In a house where the temp is 68f and while wearing a tshirt and shorts, what would cause the lower half of your body to feel hot and the upper half of your body to feel cold?

May be adipose : It may be due to variations in the distribution of adipose tissue in the lower vs. upper half of the body. Have a healthy diet, exercise 30 minutes/day, drink plenty of water daily so your urine is mostly colorless, have safe sex, no tobacco alcohol weed or street drugs. For nutrition: http://www.choosemyplate.gov/. Wish you good health!