We conducted a field survey to determine the effects of behavioral patterns and activity level on the thermal comfort of healthy elderly persons living independently during the winter of 1985-1986. One hundred and one subjects of good health from Hamilton, Ontario participated in the study. The mean clothing insulation was 0.8 clo and was virtually constant. The subjects scored 83.5 on the Self-Evaluation of Life Function (SELF) Scale and did not differ significantly from a reference group of healthy elderly subjects from Miami, Florida. The mean activity level at rest was 1.5 met and during periods of light exercise (walking at 1.3 mph, 2 km hr ) and light domestic household work was 1.9 met