Relationship between combat-related traumatic injury and ultrashort term heart rate variability in a UK military cohort: findings from the ADVANCE study.

INTRODUCTION: Combat-related traumatic injury (CRTI) has been linked to an increased cardiovascular disease (CVD) risk. The long-term impact of CRTI on heart rate variability (HRV)-a robust CVD risk marker-has not been explored. This study investigated the relationship between CRTI, the mechanism of injury and injury severity on HRV. METHODS: This was an analysis of baseline data from the ArmeD SerVices TrAuma and RehabilitatioN OutComE (ADVANCE) prospective cohort study. The sample consisted of UK servicemen with CRTI sustained during deployment (Afghanistan, 2003-2014) and an uninjured comparison group who were frequency matched to the injured group based on age, rank, deployment period and role in theatre. Root mean square of successive differences (RMSSD) was measured as a measure of ultrashort term HRV via <16 s continuous recording of the femoral arterial pulse waveform signal (Vicorder). Other measures included injury severity (New Injury Severity Scores (NISS)) and injury mechanism. RESULTS: Overall, 862 participants aged 33.9±5.4 years were included, of whom 428 (49.6%) were injured and 434 (50.3%) were uninjured. The mean time from injury/deployment to assessment was 7.91±2.05 years. The median (IQR) NISS for those injured was 12 (6-27) with blast being the predominant injury mechanism (76.8%). The median (IQR) RMSSD was significantly lower in the injured versus the uninjured (39.47 ms (27.77-59.77) vs 46.22 ms (31.14-67.84), p<0.001). Using multiple linear regression (adjusting for age, rank, ethnicity and time from injury), geometric mean ratio (GMR) was reported. CRTI was associated with a 13% lower RMSSD versus the uninjured group (GMR 0.87, 95% CI 0.80-0.94, p<0.001). A higher injury severity (NISS ≥25) (GMR 0.78, 95% CI 0.69-0.89, p<0.001) and blast injury (GMR 0.86, 95% CI 0.79-0.93, p<0.001) were also independently associated with lower RMSSD. CONCLUSION: These results suggest an inverse association between CRTI, higher severity and blast injury with HRV. Longitudinal studies and examination of potential mediating factors in this CRTI-HRV relationship are needed.

The effects of acute hypoxia on tissue oxygenation and circulating alarmins in healthy adults.

The binding of high-mobility group box-1 (HMGB-1) to the membrane receptor for advanced glycation end-products (mRAGE) is a key early mediator of non-infectious inflammation and its triggers include ischaemia/hypoxia. The effects of acute hypoxia on soluble RAGE (sRAGE) are unknown. Fourteen healthy adults (50 % women; 26.6+/-3.8 years) were assessed at baseline normoxia (T0), followed by four time-points (T90, 95, 100 and 180 min) over three hours of continuous normobaric hypoxia (NH, 4,450 m equivalent) and again 60 min after return to normoxia (T240). A 5-min exercise step test was performed during NH at T90. Plasma concentrations of HMGB-1, sRAGE VCAM-1, ICAM-1, VEGF IL-8 and IL-13 were measured using venous blood. Arterial and tissue oxygen saturations were measured using pulse oximetry (SpO(2)) and near-infrared spectroscopy (StO(2)), respectively. NH led to a significant reduction in SpO(2), StO(2), sRAGE and VEGF, which was compounded by exercise, before increasing to baseline values with normoxic restoration (T240). NH-exercise led to a paired increase in HMGB-1. sRAGE inversely correlated with HMGB-1 (r=-0.32; p=0.006), heart rate (r=-0.43; p=0.004) but was not linked to SpO(2) or StO(2). In conclusion, short-term NH leads to a fall in sRAGE and VEGF concentrations with a transient rise post NH-exercise in HMGB-1.

Heart rate variability and plasma nephrines in the evaluation of heat acclimatisation status.

PURPOSE: Heat adaptation (HA) is critical to performance and health in a hot environment. Transition from short-term heat acclimatisation (STHA) to long-term heat acclimatisation (LTHA) is characterised by decreased autonomic disturbance and increased protection from thermal injury. A standard heat tolerance test (HTT) is recommended for validating exercise performance status, but any role in distinguishing STHA from LTHA is unreported. The aims of this study were to (1) define performance status by serial HTT during structured natural HA, (2) evaluate surrogate markers of autonomic activation, including heart rate variability (HRV), in relation to HA status. METHODS: Participants (n = 13) were assessed by HTT (60-min block-stepping, 50% VO2peak) during STHA (Day 2, 6 and 9) and LTHA (Day 23). Core temperature (Tc) and heart rate (HR) were measured every 5 min. Sampling for HRV indices (RMSSD, LF:HF) and sympathoadrenal blood measures (cortisol, nephrines) was undertaken before and after (POST) each HTT. RESULTS: Significant (P < 0.05) interactions existed for Tc, logLF:HF, cortisol and nephrines (two-way ANOVA; HTT by Day). Relative to LTHA, POST results differed significantly for Tc (Day 2, 6 and 9), HR (Day 2), logRMSSD (Day 2 and Day 6), logLF:HF (Day 2 and Day 6), cortisol (Day 2) and nephrines (Day 2 and Day 9). POST differences in HRV (Day 6 vs. 23) were + 9.9% (logRMSSD) and - 18.6% (logLF:HF). CONCLUSIONS: Early reductions in HR and cortisol characterised STHA, whereas LTHA showed diminished excitability by Tc, HRV and nephrine measures. Measurement of HRV may have potential to aid real-time assessment of readiness for activity in the heat.

The British Services Dhaulagiri Medical Research Expedition 2016: a unique military and civilian research collaboration.

INTRODUCTION: High-altitude environments lead to a significant physiological challenge and disease processes which can be life threatening; operational effectiveness at high altitude can be severely compromised. The UK military research is investigating ways of mitigating the physiological effects of high altitude. METHODS: The British Service Dhaulagiri Research Expedition took place from March to May 2016, and the military personnel were invited to consent to a variety of study protocols investigating adaptation to high altitudes and diagnosis of high-altitude illness. The studies took place in remote and austere environments at altitudes of up to 7500 m. RESULTS: This paper gives an overview of the individual research protocols investigated, the execution of the expedition and the challenges involved. 129 servicemen and women were involved at altitudes of up to 7500 m; 8 research protocols were investigated. CONCLUSIONS: The outputs from these studies will help to individualise the acclimatisation process and inform strategies for pre-acclimatisation should troops ever need to deploy at high altitude at short notice.

The effect of high altitude on central blood pressure and arterial stiffness.

Central arterial systolic blood pressure (SBP) and arterial stiffness are known to be better predictors of adverse cardiovascular outcomes than brachial SBP. The effect of progressive high altitude (HA) on these parameters has not been examined. Ninety healthy adults were included. Central BP and the augmentation index (AI) were measured at the level of the brachial artery (Uscom BP+ device) at <200 m and at 3619, 4600 and 5140 m. The average age of the subjects (70% men) were 32.2±8.7 years. Compared with central arterial pressures, brachial SBP (+8.1±6.4 mm Hg; P<0.0001) and pulse pressure (+10.9±6.6 mm Hg; P<0.0001) were significantly higher and brachial diastolic BP was lower (-2.8±1.6 mm Hg; P<0.0001). Compared with <200 m, HA led to a significant increase in brachial and central SBP. Central SBP correlated with AI (r=0.50; 95% confidence interval (CI): 0.41-0.58; P<0.0001) and age (r=0.32; 95% CI: 21-0.41; P<0.001). AI positively correlated with age (r=0.39; P<0.001) and inversely with subject height (r=-0.22; P<0.0001), weight (r=-0.19; P=0.006) and heart rate (r=-0.49; P<0.0001). There was no relationship between acute mountain sickness scores (Lake Louis Scoring System (LLS)) and AI or central BP. The independent predictors of central SBP were male sex (coefficient, t=4.7; P<0.0001), age (t=3.6; P=0.004) and AI (t=7.5; P<0.0001; overall r2=0.40; P<0.0001). Subject height (t=2.4; P=0.02), age (7.4; P<0.0001) and heart rate (t=11.4; P<0.0001) were the only independent predictors of AI (overall r2=0.43; P<0.0001). Central BP and AI significantly increase at HA. This rise was influenced by subject-related factors and heart rate but not independently by altitude, LLS or SpO2.

The Hearts of Heroes: the epidemiology of cardiac disease in the UK Armed Forces.

When the general public look from the outside at the armed services, their impression is often one of earnest young men and women who are the pinnacle of physical fitness and health, and put their lives on the line for their country. There is usually sadness and respect for those killed on active operations, having put themselves in harm's way. Therefore, when the public discover that more than 1 in 10 deaths in the UK Armed Forces are due to cardiovascular disease, the air of sadness is invariably replaced with surprise and disbelief. These figures, while lower than those due to deaths in accidents, are approaching the numbers of those due to suicide in the armed services; yet deaths from cardiac disease are barely recognised by society, in spite of many of them being avoidable. This article reviews the epidemiology of cardiac disease in the UK Armed Forces, both in terms of morbidity and mortality. It outlines current understanding and gaps in the knowledge regarding the burden of cardiovascular disease in the military population. The particular demographics of the Armed Forces and its influence on cardiac disease burden are discussed. The role of inherited and congenital diseases in younger servicemen and women is highlighted, as is the trend that with increasing age, the burden of disease shifts to ischaemic heart disease, which becomes the dominant cause of both death and disability.

Pericarditis and pericardial effusions in the military patient.

The pericardium is the thin double-walled sac encapsulating the heart which has a number of important physiological roles including fixing the heart in the mediastinum, protecting it from cross-organ infection (eg, lung) and lubricating cardiac contraction. The pericardium is associated with several disease syndromes that occasionally affect the military population. These include acute and recurrent pericarditis, pericardial effusion and tamponade, which may result from a large number of different aetiological agents. Pericardial diseases have a wide range of clinical manifestations and the diagnosis of pericardial diseases can be a challenge. This article reviews the anatomy and pathophysiology of pericarditis and pericardial effusions before outlining their clinical features, recommended investigations and management options. Particular emphasis is placed on the impact of these diseases for patients in a military occupational environment.

Screening for cardiac disease in potential recruits to the British Army.

The British Army screens potential recruits for disease, including cardiovascular disease, at the pre-employment medical assessment in the Army Selection Centres. The epidemiology of cardiovascular disease in the Armed Forces coupled with the high physical demand placed on the cardiovascular system, often in remote locations make screening desirable. This is particularly pertinent as servicemen and women die from cardiovascular disease each year. To evaluate this particular screening system it is essential to understand the aim of the system, how it is designed and how screening systems in general are evaluated. The efficacy of a screening test is quantified using the measurements of sensitivity, specificity and likelihood ratios. These measurements are defined and the pitfalls associated with evaluating a screening system are described. The different screening tests used to identify cardiac disease and their individual strengths and weaknesses, are illustrated. Finally the article reviews the previous British Army recruit cardiac screening system, that used a stereotyped history and physical examination and the newer system that replaced it, which includes the incorporation of the 12-lead ECG and on site echocardiography in individuals revealing abnormalities on history, examination or ECG.

Managing the military patient with syncope.

Syncope is a relatively common occurrence in military populations. It is defined as a transient loss of consciousness due to global cerebral hypoperfusion, characterised by a rapid onset, short duration and a spontaneous and complete recovery. While the symptom of syncope is easily elicited, discovering the mechanism can be more problematic and may require a plethora of diagnostic tests. The aim of this paper is to review current evidence pertaining to the classification, investigation and management of syncope, from a military perspective. Emphasis is placed on assisting primary healthcare professionals in the assessment and management of syncope, in the UK and on operations, while providing explicit guidance on risk. The occupational limitations required in safely managing patients with syncope are stressed along with the potential long-term limitations.

Cardiomyopathies and the Armed Forces.

Cardiomyopathies are a group of heterogeneous myocardial diseases that are frequently inherited and are a recognised cause of premature sudden cardiac death in young individuals. Incomplete expressions of disease and the overlap with the physiological cardiac manifestations of regular intensive exercise create diagnostic challenges in young athletes and military recruits. Early identification is important because sudden death in the absence of prodromal symptoms is a common presentation, and there are several therapeutic strategies to minimise this risk. This paper examines the classification and clinical features of cardiomyopathies with specific reference to a military population and provides a detailed account of the optimum strategy for diagnosis, indications for specialist referral and specific guidance on the occupational significance of cardiomyopathy. A 27-year-old Lance Corporal Signaller presents to his Regimental medical officer (RMO) after feeling 'light-headed' following an 8 mile unloaded run. While waiting to see the RMO, the medical sergeant records a 12-lead ECG. The ECG is reviewed by the RMO immediately prior to the consultation and shows voltage criteria for left ventricular (LV) hypertrophy and inverted T-waves in II, III, aVF and V1-V3 (Figure 1). This Lance Corporal is a unit physical training instructor and engages in >10 h of aerobic exercise per week. He is a non-smoker and does not have any significant medical history.

Myocarditis and the military patient.

Myocarditis, simply defined as inflammation of the heart muscle, is a commonly encountered cardiac disease in primary and secondary care, both in the UK and on Operational deployments. In the UK Armed Forces, myocarditis results in deaths as well as the premature termination of military careers on medical grounds. The aetiology is usually the result of a number of infectious aetiologies with viruses being the most common pathogens in the vast majority of cases. However, it may also be the result of autoimmune activation, chemical or pharmacological toxins, environmental insult or hypersensitivity reactions. Particular aetiologies that are more likely to be seen in a military population are discussed and include certain infections, smallpox vaccine, and hyperthermia and hypothermia. The clinical features can be highly variable ranging from an asymptomatic infection to fulminant heart failure. Features pertinent to the military doctor, including the natural history, investigative modalities and management strategies, with a particular emphasis on the occupational impact of myocarditis in the UK Armed Forces are reviewed.

Copeptin and arginine vasopressin at high altitude: relationship to plasma osmolality and perceived exertion.

PURPOSE: A diuresis is a key part of acclimatisation to high altitude (HA). Arginine vasopressin (AVP) is a hormone involved in salt and water balance and may potentially have a role in the development of altitude illness. ProAVP (copeptin) is more stable than AVP and is assayed by a straightforward, automated method. We investigated the relationship of AVP to copeptin and the copeptin response to exercise and altitude illness in a large cohort during a field study at HA. METHODS: 48 subjects took part in a 10-day trek at HA. Venous blood samples were taken at 3,833, 4,450 and 5,129 m post-trek (exercise) and the following day at rest. Daily recordings of symptoms of altitude illness, oxygen saturations and perceived exertion were carried out. RESULTS: AVP and copeptin levels increased with exercise and correlated closely (ρ 0.621 p < 0.001), this was strongest in the stressed state when AVP secretion was highest, at 5,129 m post-exercise (ρ 0.834 p < 0.001). On two-way ANOVA, both altitude (F = 3.5; p = 0.015) and exercise (F = 10.2; p = 0.002) influenced copeptin levels (interaction F = 2.2; p = 0.08). AVP levels were influenced by exercise (F = 14.4; p = 0.0002) but not altitude (F = 2.0; p = 0.12) with no overall group interactions (F = 1.92.6; p = 0.06). There was no association between copeptin or arginine vasopressin and altitude illness. Copeptin correlated with the Borg RPE score and was significantly higher in the group with a Borg score ≥15 (7.9 vs. 3.7 p < 0.001). CONCLUSION: We have shown that arginine vasopressin and copeptin levels correlate and are suppressed below 5,129 m. Furthermore, we have demonstrated that exertion, rather than altitude illness or increasing osmolality, is the stimulus for increases in copeptin.

Comparison of two methods of assessing total body water at sea level and increasing high altitude.

Fluid retention is a recognized feature of acute mountain sickness. However, accurate assessment of hydration, including the quantification of body water, has traditionally relied on expensive and non-portable equipment limiting its utility in the field setting. We compared the assessment of total body water (TBW) and their relationship to total body weight using two non-invasive methods using the NICas single-frequency bioimpedance analysis (SF-BIA) system and the BodyStat QuadScan 4000 multifrequency BIA system (MF-BIA). TBW measurements were performed at rest at sea level and at high altitude (HA) at 3833 m postexercise and at rest and thereafter at rest at 4450 m and 5129 m on 47 subjects. The average age was 34.5 ± 9.3 years with an age range of 21-54 years (70.2% male). There were strong correlations between TBW assessment with both methods at sea level (r = 0.90; 95% CI 0.78-0.95: P<0.0001) and at HA (r = 0.92; 0.89-0.94: P<0.0001), however, TBW readings were 0.2 l and 1.91 l lower, respectively, with the NICaS. There was a stronger correlation between TBW and body weight with the QuadScan (r = 0.91; P<0.0001) than with the NICaS (r = 0.83; P<0.0001). The overall agreement between the two TBW methods was good, but the 95% confidence intervals around these agreements were relatively wide. We conclude that there was reasonable agreement between the two methods of BIA for TBW, but this agreement was lower at HA.

Brain natriuretic peptide and NT-proBNP levels reflect pulmonary artery systolic pressure in trekkers at high altitude.

Our objective was to evaluate the utility of the natriuretic peptides BNP (brain natriuretic peptide) and NT-proBNP as markers of pulmonary artery systolic pressure (PASP) in trekkers ascending to high altitude (HA). 20 participants had BNP and NT-proBNP assayed and simultaneous echocardiographic assessment of PASP performed during a trek to 5150 m. PASP increased significantly (p=0.006) with ascent from 24+/-4 to 39+/-11 mm Hg at 5150 m. At 5150 m those with a PASP>/=40 mm Hg (n=8) (versus those with PASP<40 mm Hg) had higher post-exercise BNP (pg/ml): 54.5+/-36 vs. 13.4+/-17 (p=0.012). Their resting BNP at 5150 m was also higher: 57.3+/-43.4 vs. 12.6+/-13 (p=0.017). In those with a pathological (>/=400 pg/ml) rise in NT-proBNP at 5150 m (n=4) PASP was significantly higher: 45.9+/-7.5 vs. 32.2+/-6.2 mm Hg (p=0.015). BNP and NT-proBNP may reflect elevated PASP, a central feature of high altitude pulmonary oedema, at HA.

[Recreational athletes and doping--a survey in 11 gyms in the area of Frankfurt/Main]. / Doping bei Freizeitsportlern--Eine Untersuchung in 11 Fitnessstudios im Raum Frankfurt am Main.

BACKGROUND: Doping no longer concerns exclusively competitive sports, but also recreational sports. METHOD: Survey of 484 recreational athletes in 11 gyms in the area of Frankfurt/Main. RESULTS: 12.9% of the men and 3.6% of the women reported to take anabolic drugs. Theyconsumed anabolic steroids (100%; 35% p.o., 71% parenterally), stimulants (14%) and growth hormone (5%). Suppliers were friends (39%), sports mates (28%), physicians (28%) and coaches (6%). The acquisition costs amounted to an average intake over 9 weeks to 175 Euro. Information about doping side effects came from literature (67%), physicians (38%), sports mates and the so-called Black Book (14% respectively), coaches, friends and Internet (5% respectively). 2% of the athletes with abuse of doping substances were smokers, 11% had a drink several times a week, 3% also consumed other drugs, 35% had consumed other drugs in the past. Abusers of doping substances primarily intended to increase muscle size (86%) and strength (61%). CONCLUSION: From a sports medical point of view it is concerning that the proportion of doping drugs prescribed by physicians has doubled in the decade after the publication of the predecessor study in Northern Germany despite optimized sports medical and legal education measures.

The effects of acute hypobaric hypoxia on arterial stiffness and endothelial function and its relationship to changes in pulmonary artery pressure and left ventricular diastolic function.

This study investigated, for the first time, the effects of simulated high altitude, following acute hypobaric hypoxia (HH), on simultaneous assessment of large artery stiffness and endothelial function and its inter-relationship to left ventricular (LV) diastolic function, pulmonary artery systolic pressure (PASP), and estimated PA vascular resistance (PVR). Ten healthy subjects were studied at baseline pre and following acute HH to 4800 m for a total of 180 minutes. Assessments of LV diastolic function, mitral inflow, estimated LV filling pressure (E/e'), PVR, and PASP were undertaken using transthoracic echocardiography. Simultaneous assessments of arterial stiffness index (SI), systemic vascular resistance (SVR), vascular tone, and endothelial function (reflective index [RI]) were performed using pulse contour analysis of the digital arterial waveform. Acute hypoxia led to a fall in SpO2 (98.1±0.7 vs. 71.8±7.1%; p=0.0002), SVR (1589.1±191.2 vs. 1187.8±248.7; p=0.004), and RI (50.8±10.3 vs. 33.0±6.5%; p=0.0008) with an increase in PASP (24.3±2.2 to 35.0±5.3 mmHg; p=0.0001) and estimated PVR (116.40±19.0 vs. 144.6±21.5; p<0.001). There was no rise in either SI (p=0.13), mitral early annular early e' filling velocity or E/e'. There was a significant inverse correlation between SpO2 and PASP (r=-0.77; p<0.0001), PVR (r=-0.57; p=0.008) and between the fall in SpO2 and change (Δ) in RI (baseline vs. 150 min, r=-0.52; p<0.001). There was a modest inverse correlation between ΔRI (lower ΔRI=worsening endothelial function) and ΔPAP (r=-0.55; p=0.10) and a strong inverse correlation between ΔRI and ΔPVR (r=-0.89; p=0.0007). Acute hypobaric hypoxia does not significantly alter large artery stiffness or cause overt LV diastolic function. However, the degree of hypoxia influences both the systemic endothelial and pulmonary vascular responses. This noted association is intriguing and requires further investigation.

Severe acute mountain sickness, brain natriuretic peptide and NT-proBNP in humans.

AIM: To examine the response of brain natriuretic peptide (BNP) and NT-proBNP to high altitude (HA) both at rest and following exercise. METHODS: We measured NT-proBNP and BNP and Lake Louise (LL) acute mountain sickness (AMS) scores in 20 subjects at rest in Kathmandu (Kat; 1300 m), following exercise and at rest at 4270 and 5150 m. RESULTS: BNP and NT-proBNP (pg ml(-1) , mean ± SEM) rose significantly from Kat (9.2 ± 2 and 36.9 ± 6.6, respectively) to arrival at 4270 m after exercise (16.6 ± 4 and 152 ± 56.1, P=0.008 and P<0.001, respectively) and remained elevated the next morning at rest (28.9 ± 9 and 207.4 ± 65.1, P = 0.004 and P<0.001 respectively). At 5150, immediately following ascent/descent to 5643 m, BNP and NT-proBNP were 32.3 ± 8.8 and 301.1 ± 96.3 (P=0.003 and P<0.001 vs. Kat, respectively) and at rest the following morning were 33.3 ± 9.7 and 258.9 ± 89.5 (P=0.008 and P=0.001 vs. Kat respectively). NT-proBNP and BNP correlated strongly at 5150 m (ρ 0.905, P<0.001 and ρ 0.914, P<0.001 for resting and post-exercise samples respectively). At 5150 m, BNP levels were significantly higher among the four subjects with severe (LL score>6) AMS (58.4 ± 18.7) compared with those without (BNP 22.7 ± 8.6, P=0.048). There were significant correlations between change in body water from baseline to 5150 m with both BNP and NT-proBNP (ρ 0.77, P=0.001, ρ 0.745, P=0.002 respectively). CONCLUSION: In conclusion, these data suggest that BNP and NT-proBNP increase with ascent to HA both after exercise and at rest. We also report the novel finding that BNP is significantly greater in those with severe AMS at 5150 m.

The use of exercise and dietary supplements among British soldiers in Afghanistan.

BACKGROUND AND OBJECTIVES: Recently published case reports, coupled with a large observational study of 1017 deployed servicemen to Iraq (January 2009), has highlighted the issue and potential concerns regarding the unregulated use of dietary and exercise supplements within the British military. Consequently, an exploratory pilot study was undertaken to assess whether the findings of the previous Iraq study were applicable to current deployed British servicemen in Afghanistan. METHODS: This was a voluntary questionnaire-based study targeted at individuals attending a health promotion fair in Camp Bastion, Afghanistan in June 2010. RESULTS: From 150 questionnaires handed out there were 87 completed questionnaires (58% return). The mean age was 28.0 (SD 7.1; range of 18-50 years) with 89.7% being male. From the total of 87 persons 46.0% were self-declared current smokers with 37.9% admitting to drinking >6 caffeinated drinks per day. Forty nine persons (56.3%) admitted to a history of supplement use with 35 (40.2% compared with 32.0% in 2009 in Iraq) declaring current use. The average duration of supplement use among current users was 3.0 (2.0-9.0) months. The main sources of supplement supply were via local NAAFI purchase (57.1%), internet purchase (40.0%) and via their local chemist (2.9%). The main types of supplement used were proteins/amino acids (85.7%), creatine (34.3%), chromium (31.4%), stimulants (17.1%), hydroxycut (5.7%), and testosterone boosters (1.2%) with no persons admitting to the use of ephedra or anabolic steroids. CONCLUSIONS: A significant proportion of the British servicemen employed on operations in Afghanistan who were sampled, admitted to current dietary and exercise supplement use whilst on deployment. The results of this small study suggest that their use on operations may be increasing. Smoking rates and caffeine consumption, on deployment, remain high in the British military. A larger detailed study with greater representation among soldiers deployed to forward operating bases would be helpful to fully appreciate the scale of supplement use.