Heat Intolerance, Body Size, and Return to Duty

Area of Science:

• Sports Medicine
• Military Health
• Environmental Physiology

Background:

• Exertional heatstroke impacts athletes and soldiers, potentially causing temporary heat intolerance.
• The heat tolerance test (HTT) aids in military return-to-duty decisions.
• Failure of the HTT can prevent soldiers from serving in combat units, irrespective of the cause.

Observation:

• A 19-year-old soldier collapsed during training with a rectal temperature of 38.7°C.
• He experienced exhaustion during subsequent training and was referred for HTT.
• The soldier failed two HTTs, leading to his discharge from his infantry unit.

Findings:

• No underlying congenital or functional causes were identified for the soldier's heat intolerance.
• The soldier's anthropometric measures, particularly a low body surface area to body weight ratio, are proposed as the cause of the positive HTTs.
• The study questions the safety of returning this soldier to duty.

Implications:

• This case highlights the potential influence of anthropometrics on heat tolerance testing outcomes.
• It raises questions about the universal application of HTT in military return-to-duty decisions.
• Further research is needed to refine heat intolerance assessment in military personnel.