I Am 65 And Walk Two Miles Nearly Every Day--early

I am 65 and walk two miles nearly every day--early morning in the summer and afternoon in the winter, yet I often feel cold by two in the afternoon and again by eight in the evening. I have an occasional ache on the right side of my throat, but never on the left side. Having been struck by a car 43 years ago in Europe which resulted in a six-month long hospitalization, I ignore small aches and pains. I am 5'6'' and now weigh 160 pounds: my immediate family were all considerably overweight. Why do I get cold every afternoon or night? I keep the temperature of my house at 76 during warm weather.