title: Continuous vs. intermittent work with Canadian Forces NBC clothing.
abstract: This study examined the benefits of work and rest schedules on soldiers' work tolerance (WTT) while wearing various levels of nuclear, biological and chemical (NBC) defence protective clothing in a warm environment (30 degrees C and 50% R.H.). Eight unacclimatized males were assigned to exercise at either a light (walking 1.11 m.s-1 0% grade, alternating with lifting 10 kg) or heavy metabolic rate (walking 1.33 m.s-1 7.5% grade, alternating with lifting 20 kg). Subjects were tested wearing three levels of clothing protection: combat clothing (L); combats and a semi-permeable NBC overgarment with the hood down (M); combats and NBC overgarment, gloves, boots and respirator (H). For each clothing configuration, subjects were evaluated using both a "continuous" exercise protocol and an intermittent work and rest schedule. WTT was defined as the time until rectal temperature (Tre) reached 39.3 degrees C, heart rate reached 95% maximum, dizziness or nausea precluded further exercise, or 5 h had elapsed. Assuming a resting VO2 of 4 ml.kg-1 x min-1 an average metabolic rate was calculated for all trials. A decreasing hyperbolic function described the relationship between WTT and metabolic rate for M and H. These relationships facilitate quantification of appropriate work and rest schedules if the metabolic rate of a task is known.
authors.affiliation: Defence and Civil Institute of Environmental Medicine, North York, Ontario, Canada.
authors.forename: T M
authors.initials: TM
authors.lastname: McLellan
authors.forename: I
authors.initials: I
authors.lastname: Jacobs
authors.forename: J B
authors.initials: JB
authors.lastname: Bain
mesh_terms: D000328:Adult; D002170:Canada; D004734:Energy Metabolism; D006358:Hot Temperature / Q000009:adverse effects; D006801:Humans; D008297:Male; D008889:Military Personnel; D010101:Oxygen Consumption; D010807:Physical Endurance; D005082:Physical Exertion / Q000502:physiology*; D011481:Protective Clothing; D013312:Stress, Physiological / Q000150:complications