Sleep is the bedrock of healthy ageing

The 7 to 8 hour sweet spot

Most people view sleep as a passive luxury, but a systematic review published in Clinical Gerontologist (Ravyts & Dzierzewski) proves it is a primary driver of "successful ageing." By analysing 14 major studies across four continents, the researchers found that sleep is the common thread connecting the three pillars of late-life health: physical health, cognitive sharpness and active social engagement.

The U-shaped rule of longevity

The most critical finding of the review is the "U-shaped" relationship between sleep duration and healthy ageing. The research suggests that longevity isn't about sleeping as much as possible; it is about finding the biological "sweet spot."

• The target: Seniors who consistently sleep 7 to 8 hours per night have the highest likelihood of maintaining independence and high cognitive scores.

• The risk zones: Sleeping too little (<6 hours) or too much (>9 hours) is statistically linked to chronic disease, increased inflammation and functional decline. Short sleep often predicts cognitive impairment, while excessively long sleep can be a marker for underlying cardiovascular issues.

Quality over quantity

The research highlights that "how well" you sleep is often more important than "how long." The review identified that successful agers those who maintain high levels of well-being into their 80s and 90s possess a unique sleep stability.

While many older adults experience fragmented sleep or insomnia, those who age healthily show a resistance to this sleep decay. They maintain better sleep efficiency (the ratio of time spent asleep to time spent in bed). Furthermore, the study links poor sleep quality directly to decreased social engagement. When sleep is poor, seniors are less likely to participate in the social and productive activities that keep the mind sharp.

Redefining successful ageing

The study utilizes the Rowe and Kahn Tripartite Model, which defines healthy ageing as more than just the absence of disease. It requires:

1. Low risk of disease and related disability.

2. High mental and physical function.

3. Active engagement with life.

The review concludes that sleep health is a modifiable behaviour. Unlike genetics, sleep is something we can intervene upon. Identifying and treating sleep disorders like apnoea or insomnia early can delay the onset of disability and promote physical and psychological resilience.

The Sleep Health Checklist

Based on the parameters for "successful agers" identified in the review, use this checklist to evaluate your current sleep health:

• Duration: Do you consistently achieve between 7 and 8 hours of actual sleep?

• Efficiency: Do you fall asleep within 30 minutes of getting into bed and stay asleep for the majority of the night?

• Alertness: Do you feel restored upon waking and remain alert throughout the day without excessive napping?

• Stability: Do you go to bed and wake up at roughly the same time every day, including weekends?

• Symptom Check: Are you free from loud snoring, gasping, or frequent leg movements that disrupt your rest?

• Social Drive: Do you feel motivated to engage in social activities during the day (a key indicator of high-quality nocturnal rest)?