How much sleep do you actually need?
The NHS aligns with the international consensus: most adults need 7-9 hours per night. Yet The Sleep Council's Great British Bedtime Report found UK adults average just 6 hours 48 minutes on weeknights, well below the lower bound. That gap of over an hour per night adds up to a deficit of more than 7 hours by the weekend.
Sleep recommendations by age (NHS / NSF consensus)
| Age group | Recommended hours |
|---|---|
| Newborn (0-3 months) | 14-17 hours |
| Infant (4-11 months) | 12-15 hours |
| Toddler (1-2 years) | 11-14 hours |
| Pre-school (3-5) | 10-13 hours |
| School age (6-13) | 9-11 hours |
| Teen (14-17) | 8-10 hours |
| Adult (18-64) | 7-9 hours |
| Older adult (65+) | 7-8 hours |
Social jetlag: the hidden sleep thief
Social jetlag describes the mismatch between your internal body clock and the hours imposed by work schedules. On free days, most people sleep roughly 2 hours later than on work days. This chronic misalignment, like flying weekly between London and Reykjavik, is associated with higher rates of metabolic syndrome, depression, and cardiovascular disease. The term was coined in 2006 by chronobiologist Till Roenneberg at LMU Munich.
Melatonin in the UK: prescription only
Unlike the United States, where melatonin is sold freely as a food supplement, the UK classifies melatonin as a prescription-only medicine. Circadin (2 mg modified-release) is licensed for adults aged 55 and over to treat primary insomnia. Obtaining it without a prescription is not legal in the UK. This matters when comparing advice from US-sourced health content with UK clinical practice.
Seasonal light and sleep at UK latitudes
The UK sits between 50°N and 61°N. In midwinter, London gets around 8 hours of daylight while Edinburgh gets under 7. This shortfall in morning light delays the release of cortisol and shifts the internal clock later, making it harder to fall asleep at a consistent hour. In summer the opposite happens: light from 4:30 AM can suppress melatonin prematurely. Blackout curtains and consistent wake times matter more in Britain than in countries closer to the equator.
Sleep cycles and optimal wake times
Sleep progresses through approximately 90-minute cycles, each containing light sleep, deep sleep, and REM stages. Waking at the end of a complete cycle, rather than mid-cycle during deep sleep, tends to feel far less groggy. For a 7:00 AM wake time, aim to fall asleep around 11:30 PM (5 cycles, 7.5 hours) or 10:00 PM (6 cycles, 9 hours). Factor in roughly 15 minutes to fall asleep when calculating your bedtime.
Can you catch up at the weekend?
Research published in 2019 in Current Biology (Depner et al.) showed that weekend recovery sleep does not fully reverse the metabolic damage caused by a week of short sleep. Participants who "caught up" at weekends still showed impaired insulin sensitivity compared to those who slept consistently. Short-term cognitive deficits do improve with recovery sleep, but habitual debt carries a cumulative cost. The NHS recommends addressing sleep quantity every night rather than relying on weekend lie-ins.
Sources: NHS, The Sleep Council Great British Bedtime Report, Roenneberg et al. 2006 (Current Biology), Depner et al. 2019 (Current Biology). This tool provides general information only and does not constitute medical advice.