I just turned 74, and am "well-preserved" for my age. I go on daily brisk walks of about an hour's duration, and climb at least five flights of stairs a day. Several months ago, I added moderate hill climbing twice a week. However, I have noticed that my leg muscles (quads, hamstrings, calves) are not "getting used" to this exercise, and ache somewhat during the level walks, moreso on slight inclines, and fairly strongly on the hill climb (which I've given up temporarily). My BMI is 26 (only slightly overweight). I do not have arthritis in my hips, knees, or ankles. I do not have diabetes. I can still jog/run short distances. My doctor hasn't been much help so far with this problem. I am wondering what the possible causes might be, and if they could be related either to nutritional gaps or my current medications (for enlarged prostate, mild COPD, and high BP and cholesterol tendencies - the latter two are under control).