Similar thermal strain reductions and cognitive function with age and air velocity during heat stress

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Proceedings titleMedicine and Science in Sports and Exercise
ConferenceACSM Annual Meeting, May 27-31, 2014, Orlando, Florida
AbstractOlder adults may be at greater risk for occupational injuries given their reduced evaporative heat loss when full sweat evaporation is permitted, leading to greater thermal strain and potentially cognitive decrements. However, age-related differences in heat loss capacity may not be as evident under conditions which restrict evaporative heat loss (i.e., humidity, clothing), subsequently increasing the risk in all workers. Although industries increase air circulation in attempts to reduce thermal strain, the effectiveness in reducing physiological strain and cognitive function impairments are unknown.PURPOSE: To examine the effects of increased air velocity during exercise in humid heat on the capacity and rate of information processing and attention of young versus older adults.METHODS: Nine young (Mean±SE; Y: 24±1 yrs) and 9 older (O: 59±1 yrs) males, matched for body surface area and wearing coveralls, cycled 4 x 15 min (15 min rest) at a fixed rate of heat production (400 W) in humid heat (35°C, 60% relative humidity) under 0.5 (Low) and 3.0 m/s (High) air velocity. Rectal temperature (Tre) and heart rate (HR) were measured continuously. At baseline (PRE), immediately following exercise (POST), and the end of the 30 min final recovery (END), participants performed a Paced Auditory Serial Addition Task (PASAT, 2s).RESULTS: Tre and HR were similar between age groups in Low and High, however were greater in Low (Tre POST: Y = 38.30±0.12, O = 38.31±0.08°C) than High (Tre POST: Y = 37.96±0.09, O = 37.84±0.09°C) for both groups. PASAT # of correct responses was similar between Y (POST: Low = 49±3, High = 51±3) and O (POST: Low = 46±5, High = 47±4) and conditions. When scored relative to age norms, no differences were observed between groups or conditions for z-scores or percentile (Low: Y = 69.0±7.5, O = 69.8±9.7; High: Y = 72.7±6.3, O = 73.0±8.3%).CONCLUSION: Preliminary data indicate that while cognitive decrements in attention and working memory were not observed following intermittent exercise in humid heat or altered air velocity, increased air velocity reduced thermal strain equally in young and older males. This Project was funded by research grants provided by the Workplace Safety and Insurance Board (Ontario), Canada Foundation for Innovation-Leaders Opportunity Fund (G.P. Kenny), MITACS Accelerate (H.E. Wright).
Publication date
PublisherAmerican College of Sports Medicine
AffiliationAerospace; National Research Council Canada
Peer reviewedYes
NPARC number23001344
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Record identifier99883e67-918f-4b43-a89c-e02987d447cb
Record created2017-01-20
Record modified2017-01-20
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