DEEP DIVE 1. How long do we really need to sleep?
Key takeaways
• Habitual sleep duration under 7 hours is robustly associated with worse outcomes across metabolic, cardiovascular, immune, cognitive, and mental health domains.
• Short sleep disrupts appetite-regulating hormones, reducing insulin sensitivity and increasing risk of type 2 diabetes and obesity.
• Cardiovascular risk is elevated by chronically short or fragmented sleep, via sustained blood pressure elevation and increased systemic inflammation.
• Sleep plays an active role in immune defence and vaccine response; short sleepers are more susceptible to infection.
• The brain’s glymphatic waste-clearance system operates primarily during sleep; chronic sleep insufficiency may impair clearance of proteins associated with Alzheimer’s disease.
• Chronic insomnia is bidirectionally linked with depression and anxiety; CBT-I is the NICE-recommended first-line treatment.
• Effects are systemic and cumulative. Sleep is most usefully treated as a health behaviour on a par with diet and exercise, not as a passive default state.
Sleep well 1 - How much sleep do we really need?
Most healthy adults need between 7 and 9 hours of sleep a night. That is not a suggestion or a lifestyle preference — it is what the evidence consistently shows, backed by sleep researchers and medical bodies around the world. Yet a significant number of people are regularly getting less, and most of them think they’re coping fine. This post looks at what sleep actually does for you, what happens when you cut it short, how to find your own personal sweet spot, and a few simple changes that make better sleep more likely — without requiring you to become a different person.
Sleep Well - Pillar 1 of the New 5-a-day
Sleep Well is Pillar 1 of the New 5-a-day because we believe good sleep is the foundation for feeling good and living our best lives.