Sleep Glossary

SLEEP GLOSSARY

• Circadian rhythm – The internal clock that your body follows during a 24-hour period, moving between alertness and rest in response to changes in light. Circadian rhythms regulate eating habits and other behaviors and bodily functions, in addition to the cycle of sleeping and waking.
• Parasomnia – Disruptive events or behaviors that interfere with restful sleep. These may include sleepwalking, talking during sleep, sleep-related eating disorders, sleep paralysis or intense and vivid nightmares called night terrors.
• Microsleep – A temporary episode of sleep lasting for a few seconds, followed by a swift return to wakefulness. This is sometimes referred to as "nodding off," and is most likely to occur after sleep deprivation. Microsleeping can be dangerous if it takes place during certain activities, such as driving or operating heavy machinery.
• Sleep debt – The difference between the amount of quality sleep that one requires in order to feel well-rested, and the amount of sleep one actually gets. Accumulated, chronic sleep debt can have lasting health impacts, even after the person "catches up" on their missed sleep.