Heat Strain in Cold

Abstract

In spite of increased environmental cold stress, heat strain is possible also in a cold environment. The body heat balance depends on three factors: environmental thermal conditions, metabolic heat production and thermal insulation of clothing and other protective garments. As physical exercise may increase metabolic heat production from rest values by ten times or even more, the required thermal insulation of clothing may vary accordingly. However, in most outdoor work, and often in indoor cold work, too, the thermal insulation of clothing is impractical, difficult or impossible to adjust according to the changes in physical activity. This is especially true with whole body covering garments like chemical protective clothing. As a result of this imbalance, heat strain may develop. In cold all the signs of heat strain (core temperature above 38°C, warm or hot thermal sensations, increased cutaneous circulation and sweating) may not be present at the same time. Heat strain in cold may be whole body heat strain or related only to torso or core temperature. Together with heat strain in torso or body core, there can be at the same time even cold strain in peripheral parts and/or superficial layers of the body. In cold environment both the preservation of insulation and facilitation of heat loss are important. Development of clothing design is still needed to allow easy adjustments of thermal insulation.

Hypothermia following exertional heat stroke treatment

“…This case emphasizes that EHS can occur even under cold climate conditions, as was previously described (Budd et al 1986;Rintamaki and Rissanen 2006).…”

“…Metabolic heat production is composed of basal metabolism and of regulated heat production by muscular work (either by physical activity or cooling induced shivering). Since most of the heat gain originates from metabolic heat, EHS can occur even in a cold climate, while performing physical activity, especially when wearing insulated clothing and while carrying risk factors (e.g., taking medication, illnesses, dehydration (Rintamaki and Rissanen 2006).…”

Mathematical modeling and numerical simulation of heat and moisture transfer in a porous textile medium

“…The moisture accumulation due to adsorption and condensation within clothing will cause "chilling" discomfort or even hypothermia (e.g. Goldman, 1974;Rintamäki & Rissanen, 2006). For example, workmen who operate in cold environment are subject to fluctuant conditions (e.g.…”

Memantine Prevents Cardiomyocytes Nuclear Size Reduction in the Left Ventricle of Rats Exposed to Cold Stress

“…Reduced body temperature induced by exposure to a cold surrounding environment is considered a physiological stressor 1–3. Neurogenic lesions related to myocardial hypertrophy and changes in myocardial tissue metabolism4 can be also caused by the reaction of cardiovascular tissue to cold stress, and these lesions are hypothesized to be a marker for subsequent cardiovascular disease as well as a predictor of hypertension 5.…”