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ABSTRACT
Exposure to cold climate is an inevitable consequence of military training in Norway. Adequate peripheral microcirculation in the extremities is important to maintain temperature, and to protect against freezing cold injuries. The aim of this study was to investigate the variability in skin rewarming ability. The study subjects consisted of 260 healthy Norwegian army conscripts, following a mild cold provocation test (hands immersed in 20°C water for 1 min) using dynamic infrared thermography (DIRT). Thermal images were obtained to investigate any differences in skin rewarming ability of the hand (fingers). DIRT took place under standardised and stable study conditions. Conscripts were characterised as either slow, intermediate or rapid rewarmers. While 90% could recover, partially or completely, within 4 min to the skin temperature values before the provocation test, 10% showed a slow rewarming pattern. In the slow rewarmers, the rewarming ability was correlated with a low average temperature of the hands prior to the cooling test. The healthy young army conscripts in this study showed a large variability in their rewarming ability following a standardised mild cold provocation test.
ARTICLE HISTORY
Received 26 February 2018
Revised 9 August 2018
Accepted 1 October 2018
KEYWORDS
Thermography; soldier; conscript; hand; circulation; cold challenge; nicotine; frostbite; snus
Introduction
More than half of Norway is above the Polar Circle. In the harsh Norwegian climate, the annual number of army conscripts undergoing basic military winter training is approximately 7,500. People in the northern part of the country, and especially in the inland areas, are exposed to winter conditions with temperatures often reaching -40°C. The incidence of cold injuries among soldiers during winter service in the northern part of Scandinavia has been reported to be around 2% per year [1,2].
Since exposure to cold climate is an inevitable consequence of military training, there is a need for increased focus on prevention and risk factor identification for cold injuries in soldiers [3]. However, there are no evidence-based techniques for identifying individual risk factors for susceptibility to cold injuries [4]. Skinsurface temperature is highly dependent on blood circulation in the outer millimetres of the skin, which is controlled by a complex autonomic regulatory system as well as local factors. There are although research findings underpinning the fact that nerve function governing...