Circadian Health Glossary
Phase Delay
Phase delay refers to a shift in the timing of the body’s circadian rhythms to a later point in the 24-hour cycle. This means activities such as falling asleep, waking up, or hormone production occur later than usual. Phase delays are commonly associated with night owls or those who naturally prefer late-night activity and later wake times.
What Causes a Phase Delay?
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Light Exposure: Exposure to light, especially blue light, in the evening can push the circadian clock later.
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Lifestyle Habits: Late-night screen time, irregular schedules, or caffeine consumption in the evening can contribute to phase delays.
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Age: Adolescents often experience natural phase delays due to biological changes during puberty.
Why Is Phase Delay Important?
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Circadian Health: Phase delays can disrupt daily routines, leading to sleep deprivation or misalignment with societal schedules.
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Light Therapy: Morning light therapy can help counteract a phase delay, shifting the circadian rhythm earlier to improve sleep and wake timing.
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Sleep Disorders: Phase delay is a key feature of Delayed Sleep Phase Disorder (DSPD), a condition where individuals struggle to fall asleep and wake up at conventional times.