Biofeedback is a method of learning to self-regulate. The simplest form might be holding a thermometer in your hand. Tell yourself to warm your hands and watch the temperature increase. It works! With practice, you can learn to increase the temperature of your hands more and more. You can learn other biofeedback methods such as relaxing to slow your heartbeat. With advanced computer-aided biofeedback learning, you can learn increase or decrease vital physiological conditions.