title: Prolonged physical inactivity leads to a drop in toe skin temperature during local cold stress.
abstract: The purpose was to examine the effects of a prolonged period of recumbency on the toe temperature responses during cold-water foot immersion. Ten healthy males underwent 35 days of horizontal bed rest. The right foot of the subjects was assigned as the experimental (EXP) foot. To prevent bed rest-induced vascular deconditioning in the left control foot (CON), a sub-atmospheric vascular pressure countermeasure regimen was applied on the left lower leg for 4 × 10 min every second day. On the first (BR-1) and the last (BR-35) day of the bed rest, subjects performed two 30 min foot immersion tests in 8 °C water, one with the EXP foot and the other with the CON foot. The tests were conducted in counter-balanced order and separated by at least a 15 min interval. At BR-35, the average skin temperature of the EXP foot was lower than at BR-1 (-0.8 °C; P = 0.05), a drop that was especially pronounced in the big toe (-1.6 °C; P = 0.05). In the CON foot, the average skin temperature decreased by 0.6 °C in BR-35, albeit the reduction was not statistically significant (P = 0.16). Moreover, the pressure countermeasure regimen ameliorated immersion-induced thermal discomfort for the CON foot (P = 0.05). Present findings suggest that severe physical inactivity exaggerates the drop in toe skin temperature during local cold stress, and thus might constitute a potential risk factor for local cold injury.
authors.affiliation: a Department of Environmental Physiology, School of Technology and Health, Royal Institute of Technology, Berzelius väg 13, SE-171 65, Stockholm, Sweden.
authors.forename: Michail E
authors.initials: ME
authors.lastname: Keramidas
authors.forename: Roger
authors.initials: R
authors.lastname: Kölegård
authors.forename: Ola
authors.initials: O
authors.lastname: Eiken
authors.forename: Igor B
authors.initials: IB
authors.lastname: Mekjavic
mesh_terms: D001510:Bed Rest; D003080:Cold Temperature; D058639:Cold-Shock Response / Q000502:physiology*; D006801:Humans; D008297:Male; D012881:Skin Temperature; D013997:Time Factors; D014034:Toes / Q000502:physiology*; D055815:Young Adult