Are young military personnel at a disproportional risk of heat illness?

Heat illnesses (HI) define a continuum of conditions where patients become incapacitated due to uncompensable heat stress. In the military, HI has a significant health, financial and operational burden that requires vigilant management. Military training and operations regularly expose personnel to known HI risk factors, meaning that prevalence remains high despite stringent attempts to reduce risk to as low as reasonably practicable. While prepubertal children and elderly adults are widely demonstrated to be at greater risk of classic HI than young adults due to impaired physiological and/or behavioural thermoregulation, in military personnel, it is young recruit-age individuals (16-19 years) who consistently experience the highest prevalence of exertional HI. Mechanistically, controlled laboratory studies have never directly compared thermoregulation between young recruit-age individuals and other groups of adults, though research highlighting impaired thermoregulation in prepubertal children potentially has some relevance to late-developing young recruit-age personnel. Aside from potential age-related differences in thermoregulation, a major consideration must also be given to the increased prevalence of organisational risk factors for HI in younger military personnel (eg, education, physical load, rank, job roles), which is likely to be the primary explanation behind age-related trends in HI prevalence, at least in the military. The aims of this article are to review: (i) the epidemiology of HI between young recruit-age individuals and older military personnel; (ii) the theoretical basis for age-associated differences in thermoregulatory function and (iii) pertinent areas for future research.

On the real-time prevention and monitoring of exertional heat illness in military personnel

The proliferation of user-friendly low-cost wearable sensors has brought the concept of real-time physiological monitoring for exertional heat illness to the cusp of reality. This paper reviews and discusses the current state of the art in real-time physiological status monitoring for exertional heat illness mitigation within the military context. The review examines how both advanced sensor systems, models and algorithms are being combined in an international and collaborative way and how this is providing real solutions to military units to reduce the risk held by the commander. This paper provides additional detail into the process of integrating physiological status monitoring into military training, it explores the development of on-body sensors, the algorithms that can provide actionable information, the process of planning and dynamic risk assessment and describes some of the physiological monitoring systems that are currently being developed by the representative nations. It then discusses the knowledge gaps of how the technology will be integrated into military training, the importance of meaningful, accurate information that is both sensitive and specific and further developing the accuracy of the algorithms and models that are being employed. Finally, it talks about future direction and how individualizing physiological status monitoring can lead to performance enhancement in the form of individualized heat acclimatization programs. In conclusion, physiological status monitoring is at a stage of transition and integration where it can be used effectively to manage and reduce exertional heat illness to enable military personnel to train hard-train safe.

Nutrition research in the military

Military research performed in an operational environment involves mission-specific considerations. The Institute of Naval Medicine was tasked in 2008 by the Surgeon General to investigate the nutritional status of deployed British military personnel, and how this might affect body composition, physical fitness and operational capability. This paper briefly describes the logistic and technical issues specific to military research that were encountered by the study team, how these issues were overcome and how this research has influenced military practice.