effects. Research simulating increase of light at dawn was shown to potentiate the cortisol awakening response (CAR). The CAR is a spike in blood cortisol levels following awakening, and is associated with the return to an alert cognitive state. Other Some other interventions that could potentially minimize the effects of sleep inertia are sound and temperature. There is moderate evidence that the presence of mild sounds and a sharp decrease in the temperature of the extremities may independently reverse sleep inertia symptoms. Noise, especially music, is thought to increase attentiveness and decrease one's subjective feeling of sleepiness upon awakening. A drop in temperature of the extremities may prevent heat loss upon awakening, facilitating the return of core body temperature to homeostatic daytime levels. See also Circadian rhythm sleep disorder Delayed sleep phase syndrome Shift work Sleep deprivation References External links Flying Safely Article on Napping Sleep Sleep physiology Circadian rhythm