Previous reports indicate that everyday excursional exposures may play a part in increased winter mortality (Donaldson et al 1997) and that the avoidance of cold stress is associated with low indices of cold related mortality in Europe (Eurowinter Group 1997). However, few prospective data have been reported on excursional data and risk factors for arterial disease. In a field study carried out on 21 young (mean age 23.5) and 24 elderly healthy subjects (mean age 73.6) there were no significant differences between winter and summer in the number or duration of outside excursions. Never the less, elderly subjects had significantly more clothing insulation (clo), both indoors and outdoors in the winter than in the summer (p < or = 0.001) and this was also the case for young subjects. The urine temperature of the elderly in the winter was significantly lower (p < or = 0.01) than in the summer but this was not seen in the young. Elderly physical activity was significantly higher in the winter than in the summer (p < or = 0.05) but not for the young. Thus, elderly subjects showed no material change in excursional behaviour in the winter, even though clothing protection was arguably inadequate in view of lower body temperature, accompanied by increased physical activity. Blood pressure was significantly higher in the winter (p < or = 0.01) in the elderly, though the extent to which activity levels contributed to this contrast is uncertain from these data.