Overview
- A peer-reviewed study published this week reported that about 23% of people with a history of depression show a likely ‘circadian’ subtype marked by evening preference, morning tiredness, oversleeping and seasonal mood shifts.
- The autumn clock change has immediate effects on sleep timing and alertness, producing earlier sleepiness, stronger afternoon energy slumps and brief shifts in morning wakefulness for many people.
- Experts advise simple, short-term steps after the clocks change: get outdoor daylight soon after waking, keep a consistent wake time, dim evening lighting, exercise in daylight hours and move caffeine consumption earlier in the day.
- The brain’s suprachiasmatic nucleus uses light to set 24-hour rhythms, so bright evening light can suppress melatonin and delay the clock while morning daylight boosts alertness and serotonin.
- Most people readjust within days to about a week, persistent problems merit clinical assessment, and researchers say the new circadian finding could eventually help personalise treatments such as timing of light therapy or medication.