Sleep & Circadian - Troubleshooting
Fixing the most common sleep problems
Last reviewed 13 August 2026. How we write this .
The mechanisms behind everyday sleep complaints - trouble falling asleep, night waking, jet lag and social jetlag - and what the evidence says about each.
Start here The mechanisms behind everyday sleep complaints - trouble falling asleep, night waking, jet lag and social jetlag - and what the evidence says about each.
By the end, you will understand Trouble falling asleep Waking in the night Jet lag and social jetlag Where this information comes from Claim-cited evidence. Central research claims on this lesson are linked to specific studies or official guidance.
This lesson links the specific studies and guidance used for its central claims.
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Many common sleep difficulties share a small number of underlying causes, most of them tied to timing, arousal or the natural sleep drive. Understanding the mechanism makes it easier to see why the well-supported basics help and why quick fixes often do not.
Trouble falling asleep
Difficulty drifting off is frequently a mismatch between when you try to sleep and when your rhythm is ready, or a state of heightened arousal at bedtime. Bright evening light, late stimulants and an active, stressed mind all push in the same direction. The evidence supports strengthening the day-night light contrast and reducing evening arousal, while sedatives that force sleep tend to be a weaker long-term answer.
Waking in the night
Brief awakenings are a normal part of sleep, and noticing a few is not in itself a sign that something is wrong. Waking that is frequent or hard to recover from is more often linked to factors such as alcohol, a warm room, or worry about the waking itself. Alcohol is a good example of the mechanism-versus-effect gap - it can shorten the time to fall asleep while measurably fragmenting sleep later in the night.
Jet lag and social jetlag
Jet lag is a temporary mismatch between your clock and a new time zone, and it eases as light exposure in the new location gradually re-entrains the rhythm. Social jetlag describes the smaller, recurring mismatch when work-week and weekend schedules differ, effectively shifting your clock back and forth. Regular timing is the lever most consistently linked to reducing it. Across all of these, the pattern is the same: the durable improvements come from supporting the rhythm and the sleep drive, not from overriding them. When simple, well-supported adjustments do not help over time, that persistence is itself worth taking seriously - the subject of the next lesson.
Educational content only, and not a substitute for medical advice or a treatment plan. Persistent sleep problems deserve assessment by a qualified clinician rather than self-management alone.
Related in this classroom The studies behind this page Insomnia: self-care, assessment and treatment - NHSLight modulation of human clocks, wake and sleep - Clocks & Sleep, 2020Sources for this classroom
Educational content only. Not medical advice, diagnosis or treatment. Always consult a qualified healthcare professional before changing your health regimen.