Cardiovascular and Thermal Strain during Manual Work in Cold Weather
NEW BRUNSWICK UNIV FREDERICTON
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In some occupations it is hard to protect the hands against the severe weather conditions in wintertime due to the requirement to maintain manual dexterity. Decrease in temperature of the hands increases risk of cold injury and deteriorates muscle function and manual dexterity, which in turn decreases productivity. A series of field and lab studies were performed to investigate cold stress and cold acclimation on the neuromuscular function of the hand. To quantify the cardiovascular and thermal strain during a working day in cold weather 17.6 3.1 C mean sd, five line workers 4 male, 1 female, 36.4 4.4 y from the maintenance crew of New Brunswick Power were equipped with skin thermistors and heart rate monitors and followed for a day 0900h 1600h. Typical tasks were videotaped and a time log of activities and hand protection levels were recorded. Hand and finger temperature dropped as low as 17.0 24.4 C and 7.9 12.6 C, respectively. Average temperatures over the working day period varied from a hand temperature of 24.8 31.4 C to 21.0 29.8 C for the index finger. The lowest mean body skin temperature ranged from 21.0 29.4 C while on average, this was 25.6 34.1 C. Typical tasks included climbing poles, cutting wires, and shovelling snow. Peak heart rate HR was 148 181 b min-1. Although the measurements took place during a day of relatively mild weather and light activity, skin temperature of fingers and hands decreased to a level that has been previously demonstrated to impair manual dexterity. The intensity level of certain tasks was as high as 82 97 of the age-predicted HRmax. It was concluded that alternating high intensity tasks with low intensity tasks demanding manual dexterity, will decrease cardiovascular strain and may improve manual performance by warming the body and hands.
- Anatomy and Physiology
- Medicine and Medical Research