Biometrological assessment of skin protectors against moderate cold threat.

Background : Cold injuries represent a serious problem in winter sport practice and other outdoor activities. Some protection is expected to be achieved by specific topical preparations aiming at decreasing heat loss by water evaporation from the skin. Objective : To compare the efficacy of 6 topical formulations enriched or not in rubefacients. The role of the vehicle was also assessed. Methods : A total of 30 trained cyclists tested the products on their forearms. The skin temperature and electrometric values were recorded at baseline following applications of the test products, and after 30 min-bicycle riding in moderately cold and humid outdoor conditions. Results : At baseline, skin temperature was increased by rubefacients dispersed a lipogel and o/w emulsion. This parameter decreased at all test sites after riding, but the values remained higher at the rubefacient-treated sites compared to the control untreated site. The oil and lipogel formulations achieved partial occlusion decreasing the transepidermal water loss. This effect was maintained after exercise without, however, hindering sweating. Conclusion : Among the presently tested formulations, the rubefacient-enriched lipogels appeared to be the most efficient formulations for maintaining skin temperature in the normal range during sport practice in a moderately cold environment.