Wool in outdoor clothing systems is stated to be a good temperature and humidity regulator giving the wearer a warm and dry feeling during physical activities in the cold. The objective was to compare two different battings (sheep wool ''tirolwool'' (TW) versus polyester microfiber (PMF)) in an outdoor jacket of a two-layer outdoor clothing system consisting of a shirt and jacket on the heat and moisture management and comfort sensation during a moderate mountain walking protocol which was followed by a cool-down phase in the cold (À5 C, 43% relative humidity). Due to its beneficial moisture management properties it was hypothesized that TW in the outermost layer would cause a higher skin and core temperature, reduce the after chill effect, increase moisture transfer, decrease moisture accumulation within the clothing system, and lead to more pleasant comfort sensations. Twelve sport students performed the simulated walking protocol (60 min, 7.7% inclination, 5 km/h) and cool-down phase (20 min) with TW and PMF in a climatic chamber. The use of TW compared to PMF was stronger moisture absorbent led to a dryer shirt (p ¼ 0.043) and lower humidity underneath the shirt and jacket (chest: p 0.05). Core temperature (p ¼ 0.017) and skin temperature drop (chest: p ¼ 0.003) were attenuated with TW after the physical activity. Therefore, the after chill effect was reduced with TW but moisture accumulated to a higher extent in the jacket (p ¼ 0.001), which might lead to a longer drying rate. Correlation analysis revealed that tested underwear blended with merino wool, elastane, and polyamide might feel less scratchy in the slightly damp state than in the dry state.