8/22/2026
This is the ninth piece in my series about Eric Topol's book, Super Agers: An Evidence-Based Approach to Longevity. This section focuses on sleep.
1. Sleep is essential to healthy aging
Sleep is a fundamental biological requirement, regulated by our circadian rhythm and the body's central biological clock.
Poor sleep is associated with a remarkably wide range of health problems, including cardiovascular disease, cancer, diabetes, obesity, impaired immunity, Alzheimer's disease, stroke, and mental-health problems.
Topol cites several striking findings:
Sleeping fewer than six hours at ages 50–60 was associated with a 30% higher risk of dementia.
Sleep deprivation triggers harmful inflammatory changes throughout the body.
The loss of one hour of sleep associated with the spring daylight-saving-time change has been linked to a temporary increase in heart attacks.
Improving sleep in people who normally sleep too little reduced their daily calorie intake by about 270 calories.
Greater irregularity in sleep schedules is also associated with higher mortality.
2. One of sleep's most important biological functions: cleaning the brain
One of the most fascinating points in the chapter is the role of the glymphatic system.
During sleep, particularly deep non-REM sleep, cerebrospinal fluid moves through the brain and helps clear metabolic waste.
Even one night of sleep deprivation can impair this waste-clearance process and increase beta-amyloid levels, a protein associated with Alzheimer's disease.
In other words, sleep is not simply a period of rest. The brain is doing important maintenance work while we sleep.
3. About seven hours appears to be just right
Topol discusses large studies suggesting that roughly seven hours of sleep per night is associated with the best health outcomes.
Both too little and too much sleep are associated with increased risk.
In one large analysis:
Each hour below the seven-to-eight-hour range was associated with about a 6% higher cardiovascular risk.
Each hour above that range was associated with about a 12% higher cardiovascular risk.
Long sleep was also associated with higher all-cause mortality and poorer cognitive and mental-health outcomes.
4. Regularity matters
Topol discusses the sleep regularity index and notes that people with more regular sleep schedules had lower mortality.
His advice is: try to maintain roughly the same sleep schedule every day, including weekends.
It is not only how long you sleep, but also how consistently you sleep.
5. Aging makes good sleep more difficult
Unfortunately, sleep becomes increasingly important as we age.
Older adults tend to experience:
less deep sleep
more fragmented sleep
lower sleep efficiency
earlier bedtimes
earlier awakenings
changes in circadian timing.
That makes protecting sleep especially important in later life.
6. America has a widespread sleep deficiency
Topol points out that roughly 35–40% of American adults regularly sleep fewer than seven hours a night.
Americans also rank among the populations with the shortest sleep duration studied.
So inadequate sleep is not simply an individual problem. It is a widespread public-health issue.
7. Circadian rhythm and meal timing matter
I found this part particularly interesting because it connects directly with the previous section on caloric restriction and early dinner.
Our circadian clock influences virtually every organ system, including the gut, liver, muscles, immune system, and heart.
The gut microbiome also follows daily rhythms. Irregular meal timing can disrupt these internal clocks and contribute to impaired glucose regulation.
This is why Topol recommends maintaining a consistent daily pattern of eating and leaving several hours between dinner and bedtime.
In other words, when we eat may matter almost as much as what we eat.
8. For insomnia, CBT-I comes first
Topol emphasizes that the first-line treatment for chronic insomnia should be cognitive behavioral therapy for insomnia (CBT-I) rather than immediately turning to medication.
Digital, app-based CBT-I has also shown benefits in large trials.
By contrast, evidence for supplements such as melatonin, magnesium, and ashwagandha is relatively weak, with generally modest effects. Topol is also skeptical of expensive high-tech sleep products when strong evidence of benefit is lacking.
And there is an interesting warning about sleep trackers: they aren't necessarily precise, and becoming obsessed with sleep scores can actually create anxiety and make sleep worse.
9. Simple sleep habits still matter
Topol's practical advice:
Keep a consistent sleep schedule.
Exercise regularly.
Eat on a consistent schedule and finish dinner several hours before bedtime.
Keep the bedroom cool, dark, and quiet.
Limit exposure to blue light from electronic devices before bed.
Sometimes the most effective interventions are also the least complicated.
10. Don't overlook sleep apnea
Sleep apnea is common, particularly among older adults, and many people with it may not experience obvious daytime sleepiness.
Warning signs include loud snoring, gasping or choking during sleep, pauses in breathing, and disrupted sleep.
Topol emphasizes that untreated symptomatic sleep apnea is associated with at least a twofold higher risk of cardiovascular and metabolic disease.
The big picture
Topol's message is that sleep is an active biological process essential to maintaining the brain, heart, metabolism, immune system, and overall health.
For healthy aging, his practical formula is:
Sleep about seven hours, keep a regular schedule, eat earlier, exercise regularly, protect your sleep environment, and take possible sleep apnea seriously.
