I am a 44 yo white female (5'4" and 125 lbs) and occasionally feel light headed following jogging at moderate pace. I workout regularly and would be considered quite fit by most any standard. What might cause this? Earlier today following a jog/ walk of 3+ miles,I felt light headed. A friend checked my BP and I was found to be 89/64. Over the previous 12 hrs I had consumed approximate 1 cup of milk in total.