Under stress, Muscles tense, breathing is shallow and hands and feet cool down. Hand and foot temperature can change Over 40° from a low of 60° to a high of 99°F changes of 5° can take place in seconds. To relax, test temperature, close eyes, breathe deeply and slowly, then release tension from every major part of the body, feet first. Next, imagine flooding the body and hands with sunshine. Test temperature again. Heating hands until blue color shows is a sign of relaxation. The black color is low temperature, which shows stress.