A warming system, mounted to the foot of a bed, warms a person's lower extremities by directing air into the space between the mattress and overlaying blankets. A blower directs air into an elongated distribution chamber having many tiny exit apertures. The chamber is mounted at the foot of the bed, so that air exiting the apertures warms the person's feet. For maximum thermal transfer, the chamber is placed under the sheet and any blankets, but above the mattress cover and fitted sheet. The chamber may be implemented by a length of open cell foam, a hollow manifold with many punctures or other tiny distribution apertures, collapsible pocket, etc. While the person is lying on the bed beneath the blankets, with feet proximate the foot of the bed, the blower directs temperature-regulated air into the chamber and through the exit apertures, thereby warming the person's feet. A temperature regulator ensures a normothermic air temperature (or alternatively, hyperthermic air temperature.) Thus, the invention helps relieve or prevent "cold feet" by directing normothermic air at a person's lower extremities. Additionally, by applying heat to the feet and legs, the invention encourages blood flow by virtue of sympathetic vasodilation and local temperature-mediated vasodilation. The invention is also believed to prevent some leg and foot ulcers from forming by maintaining the lower extremity at a near normal temperature during sleep.