Continuous vs. intermittent work with Canadian Forces NBC clothing

Area of Science:

• Environmental Physiology
• Military Science
• Occupational Health

Background:

• Soldiers often operate in demanding environments requiring protective clothing.
• Nuclear, Biological, and Chemical (NBC) defense suits significantly increase physiological strain.
• Understanding work tolerance under these conditions is crucial for mission effectiveness.

Purpose of the Study:

• To evaluate the impact of work and rest schedules on soldiers' work tolerance time (WTT).
• To assess WTT across different levels of NBC protective clothing in a warm environment.
• To establish relationships between metabolic rate and WTT for optimized work/rest protocols.

Main Methods:

• Eight unacclimatized males performed light or heavy metabolic rate exercises.
• Subjects wore three levels of NBC protective clothing: combat (L), combat + overgarment (M), and full NBC gear (H).
• Work tolerance was measured under continuous and intermittent work/rest protocols until physiological limits or 5 hours.

Main Results:

• Intermittent work and rest schedules demonstrated benefits for work tolerance compared to continuous exercise.
• A hyperbolic function effectively described the relationship between WTT and metabolic rate for medium (M) and heavy (H) protection levels.
• Physiological strain, indicated by rectal temperature and heart rate, limited WTT.

Conclusions:

• Work and rest schedules are critical for enhancing soldiers' performance and safety in NBC protective gear.
• The quantified hyperbolic relationship allows for the prediction of suitable work and rest durations based on task demands.
• This research provides a basis for developing evidence-based operational guidelines for soldiers in hazardous environments.