enhanced ability to perform with less pain.

Association of Plasma Heat Shock Protein 70, Interleukin 6, and Creatine Kinase Concentrations in a Healthy, Young Adult Population

Variations of baseline plasma concentrations of creatine kinase (CK), heat shock protein 70 (HSP70), and interleukin 6 (IL-6) have been reported. We report categorical associations which may influence these protein levels. Methods. Blood was harvested for DNA and plasma protein analysis from 567 adults. Mean protein levels of CK, HSP70, and IL-6 were compared by sex, ethnicity, genetic variants-CKMM Nco1 (rs1803285), HSPA1B +A1538G (rs1061581), and IL6 G-174C (rs1800795)-self-reported history of exercise, oral contraceptive use, and dietary supplement use. Results. SNP major allele frequencies for CKMM, HSPA1B, and IL6 were 70% A, 57% A, and 60%. Mean CK statistically differed by sex, ethnicity, oral contraceptives, and caffeine. Plasma HSP70 differed by caffeine and protein. Mean IL-6 concentration differed by sex, ethnicity, and genotype. Plasma IL-6 was significantly lower (29%) in males (1.92 ± 0.08 pg/mL) and higher (29%) among African Americans (2.85 ± 0.50 pg/mL) relative to the others. IL6 G-174C GG genotype (2.23 ± 0.14 pg/mL) was 19% greater than CG or CC genotypes. Conclusion. Differences in baseline CK and IL-6 plasma protein concentrations are associated with genetics, sex, ethnicity, and the use of oral contraceptives, caffeine, and protein supplements in this young and athletic population.

Trends in B-Vitamin Prescriptions From Military Treatment Facilities: 2007 to 2011

INTRODUCTION

The use of B-vitamin supplements has increased over the last decade. Although use is widespread in both military and civilian populations, data on patterns of B-vitamin prescription rates are lacking.

OBJECTIVE

This study examines trends in B-vitamin prescriptions dispensed by military treatment facilities.

METHODS

We examined data from the Department of Defense Pharmacy Data Transaction Service to determine the nature of several B-vitamin prescriptions dispensed through military treatment facilities from 2007 through 2011. The eight B vitamins examined were B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (panthenol), B6 (pyridoxine), B7 (biotin), B9 (folic acid), and B12 (cobalamin).

RESULTS

The number of B-vitamin prescriptions dispensed from military treatment facilities decreased 7% from 278,972 in 2007 to 260,472 in 2011. Individual vitamin prescription patterns varied widely. Vitamins B6, B9, and B12 were the most frequently prescribed in each year. Vitamin B2 prescriptions quadrupled between 2009 and 2011, and B12 prescriptions showed a steady increase over time. In contrast, vitamins B3, B6, and B9 prescriptions showed a steady decline, and vitamin B7 prescriptions decreased by 66% between 2008 and 2009.

CONCLUSIONS

No single pattern in B-vitamin prescriptions was observed. The driving forces behind increases in prescribed and non-prescribed dietary supplement use remain speculative.

Third-Party Evaluation: A Review of Dietary Supplements Dispensed by Military Treatment Facilities From 2007 to 2011

INTRODUCTION

Third-party certification/verification of dietary supplements (DS), although not mainstream, is one way to help ensure high-quality products. In the medical setting, physicians may prescribe DS to correct a deficiency or improve a health care outcome, and they want products of a certain standard of quality, free of adulteration/contamination.

OBJECTIVE

We reviewed DS dispensed from all Department of Defense military treatment facilities over a 5-year period to determine which products had been third-party reviewed and certified/verified.

METHODS

By using product name, manufacturer, and/or National Drug Codes, we examined product listings on the websites of three independent-evaluating organizations.

RESULTS

Over 1.5 million dietary supplement prescriptions consisting of 753 different products were dispensed from 2007 through 2011. Less than 3.6% of the products examined were third-party certified/verified by any of the three most well-known evaluation organizations: 19 were verified by United States Pharmacopeial Convention; 9 products were reviewed and 8 certified by ConsumerLab; and none of the products were certified by NSF International.

CONCLUSION

Most DS dispensed by military treatment facilities are not reviewed by a third party. This is not unexpected, as third party certification is not yet mainstream. However, one way to reduce potential hazards and exposure to unsafe products is to encourage use of supplements that have third-party certification/verification.

Executive summary of NIH workshop on the Use and Biology of Energy Drinks: Current Knowledge and Critical Gaps

Sales of energy drinks in the United States reached $12.5 billion in 2012. Emergency department visits related to consumption of these products have increased sharply, and while these numbers remain small relative to product sales, they raise important questions regarding biological and behavioral effects. Although some common ingredients of energy drinks have been extensively studied (e.g., caffeine, B vitamins, sugars, inositol), data on other ingredients (e.g., taurine) are limited. Summarized here are data presented elsewhere in this issue on the prevalence and patterns of caffeine-containing energy drink use, the effects of these products on alertness, fatigue, cognitive functions, sleep, mood, homeostasis, as well as on exercise physiology and metabolism, and the biological mechanisms mediating the observed effects. There are substantial data on the effects of some energy drink ingredients, such as caffeine and sugars, on many of these outcomes; however, even for these ingredients many controversies and gaps remain, and data on other ingredients in caffeine-containing energy drinks, and on ingredient interactions, are sparse. This summary concludes with a discussion of critical gaps in the data and potential next steps.

Effects of omega-3 fatty acid supplementation on neurocognitive functioning and mood in deployed U.S. soldiers: a pilot study

Omega-3 fatty acids (FAs) may have neuroprotective properties for psychological health and cognition. The objective of this study was to evaluate the effectiveness of omega-3 FAs (eicosapentaenoic + docosahexaenoic; Harris-Schacky [HS]-Omega-3 Index) on neuropsychological functioning among U.S. Soldiers deployed to Iraq. This randomized, double-blind, placebo-controlled trial included Soldiers between the ages of 18 and 55 years who were randomly assigned to either the active treatment group (n = 44) or placebo group (n = 34). Active treatment was 2.5 g per day of eicosapentaenoic + docosahexaenoic (Lovaza; GlaxoSmithKline, Research Triangle Park, North Carolina). The placebo was corn oil ethyl esters. HS-Omega-3 Index, a neurocognitive battery (Central Nervous System-Vital Signs, Morrisville, North Carolina), and psychological health scales were assessed at baseline and after 60 days of treatment. Although the results revealed that omega-3 FAs significantly increased the HS-Omega-3 Index (p = 0.001), there were no significant effects on indices psychological health and neurocognitive functioning by treatment group. Nevertheless, there was a significant inverse correlation between the changes in the HS-Omega-3 Index and daytime sleepiness (r = 0.30, p = 0.009). Short-term treatment with 2.5 g of omega-3 FAs did not alter measures of neurocognition or psychological health, but there was evidence of a relationship between omega-3 levels and daytime sleepiness.

Physical fitness and injury reporting among active duty and National Guard/Reserve women: associations with risk and lifestyle factors

OBJECTIVE

As more women enter the military, it is important to understand how different risks and lifestyle factors influence physical fitness and injury among women in both active duty (AD) and National Guard/Reserve (NG/R). Women in military service are less fit and more likely to suffer musculoskeletal injuries during physical training than men. They also use more medical care during deployment than men. Using data from the Comprehensive Soldier and Family Fitness Global Assessment Tool 2.0 (GAT 2.0), self-reported health and lifestyle and behavioral risk factors were analyzed in nondeployed Army personnel, with the goals of examining (1) service-component differences across traditional risk and lifestyle factors, and (2) correlates of physical performance and physical activity-related injury.

METHODS

Self-report GAT 2.0 data included health risk factors (overall perceived health, sleep, diet, tobacco and alcohol use), self-reported health metrics (height, weight, Army Physical Fitness Test (APFT) scores), and history of physical activity-related injury. The GAT 2.0 was completed by 1,322 AD and 1,033 NG/R women, and APFT data were available for a subsample of 605 AD and 582 NG/R women.

RESULTS

Initial analyses of GAT 2.0 data indicated that AD had higher rates of fair/poor perceived health, poor sleep, and unhealthy diet compared to NG/R women. However, AD women had a lower APFT fail rate (8%) than NG (27%) and R (28%). Active duty women were more likely to experience a physical injury in the past 6 months (38%) than NG (19%) and R (22%) women, and more likely to seek medical care than NG/R women. Across all service components, predictive factors for APFT failure included high body mass index (BMI), fair/poor health, and unhealthy diet. Predictive factors for physical injury included high BMI, fair/poor health, and binge drinking.

CONCLUSION

Our analyses suggest that AD women Soldiers are more physically fit than NG/R women Soldiers, which is accompanied by a greater prevalence of physical activity-related injuries. As women's roles expand into combat military occupation specialties, a thorough understanding of service component differences will be critical to inform training programs, mitigate physical injury, and enhance force health protection and readiness.

Women and exertional heat illness: identification of gender specific risk factors

OBJECTIVE

With the expanding role of women into previously closed combat military occupational specialties, women will likely be exposed more to challenging and extreme conditions. Physical work or exercise in extreme environments could increase the risk for exertional heat illness (EHI) and exertional heat stroke (EHS), the most severe type of EHI. Although men have higher rates of EHS than women, women have slightly higher rates of other EHI. Women may respond differently to exertion in the heat than men, as they typically have higher percentage of body fat (BF%) and lower aerobic power. Further, published pilot-data using the Israeli heat tolerance test (HTT) indicate that women are more likely to be classified as heat intolerant than men. The objectives of the present study were to (1) compare male and female classification patterns of heat tolerance, and (2) identify EHI risk factors that might account for the relationship between heat tolerance classification and sex.

METHODS

Fifty-five male and 20 female participants were recruited from military and university communities to participate in a standardized HTT. Subjects underwent measures to calculate anthropometric variables (BF%, body surface area, and waist circumference), a maximal oxygen uptake test to assess aerobic power (VO₂max), and a standardized HTT, which consisted of treadmill walking at 5 km/h at a 2% grade for 120 minutes at 40°C and 40% relative humidity. Heat intolerance was defined as attaining a maximum heart rate (HR) greater than 150 bpm or a core body temperature (Tc) more than 38.5°C. Separate hierarchical regressions were conducted using categorical (heat tolerant/intolerant) and continuous (physiological strain index, maximum HR, Tc) HTT outcomes. Risk factors were identified with and without controlling for sex.

RESULTS

Women were 3.7 (95% CI, 1.21-11.24) times more likely to be heat intolerant than men (χ²=6.85, P<.01). Compared to men, women had significantly higher BF% and lower body surface area, waist circumference, and VO₂max. All heat intolerant participants had lower VO₂max and higher BF% than those who were classified as heat tolerant. When VO₂max and BF% were entered into regression equations to predict HTT outcomes, sex became nonsignificant; VO₂max predicted maximum HR and physiological strain index after controlling for sex.

CONCLUSION

The present study found that differences between men and women in heat tolerance classification are largely explained by VO₂max. The higher rates of heat intolerance among women likely correlate with higher EHI risk, and underscore the need to understand the physiological and thermoregulatory differences between men and women. As lower aerobic power is a major risk factor for EHI, maximizing the aerobic power of women will be critical to force health protection and readiness as they integrate into combat military occupational specialties.

US Military Dietary Protein Recommendations: A Simple But Often Confused Topic

Military recommendations for dietary protein are based on the recommended dietary allowance (RDA) of 0.8 g of protein per kilogram of body mass (BM) established by the Food and Nutrition Board, Institute of Medicine (IOM) of the National Academies. The RDA is likely adequate for most military personnel, particularly when activity levels are low and energy intake is sufficient to maintain a healthy body weight. However, military recommendations account for periods of increased metabolic demand during training and real-world operations, especially those that produce an energy deficit. Under those conditions, protein requirements are higher (1.5-2.0 g/kg BM) in an attempt to attenuate the unavoidable loss of muscle mass that occurs during prolonged or repeated exposure to energy deficits. Whole foods are recommended as the primary method to consume more protein, although there are likely operational scenarios where whole foods are not available and consuming supplemental protein at effective, not excessive, doses (20-25 g or 0.25-0.3 g/kg BM per meal) is recommended. Despite these evidence-based, condition-specific recommendations, the necessity of protein supplements and the requirements and rationale for consuming higher-protein diets are often misunderstood, resulting in an overconsumption of dietary protein and unsubstantiated health-related concerns. This review will provide the basis of the US military dietary protein requirements and highlight common misconceptions associated with the amount and safety of protein in military diets.

Androgens and Androgen Derivatives: Science, Myths, and Theories: Explored From a Special Operations Perspective

Androgen use outside of legitimate medical therapy is a perceived concern that is drawing attention across military and specifically Special Operations Forces (SOF) communities. For leadership and the medical community to properly address the issue and relate to those individuals who are using or considering use, it will be crucial to understand the scope of the problem. Limited data suggest that the prevalence of androgen use may be increasing, and inferences made from the scientific literature suggest that SOF may be a population of concern. While risks of androgen use are well known, there are little data specific to military performance that can be applied to a rigorous risk:benefit analysis, allowing myths and poorly supported theories to perpetuate within the community. Further efforts to define the potential benefits balanced against the short- and long-term risks should be undertaken. Providers within the SOF community should arm themselves with information to engage androgen users and leadership in meaningful discussion regarding androgen use.

Mindfulness: a fundamental skill for performance sustainment and enhancement

The term "mindfulness" has become very fashionable within the military and across multiple sectors of civilian and first responder populations. Overall, the key concept of mindfulness is intentionally being acutely aware of what is going on internally as well as externally, without reacting. Mindfulness and the awareness that underlies it are inherent capabilities that can be honed through training. As such, classes in mindfulness are being offered in many venues and medical clinics are using mindfulness-based interventions for patients for a wide range of medical issues. The evidence behind the benefits of mindfulness is extensive and instructive. Importantly, evidence suggests that mindfulness can be helpful for many operational, leadership, and personal activities and is likely beneficial for enhancing resilience and overall health. Many current military leaders are using mindfulness as a tool to better prepare for a dynamic and uncertain future.

Factor structure of the functional movement screen in marine officer candidates

Functional movement screening (FMS) is a musculoskeletal assessment that is intended to fill a gap between preparticipation examinations and performance tests. Functional movement screening consists of 7 standardized movements involving multiple muscle groups that are rated 0-3 during performance; scores are combined into a final score, which is intended to predict injury risk. This use of a sum-score in this manner assumes that the items are unidimensional and scores are internally consistent, which are measures of internal reliability. Despite research into the FMS' predictive value and interrater reliability, research has not assessed its psychometric properties. The present study is a standard psychometric analysis of the FMS and is the first to assess the internal consistency and factor structure of the FMS, using Cronbach's alpha and exploratory factor analysis (EFA). Using a cohort of 877 male and 57 female Marine officer candidates who performed the FMS, EFA of polychoric correlations with varimax rotation was conducted to explore the structure of the FMS. Tests were repeated on the original scores, which integrated feelings of pain during movement (0-3), and then on scores discounting the pain instruction and based only on the performance (1-3), to determine whether pain ratings affected the factor structure. The average FMS score was 16.7 ± 1.8. Cronbach's alpha was 0.39. Exploratory factor analysis availed 2 components accounting for 21 and 17% and consisting of separate individual movements (shoulder mobility and deep squat, respectively). Analysis on scores discounting pain showed similar results. The factor structures were not interpretable, and the low Cronbach's alpha suggests a lack of internal consistency in FMS sum scores. Results do not offer support for validity of the FMS sum score as a unidimensional construct. In the absence of additional psychometric research, caution is warranted when using the FMS sum score.

The effectiveness of melatonin for promoting healthy sleep: a rapid evidence assessment of the literature

A systematic review was conducted using Samueli Institute’s Rapid Evidence Assessment of the Literature (REAL^©) process to determine the evidence base for melatonin as an agent to optimize sleep or improve sleep quality, and generalize the results to a military, civilian, or other healthy, active, adult population. Multiple databases were searched yielding 35 randomized controlled trials (RCTs) meeting the review’s inclusion criteria, which were assessed for methodological quality as well as for melatonin effectiveness. The majority of included studies were high quality (83.0%). Overall, according to Grading Recommendations, Assessment Development and Evaluation (GRADE) methodology, weak recommendations were made for preventing phase shifts from jet lag, for improving insomnia in both healthy volunteers and individuals with a history of insomnia, and for initiating sleep and/or improving sleep efficacy. Based on the literature to date, no recommendations for use in shift workers or to improve hormonal phase shift changes in healthy people can be made at this time. Larger and longer-duration RCTs utilizing well characterized products are needed to warrant melatonin recommendations in young, healthy adults.

Biological mechanisms underlying the role of physical fitness in health and resilience

Physical fitness, achieved through regular exercise and/or spontaneous physical activity, confers resilience by inducing positive psychological and physiological benefits, blunting stress reactivity, protecting against potentially adverse behavioural and metabolic consequences of stressful events and preventing many chronic diseases. In this review, we discuss the biological mechanisms underlying the beneficial effects of physical fitness on mental and physical health. Physical fitness appears to buffer against stress-related disease owing to its blunting/optimizing effects on hormonal stress responsive systems, such as the hypothalamic-pituitary-adrenal axis and the sympathetic nervous system. This blunting appears to contribute to reduced emotional, physiological and metabolic reactivity as well as increased positive mood and well-being. Another mechanism whereby regular exercise and/or physical fitness may confer resilience is through minimizing excessive inflammation. Chronic psychological stress, physical inactivity and abdominal adiposity have been associated with persistent, systemic, low-grade inflammation and exert adverse effects on mental and physical health. The anti-inflammatory effects of regular exercise/activity can promote behavioural and metabolic resilience, and protect against various chronic diseases associated with systemic inflammation. Moreover, exercise may benefit the brain by enhancing growth factor expression and neural plasticity, thereby contributing to improved mood and cognition. In summary, the mechanisms whereby physical fitness promotes increased resilience and well-being and positive psychological and physical health are diverse and complex.