I take my hbp meds one hour before a moderate paced walk in the hot early morning in florida. although i am hydrated i feel somewhat lightheaded. why?

Get a check up: There could be change in blood pressure and heart rate, from sitting to standing position. This is called "orthostatic hypotension". Please consult your doctor to get the correct diagnosis.

Circulation: The medications affect your blood circulation and pulse rate. You could be feeling lightheaded because of the medicines since effects. Always be careful so you don't pass out and hurt yourself. Check your blood pressure before and after you exercise and see your doctor this week to determine the proper cause.

Difficult to say: The cause(s) of your lightheartedness may be due to a variety of issues unrelated to your walking. See a primary care physician for evaluation. I recommend dr. Sara levine in boca raton at 561-750-2338.