Abstract: Temperature sensors are configured to sense a temperature for the sleeper and transmit temperature readings. A controller is configured to receive temperature readings; and send to a heating subsystem instructions to initiate a warming process that raises a distal temperature of the sleeper more than a proximal temperature of the sleeper. The heating subsystem that may include a heating element that, when engaged, can raise the distal temperature of the sleeper more than the proximal temperature of the sleeper.

Abstract: A distal-proximal temperature-gradient of a sleeper is determined. A bed has a mattress. Temperature sensors are in an array. Each sensor is configured to: sense surface temperature of the sleeper of the bed, transmit, to a controller, temperature readings. The system also includes a controller may include a processor and memory, the controller configured to: receive, from each of the sensors, temperature readings at a particular time, access, for each temperature reading, a corresponding weight-value, determine the distal-proximal temperature-gradient for the sleeper at the particular time using the temperature readings and the corresponding weight-values.