Effects of Lightweight Outdoor Clothing on the Prevention of Hypothermia During Low-Intensity Exercise in the Cold

OBJECTIVE: To study protective effects of windbreaker jacket and pants during exercise in the cold. DESIGN: Randomized pilot study. SETTING: Climate chamber. PARTICIPANTS: Nine well-trained (V[Combining Dot Above]O2max 61.7 ± 6.6 mL/min/kg) sport students (6 male and 3 female participants). INTERVENTIONS: Subjects started walking for 1 hour in a climate chamber (0°C ambient temperature and wind speed of 10 km/h) at 70% V[Combining Dot Above]O2max wearing gloves, a T-shirt, and shorts. Then, the walking speed was reduced to 30% V[Combining Dot Above]O2max for an additional 60 minutes or until core temperature dropped below 35.5°C. Subsequently, 3 groups of 3 participants continued walking without change of clothing or obtaining additionally a cap and a windbreaker jacket or windbreaker jacket and pants. MAIN OUTCOME MEASURES: Core and skin temperature, thermal comfort. RESULTS: The main findings of this study were that exercising at 70% V[Combining Dot Above]O2max in the cold was sufficient to prevent hypothermia and that during low-intensity exercise (30% V[Combining Dot Above]O2max), the combined use of a polyester cap, lightweight windbreaker jacket, and pants was necessary to increase a prehypothermic core temperature. CONCLUSIONS: We strongly recommend taking a cap, windbreaker jacket, and pants for the prevention of hypothermia during exhaustive walking or running in cold weather conditions.