Article Text
Abstract
Introduction Exertional heat illness (EHI) is recognised as a significant problem for fit young individuals taking part in strenuous activity in temperate climates. The aim of this research was to relate episodes of reported EHI against known risk factors for heat illness and determine whether modification of the training programme had an effect on the number of cases reported. Publication was not possible when the work was originally conducted in 2000 because of barriers within Royal Military Academy Sandhurst (RMAS) at the time.
Methods A retrospective study examined the medical data for Officer Cadets in training at the RMAS for a 2-year period ending April 2000.
Results 60 cases were initially reported as EHI, in 58 individuals. Using the following criteria; dizziness, collapse, reduced conscious level, headache, nausea, vomiting, elevated core (rectal) temperature and the results of urine and blood tests, 35 cases were diagnosed as EHI and 25 cases had other diagnoses recorded after investigation. Minority of cases (n=12) had an identifiable risk factor but the majority appeared to be fit young individuals who were susceptible to EHI in conditions where the rest of the population was unaffected.
Discussion Further work is planned to study individuals during strenuous activity events in the hope of accurately identifying those at risk and further reducing the incidence of EHI. EHI is common, case definition is poor, risk factors are not present in all individuals but modification of training programmes is effective.
- occupational & industrial medicine
- sports medicine
- epidemiology
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Key messages
This paper fills an important gap in the exertional heat illness (EHI) literature, while demonstrating a progressive approach to training and commitment to organisational learning within the British Army.
Its publication offers opportunity to disseminate best practice beyond Royal Military Academy Sandhurst, which continues to model the prevention, detection and treatment of the inevitable incidence of EHI in military personnel.
Demonstrates the importance of correct diagnosis through detailed history and examination in a timely fashion as practically possible.
Introduction
From 1993 to 20 July 1998, 579 service personnel in the armed forces were referred to secondary care with a diagnosis of heat illness. The majority of these were army (516). There were two deaths, one army and one navy (Royal Marines).1 The risk factors for exertional heat illness (EHI)2 are related to the individual; concurrent illness, previous history of EHI, obesity, lack of physical fitness, poor acclimatisation, sweat gland dysfunction, alcohol and drugs and to the environment; environmental temperature and humidity, exertion, lack of food, water or sleep and wearing protective clothing. The typical military heat casualty is male, heavier and less fit than his colleagues, typically taking part in a team pursuit where he is encouraged to maximum physical effort.3 4
Reports of cases from Royal Military Academy Sandhurst (RMAS) suggest that these do not fit into the stereotype described above. Undoubtedly, there are a few exceptions where those less well adapted or with precipitating factors have suffered from EHI but there are also a minority of extremely fit, lean young men taking part in individual best effort events who have been heat intolerant.
The aim of this retrospective case study was to examine all cases who had initially been identified as EHI, determine how many of these were genuinely EHI and identify if there were any factors making them susceptible to heat illness. The training programme at RMAS is constantly reviewed and the effect on the incidence of EHI form these changes was noted.
Methods
The Commissioning Course for officer cadets at the RMAS is a 1-year course, which combines academic study with military and physical training. It is divided into three 14-week terms and recess periods of three or 4 weeks during which the officer cadets spend time Adventurous Training and are given maintenance fitness training programmes. New intakes arrive at RMAS every January, May and September, therefore, at any time there are up to seven hundred officer cadets from three terms training in the same conditions.
Officer cadets potentially suffering from EHI were identified retrospectively from the LAND Command Climatic Injury Report Forms (Annex A to Med 317 728 dated 28 July 1998) held in the Medical Reception Station (MRS) at Sandhurst. The MRS is a medical centre with prehospital resuscitation facilities and beds for 16 patients. The author then completed a search on the primary healthcare computer system (Meditel) using the search criteria: ‘collapse’, ‘syncope’ or ‘heat; accident caused by’. The symptoms and signs used to identify an episode of heat illness were; dizziness, staggering, reduced conscious level, collapse, headache, nausea, vomiting, elevated core (rectal) temperature, hot dry skin or still sweating, tachycardia or hypotension. The results of urine and blood tests (haematuria, proteinuria and raised serum creatine kinase (CK) level) were used to support the diagnosis.
Many of these symptoms are common to both simple exertional fatigue and EHI and it is very difficult to distinguish between the two at presentation. A heat illness casualty may deteriorate rapidly, therefore, a presumptive diagnosis was made in all officer cadets presenting with any clinical features of EHI and they were treated accordingly. Admission to Frimley Park Hospital was arranged for all cases with an initial recorded rectal temperature greater than 40°C or any officer cadet about whom there was any clinical concern, in accordance with Joint Service Instructions.5
The following clinical observations are recorded in all cases; conscious level expressed as Glasgow Coma Scale score (GCS), rectal temperature, blood pressure and pulse. The nature of the activity causing the episode, how the officer cadet presented, that is, headache after run or collapse with reduced conscious level and any predisposing factors were recorded in the patient notes along with the treatment provided and outcome for all patients.
The computer notes for these officer cadets were checked to identify individual precipitating factors such as age, sex, concurrent illness, previous EHI and the use of drugs or alcohol. Body mass index (BMI as kg/m2) was used as a simple index of obesity and is recorded as part of the initial medical on arrival at RMAS. Physical fitness was assessed using the basic fitness test (BFT) which is a best effort run time for 1.5 miles and has been the standard test for assessing physical fitness in military personnel for a number of years. All new officer cadets at RMAS complete a BFT within the first few weeks of term and these times were obtained from the RMAS Gymnasium records.
Environmental predisposing factors such as lack of sleep, food or water and clothing worn were identified from the patient notes. The stress of the environmental conditions was recorded using Wet Bulb Globe Temperature (WBGT) readings obtained from the Gymnasium at RMAS. The length of time that each officer cadet had been in training was expressed as week number of the three terms. The acclimatisation for each officer cadet was not quantified but at any time there are officer cadets in each of the three intakes exercising under the same climatic conditions.
The number of officer cadets in each intake was obtained from RMAS records. This was expressed as incidence per term, spring, summer and autumn for the 2-year period.
The data were analysed using the MS Excel Word for Windows spreadsheet.
Results
Number of cases
Sixty episodes in 58 individuals were initially reported as heat illness in a 2-year period from May 1998 to April 2000. The following analysis is of all cases initially considered to be EHI. Of these 25 cases showed no change in GCS, no hypotension, no raised CK and only mildly raised rectal temperature <39°C but had other reasons for feeling unwell during the exercise hence attended the MRS. The number of cases confirmed as EHI after investigation was therefore only 35 officer cadets.
Incidence
The number of strenuous physical events per term was multiplied by the number of officer cadets taking part in each event. The incidence was then calculated and expressed as number of cadets suffering EHI per 1000 cadets taking part in a physical training event. The incidence was recorded for each term over the 2-year period, table 1.
Reduced conscious level
Ten cases showed a reduced conscious level. Nine had mildly reduced GCS of 13–14/15 and were reported as being disorientated. In several cases, they were verbally or physically aggressive and required some restraining in order to treat. The one fatal case arrived at the MRS with a GCS of 4/15.
Temperature at presentation
A wide range of initial rectal temperatures was seen for all forms of collapse (figure 1). The mean temperature at presentation was 39.8°C. The range was 36.5°C–43°C and the median 39.7°C.
Blood pressure
Only one case was hypotensive, this was the fatal case.
CK level
CK levels were measured for all Officer Cadets managed by the MRS at 4 hours then days 3, 5, 7 and 10 if not returned to normal by day 7. Those admitted to hospital had levels measured most days. The results are therefore not directly comparable but the range of peak CK values was from 59 to 47 407 and the median was 595IU/L.
Individual risk factors
Age
The age range was 19–26 years, the median and mode were 23 years.
Gender distribution
Fifty-two male, six female. The percentage of female officer cadets at RMAS is approximately 15%, however, the incidence of EHI was only 11% and half of these were reclassified as not EHI after investigation. The true incidence of EHI in female officer cadets was therefore 8.5%.
Previous history of heat illness
Seven cases had a previous episode of EHI, see table 2. The time scale was from 3 weeks to 5 years.
Concurrent illness
Twenty-nine cases had concurrent illness or reported symptoms within the preceding week. Most of these were noted in follow-up appointments after recovery from the episode of collapse. The main complaints were diarrhoea and vomiting (4 cases), upper respiratory tract infections, URTI (11 cases) and lower respiratory tract infections (7 cases). Two continued to have temperatures up to 39.5°C 24 hours after presenting to the MRS. A further seven officer cadets reported after the event that they had felt non-specifically unwell prior to their episode. None of these had reported their illness to the MRS. One individual had had vaccinations 48 hours prior to his collapse. Two female officer cadets were found to be anaemic (haemoglobin 98 and 110 g/L).
Alcohol and drugs
Only two officer cadets had had any alcohol within 24 hours of an episode of collapse, neither had exceeded four units. No officer cadet admitted to having taken any form of recreational drugs.
Ethnicity
Four Overseas students were initially included in the study; one was suffering from a viral URTI and the other was excluded as muscular pain. Neither had raised rectal temperatures or CK level; therefore, were reclassified as not EHI. Of the remaining two, one presented with a rectal temperature of 43°C, was admitted to hospital and spent 1 day on the high dependency unit. He was repatriated rather than completing his RMAS training after a period on the ‘Y list’ which is a holding platoon for those awaiting treatment or recovering from injury. The second was on a first term exercise and ran without removing thermal clothing that he had been wearing overnight. In addition, he was strongly predisposed to heat illness with a BMI of 35.8 kg/m2 and BFT time of 21.23 min, over twice the time allocated to pass. He was allowed to start the commissioning course at RMAS but was receiving remedial physical training in camp rather than taking part in normal PT sessions. He has now been successfully commissioned. All four officer cadets came from far hotter countries than the UK but had not done any military training in their home countries.
Obesity
Figure 2 shows the BMI of the 58 officer cadets as measured at their initial entry medical, two male officer cadets had two episodes of EHI therefore their BMI is represented twice each. Obesity in male recruits has been described as BMI >27 kg/m2. BMI >26 kg/m2 but <27 kg/m2 may be classified as overweight. Of fifty-four, six (11.1%) of the male officer cadets were obese and 6/54 (11.1%) overweight. Forty-two of the 54 male officer cadets (77.7%) were lean. The mean value was 24.5 kg/m2, the range 18.1–35.8 kg/m2 and the median 24.4 kg/m2. The females had mean BMI of 25.3 kg/m2, range 22.3–28.7 kg/m2 and the median was 24.8 kg/m2.
Basic fitness test
Figure 3 shows the BFT times for officer cadets initially treated as EHI. Only one male officer cadet failed the BFT. A high proportion of the male officer cadets, 61% scored A grades (<9 min 07 s), 30% B grade (<9 min 48 s), 7% C grade (<10 min 30 s). The females all passed; 20% A (<10 min 45 s), 60% B (<11 min 40 s) and 20% C (<12 min 30 s). The BFT times were only available for 41 of the 58 officer cadets.
Environmental risk factors
The maximum recorded WBGT when an incidence of EHI occurred was 21.9°C. The range was 10.2°C–21.9°C. The WBGT threshold value of 25°C indicates the combat fitness test (CFT) as the maximum work rate.5
No officer cadet reported being short of water provision although six considered themselves less than optimally hydrated prior to exercising.
Lack of sleep
Seven officer cadets admitted to having had late nights prior to exercise. Mostly this was due to taking advantage of an evening off and relaxing watching television, not due to programmed events.
Lack of food
Two officer cadets reported not having had breakfast prior to running; one due to nausea, the other did not give a reason.
Activity
During the period, studied officer cadets completed 42 endurance training periods and 7 endurance events in their year at RMAS. The endurance periods represent a graded exercise programme preparing the cadets for RMAS competition events and military service. These were the Steeplechase, Log race, March-and-Shoot and Endurance competitions, the CFT and Commandant’s Individual Fitness Test (CIFT). The content, distance, format and timing of these competition events was amended throughout the study period in order to provide the best training programme and minimise EHI risk. As shown in figure 4, only 19% of EHI cases occurred during regular routine endurance training although this comprises 85% of the physical training in camp.
Term
Figure 5 illustrates the occurrence of EHI related to term. Term 1, week 3, there were five cases on exercise. The five cases during week 14 were on the steeplechase, which is the first individual best effort competition event that the officer cadets take part in. In term 2 in 1998, there was a log race competition which caused three cases in week 18. Nineteen cases occurred on the CIFT or CFT, which have been held during weeks 23–25. The CIFT is no longer conducted at RMAS. Term 3 starts with three competition events; log race, endurance competition and march-and-shoot around weeks 29–34. A few weeks later, the officer cadets complete a CFT and the annual combat fitness test (ACFT), which is a two mile run, followed by three military tasks.
Outcomes (as at May 2000)
Twenty-seven cases were admitted to hospital, three after a delay. The average length of admission was 3.5 days. The remaining 33 cases were managed in the MRS. The average length of stay was 1 day. All cases of EHI were medically downgraded for an appropriate period according to the DCI.5 There was one death and five officer cadets were medically discharged. One was medically downgraded for 3 months but subsequently withdrawn from the commissioning course. Five were still in training as at May 2000. Forty-six officer cadets who had suffered from EHI were successfully commissioned by April 2000.
Discussion
There were 60 cases initially treated as EHI, however, after investigation the diagnosis was only applicable to 35 officer cadets.
The peak incidence occurred in the Summer term 1998. Many changes were implemented at the academy and the following summer the incidence was less than half. This is on a background of heightened awareness of the problem, better supervision and therefore more stringent reporting of any possible cases.
Individual risk factors
Tolerance of extremes of temperature is reduced with increasing age in adults. Young men have been shown to have lower skin temperatures and evaporate more sweat per degree of core temperature rise than older men.6 This research was performed on two groups aged 20–30 years and 45–70 years. The population at RMAS all fall into the young bracket therefore age is not a risk factor in this study.
Studies7 have shown little difference between males and females once corrected for aerobic fitness. Logically females should dissipate heat less effectively due to lower sweating rates and possibly their thicker layer of subcutaneous fat, however, they generate less exertional heat having smaller muscle bulk and have higher surface area to mass ratio. Body water may, therefore, be conserved rather than wasted. In this study, the incidence of EHI in female officer cadets was lower than expected suggesting that other factors are more important.
Work done by the Defence Evaluation and Research Agency into providing new guidelines for army personnel working in the heat assumed upper acceptable limit of core temperature as 38.0°C under laboratory conditions. Above 38.9°C was considered unacceptable risk8 ,9 . This is a widely accepted tolerable extreme core temperature. In this study, rectal temperature was measured with a thermometer which may not be accurate, may not demonstrate small temperature fluctuations and may not be diagnostic after the event10 . Core temperature is an unreliable guide to the severity of EHI,5 11 however, in order to be considered a case of heat illness it must be raised on measurement, ideally at the point of collapse or presentation of symptoms. The nature of training at RMAS means that the majority of physical events occur within the immediate vicinity and all major events have vehicle support. There is, therefore, very seldom any significant delay between first presentation and measurement of rectal temperature. Some cooling will occur en route to the MRS because the officer cadets and directing staff are trained to remove clothing and water cool anyone who could potentially be suffering from heat illness, water is carried on all events. All cases presenting to the MRS after exertion have rectal temperature taken as an immediate observation. In all cases where there was a delay between onset of symptoms and measurement of rectal temperature the officer cadet was assumed to be suffering from EHI because this diagnosis could not be excluded. One case involved four first term officer cadets on their first exercise in January 1999. The exercise ended with a 2 mile jog back to the transport, unfortunately not all the officer cadets had removed the extra, thermal clothing they had been wearing overnight. At the end of the short run four presented to the medical staff feeling unwell, none had collapsed. They were given oral fluids but no rectal temperature measurements were taken. They were then rested on the 4 hours bus journey back to RMAS and presented to the MRS 6 hours after feeling unwell. By this time, all had normal temperatures but all four had significantly raised CK levels and two were subsequently medically discharged.
Obesity is a significant risk factor in the development of heat illness.3 12 One case–control study12 found the OR for obese soldiers was 4.29 where obesity was defined as a BMI of greater than 27 kg/m2. Another very large case–control study (EHI n=528)13 was performed at a US Marine Corps basic training camp. They defined obesity as BMI greater than 26 kg/m2 and demonstrated a three fold increased risk of EHI for obese recruits. They considered BFT time with BMI and calculated a risk indication. High risk was a BMI >22 kg/m2 combined with a BFT time greater than 12 min for male recruits. This related to only one individual at RMAS. Medium risk was associated with a BMI of >26 kg/m2 and BFT time less than 12 min. Eleven individuals had a medium risk of whom the majority (7/11) were diagnosed as EHI. The remainder were low risk. The risk factor was not calculated for female recruits. In this study, BMI was measured at entry medical, however, most incidents of EHI occurred some time after this measurement was taken. The majority of officer cadets loose weight during the course, particularly during the first 5 weeks of term 1, therefore, the BMI recorded is likely to be an overestimate of their BMI at the time of the incident. Further research should match case controls to determine whether those suffering EHI were significantly heavier than their colleagues and also make an estimate of somatotype. Obesity was a significant risk factor affecting a minority of the cases of EHI at RMAS.
Fit individuals acclimatise well to heat and are at lower risk of developing EHI.14 Research by Mello et al 15 has shown that BFT time correlates well with VO2 max, therefore, may be used as an estimate of the fitness of the individual. Conversely BFT time may be used as an indicator of heat illness susceptibility. Gardner et al 13 demonstrated the OR for developing EHI with a BFT time greater than 12 mins was 3.4. In this study, only one officer cadet would have been considered high risk on the basis of BFT time.
There are very little data available to indicate the normal CK that would be expected in fit, young recruits performing regular strenuous exercise. Gardner and Kark found that the CK values of exercising military trainees frequently ranged from 500 to 900 IU/mL, but seldom above 1000 IU/mL.16 CK levels 12 hours after completing a 24-hour endurance event have been recorded as high as 3280 IU/mL where the individual showed no signs of heat illness (England M. MSU 1998). The minimum level that he recorded was 556 iu/mL. The optimum time for recording maximum CK is 24 hours,17 therefore, the maximum CK was probably in excess of 3280 IU/mL without EHI symptoms. In the RMAS study, CK was used as an aid to the diagnosis of EHI and as an indication of end organ damage.
Previous history of heat illness appears to be a very significant risk factor. A second episode may occur at any length of time after the first, may be more severe and the patient may show extremely rapid deterioration (Bergman BP, personal communication). This was certainly seen in the one fatal case at RMAS, however, is difficult to say whether EHI susceptibility predated the first incident or was caused by it. At RMAS, each officer cadet is counselled that they have suffered from EHI and therefore may be at risk of further illness for a considerable period. They are advised that they may be genetically predisposed to EHI and are given the option of terminating their military career if they consider this risk too great.
Febrile illness reduces the thermoregulatory capacity and increases the risk of heat illness. Individuals recovering from fever are more susceptible to heat illness even after all clinical evidence of illness has disappeared.18 Very often the officer cadet did not consider their symptoms to be serious enough to attend the MRS, hence took part in the event. This is despite every exercise period starting with a briefing from the physical training instructor instructing anyone who does not feel well, or has other reasons why they should not exercise to leave the lesson and attend the MRS.
Vaccinations can cause fever and there are cases in the literature of heat illness attributed to vaccinations. In one fatal case,19 the vaccinations had been given just 75 min prior to exercising and the loss of thermoregulatory control was compounded by the use of pseudoephedrine for weight loss. The programme at RMAS is arranged so that there is no physical exercises for 48 hours after vaccinations. One individual had had vaccinations 48 hours prior to his collapse. His hospital discharge letter stated vaccination allergy as cause for collapse rather than EHI. Two female officer cadets who walked in after the run complaining of tiredness were found to be anaemic. Neither had collapsed or had a raised CK and their temperatures were only mildly elevated (38.0°C and 38.5°C). They were, therefore, reclassified as not heat illness.
The questions regarding alcohol and drugs were asked in a totally confidential environment so the statistic is likely to be accurate. There is strong education about the danger of exercising after drugs or alcohol, which is presented to the officer cadets very early in the course. RMAS, like the rest of the Army, has regular compulsory drug testing and has not had any incidents of officer cadets testing positive.
The prevalence of heat intolerance has been estimated at 2%–4% young adults.20 It is unfortunately not yet possible to identify those susceptible although research is underway at Defence Evaluation and Research Agency (DERA) into chemical markers to predict poor response to heat. All officer cadets who suffer an episode that could possibly be EHI at RMAS are assessed in the Heat Chamber at the Institute of Naval Medicine before being allowed to return to training. One officer cadet has been advised against further military training as a result of this screening and medically discharged.
Motivation may well be the key to why RMAS has had cases of EHI in fit, young individuals without apparent risk factors. The majority of cases occurred during competition events and particularly those that are individual best effort. The competitions count towards being selected as the best platoon. The Sovereign’s Banner Platoon carry the Colours on the final parade and are publicly congratulated as the ‘top dogs’ of their intake. The majority of those who suffer from heat illness are fit, lean officer cadets who are working especially hard. Officer cadets are often extremely well motivated and appear to push themselves beyond their physiological limits.
Environmental risk factors
EHI rates increase with increasing WBGT.21–23 At RMAS the Defence Council Instruction (DCI) guidelines5 were strictly adhered to and yet there were cases of EHI even on cool days. Adherence to guidelines minimises the risk of EHI to 95% of normal personnel but approximately 5% of normal, healthy personnel will not be protected. Those who are not normal because of some intrinsic, genetic susceptibility to EHI or those who are not completely healthy even if they do not recognise their subclinical illness are not protected even when working within the guidelines.
Water discipline is considered very carefully at RMAS and strictly enforced according to the DCI guidelines and local policy.
The training programme at RMAS is carefully structured so that there are no late evening events prior to endurance events. Lights out is enforced at the beginning of the course but after the first term left to the officer cadets’ discretion.
Two officer cadets reported not having had breakfast prior to running. This is a low number indicates that the officer cadets understand the importance of regular meals.
Forced marches and military runs are known to be the primary activities causing heat casualties.21 24 25 In the UK, the generation of metabolic heat appears to be the primary cause of heat illness as opposed to environmental factors.24 The CFT is the most significant endurance event in Regular Army Units, however, most soldiers will only complete one or two CFT s each year due to operational tours, leave, courses or illness. At RMAS, each officer cadet completes seven competition events and 42 endurance periods in a 1-year period. Often repeat events are held for those who have missed out or failed the test. The frequency of exposure is therefore significantly higher than most operational Units and other training establishments. The CIFT in Term Two caused heat illness for two reasons. First it came after several weeks of less intense physical activity while the programme concentrated on tactical and academic issues. Second the nature of the CIFT, a combination of run and assault course meant that officer cadets had to put on their combat jackets and helmets for safety reasons while on the assault course. This meant they were unable to dissipate heat properly. Both of these problems have now been overcome with a more even physical training programme and the assault course being completed prior to the main run.
A number of cases of EHI occurred during the competition events at the beginning of term 3, which have an element of individual best effort. The same degree of physical exertion may be required during an endurance training period but does not appear to produce heat casualties, possibly this is due to the competition element.
A great deal of useful research has been done into the effect of acclimatisation.25 ,26 Natural acclimatisation reduces the risk of heat casualties when performing military tasks in heat. The training programme at RMAS is graded so that the intensity of exercise is gradually increased over several weeks. Cases are occasionally seen early in the programme, which may represent poor physical adaptation or a lower level of basic fitness.22 Officer cadets are sent an information pack prior to the commissioning course advising them what level of fitness is required.
Body armour and Nuclear, Biological and Chemical clothing are well known to reduce the individual’s ability to thermoregulate. They are not worn during any endurance training at RMAS. Most RMAS events take place in lightweight trousers and T-shirts. The exception to this is the assault course, which must be done wearing helmets and combat clothing with sleeves.
Kerstein et al 27 determined the value of intensive education on the number of heat casualties taking part in a very large (n=6010) Combined Arms Exercise in California in open desert conditions. They concluded that awareness of the problem and enforced work/rest cycles and drinking policy does reduce the incidence of EHI. Other studies have supported this finding.13 Bricknell3 noted that the presentation of education to Platoon Commanders and medical officers has not been well studied. Military doctors need particular education themselves in order that they might give authoritative advice to Unit Commanders. At RMAS the Platoon Commanders and officer cadets all receive lectures about heat illness from the PT staff, Senior Medical Officer and Specialist Advisor from the Institute of Naval Medicine.
Conclusions
EHI is a clinical diagnosis based on the measurement of physical parameters and comparison with reference ranges for a normal population. This study demonstrates that it is very difficult to make an accurate diagnosis of EHI because the military population is not directly comparable to a resting civilian population. In particular CK level and presenting temperature may be misleading. From these cases, it is obvious that the traditional model of overweight, unfit recruits pushed beyond their physical limits does not apply to every case of EHI and certainly not to the majority of cases at RMAS. Under diagnosis of heat illness endangers officer cadets by not warning them that they are at risk of further and possibly more severe episodes. Over diagnosis results in the medical discharge of fit officer cadets or at the very least a 3 month delay in their careers. They are also made aware that a second episode would enforce their discharge from the services, which could lead to non-declaration of early symptoms with potentially disastrous consequences. A model is required to predict who is in danger of becoming a heat casualty. This model could be produced at RMAS by studying core temperature while exercising, preexercise and postexercise CK levels and blood pressure. BMI and BFT should be measured on entry and at the time of the event to assess changes in fitness and obesity. Risk assessment is carried out continuously at RMAS. Where an activity causing EHI has been identified the training programme has been adapted and continues to be closely monitored. RMAS takes its responsibility to officer cadets very seriously. The number of cases initially treated as EHI was an overestimate of the true number of cases but in this way the Academy and medical services were protecting the lives of officer cadets entrusted to their care.
Acknowledgments
I would like to acknowledge the help of Lt Gen (Retd) MCM Bricknell CB QHP, who in 2001 was CO 22 Field Hospital in the preparation of this manuscript and obtaining reference material and thank Col JE Burgess, Lt Col RF Cordell, and Col(Retd) J Owen for their assistance.
References
Footnotes
Twitter @icemaidennat
Contributors AE wrote the paper in 2000 and NT only edited for publication in 2020.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval It is a review of lessons learnt from EHI at RMAS in 1990s.
Provenance and peer review Not commissioned; internally peer reviewed.
Author note This paper was originally written as an internal military report in 2000 and has now been published verbatim as a footnote and endpiece as it fills an important gap in the exertional heat illness (EHI) literature, while demonstrating that the British Army can be progressive in its approach to training and is committed to organisational learning. Its publication offers opportunity to disseminate best practice beyond RMAS, which continues to model this in respect of prevention, detection and treatment of the inevitable – but potentially much reduced – incidence of EHI in military personnel. Publication was not possible when the work was conducted because of barriers within RMAS at the time. However, this paper demonstrates the learning culture with RMAS and this has been recognised with authority to publish 20 years later.