Why I Care More About When You Wake Up Than When You Go to Bed

Sleep is an amazing process. We literally grow during sleep. Growth hormone secretion peaks, promoting muscle repair and bone growth. Most of our prolactin hormone, which plays a crucial role in reproductive health and immune system regulation, is produced during sleep. During sleep, the brain cleanses itself through the glymphatic system which flushes out metabolic waste products, toxins, and proteins like amyloid. Since I’m keen on preventing dementia, I am interested in learning how I can optimize sleep. Here’s what I’ve learned.

Sleep is not something you do. Sleep happens to you.

Sleep is like breathing. It just happens. What we can do is create conditions that make it easy for sleep to happen:

• Get morning sunlight (and throughout the day if possible)

• Avoid caffeine after 12

• Stop eating 3 hours before bed

• Make the room dark and cool (65 degrees)

• I put away screens 15 minutes before bed (I wish I could do more)

• I read a paper book or do some box breathing right before bed

Then let sleep happen.

Consistent Wake Up Time Matters

Most patients think better sleep starts at bedtime.

It starts when you wake up.

People ask about magnesium, melatonin, blue-light glasses, blackout curtains, temperature control, trackers, and supplements. All of those can matter but they’re downstream.

If I had to pick one variable that most strongly predicts whether someone’s sleep, metabolism, and circadian rhythm improve, it wouldn’t be bedtime.

It would be wake time consistency.

Our internal clock doesn’t run on a perfect 24-hour cycle. We evolved with a circadian rhythm that averages about 24.2 hours. To stay synchronized with the Earth’s 24-hour light–dark cycle, our brain needs daily recalibration. That recalibration happens in the brain (suprachiasmatic nucleus) and it depends primarily on morning light exposure after waking. This is why wake time matters more than bedtime.

In long-term studies of shift workers and non-shift workers alike, people with consistent wake times show:

• better metabolic markers

• improved insulin sensitivity

• more stable lipid profiles

You can sleep eight hours and still be circadian-misaligned.

Sleep regularity is a stronger predictor of mortality risk than sleep duration (reference). This is why I care more about when you wake up than when you go to bed.

A prospective cohort study from the UK Biobank examined sleep using objective accelerometer data from ~60,000 participants (mean age 62.8 years, 55% female) followed for up to ~8 years.

Sleep regularity was independently associated with reduced mortality risk. Participants with high sleep regularity had 20-48% lower all-cause mortality, 16-39% lower cancer mortality, and 22-57% lower cardiometabolic mortality compared to the least regular sleepers.

Sleep regularity outperformed sleep duration as a mortality predictor. Two individuals sleeping the same number of hours did not carry the same risk if one had highly irregular sleep timing. Circadian disruption affects autonomic tone, glucose regulation, inflammation, and cardiovascular physiology. Duration captures quantity. Regularity captures circadian rhythm.

As Michael Grandner, Director of the Sleep and Heath Research Program at the University of Arizona and Director of the Behavioral Sleep Medicine Clinic emphasized in his conversation with Rhonda Patrick (reference), sleep is not just about quantity. Timing regularity plays a central role in cardiometabolic risk, inflammation, and long-term health.

Duration: Seven Might be The New Eight

The American Academy of Sleep Medicine and Sleep Research Society reviewed extensive evidence on sleep duration and mortality, finding that self-reported sleep duration of 7-8 hours was generally associated with the lowest mortality risk (reference). I highlighted the term “self-reported” as I wonder if people tend to overestimate their sleep duration. If I go to bed at 10pm and wake up at 6am (8 hours), it is hard to know how much time I actually slept. I might estimate 7-7.5 hours (assuming it took some time for me to fall asleep and I woke up once to use the bathroom).

However, in that scenario my Oura ring usually says I slept 6.5 hours because it notes other times I was awake but I don’t remember. So 6.5-7 hours on a sleep tracker might be equivalent to 7-8 hours of self-reported sleep.

Side note: I know that sleep trackers are not perfectly accurate, but they are most accurate when it comes to sleep duration (esp in healthy sleepers).

Chronic Insomnia Has One Cause: Conditioned Hyperarousal

Once you rule out sleep apnea (more common than you think) and acute insomnia, most persistent sleep problems come from conditioned hyperarousal. This is a fancy way of saying that our brain begins to associate sleep as a stressful process. The thought runs through our head, “Oh no, how am I going to fall asleep?” Suddenly we find ourselves trying to fall asleep and being unable to do so.

What’s the most evidence-based way to address chronic insomnia? It’s not melatonin, magnesium, Ashwagandha, or even prescription sleep medications. It’s cognitive behavioral therapy for insomnia (CBT-I).

CBT-I is a structured program that targets the thoughts and behaviors that maintain sleep problems. Unlike sedative medications, which treat the symptoms of insomnia, CBT-I aims to address the underlying causes. It is typically delivered over 4 to 8 sessions and involves a combination of several different strategies:

1. Stimulus Control Therapy

The goal is to strengthen the mental association between the bed and sleep.

• Use the bed only for sleep and sex.

• Go to bed only when sleepy.

• If you can’t sleep after 20 minutes, leave the bedroom and do something relaxing in dim light until you are sleepy again.

2. Sleep Restriction (Compression)

This technique limits the time spent in bed to the actual amount of sleep you are currently getting. By creating a state of mild sleep deprivation, it increases “sleep drive,” leading to a more consolidated and deeper night of rest. As sleep efficiency improves, the time allowed in bed is gradually increased.

3. Cognitive Therapy

This involves identifying and challenging dysfunctional beliefs about sleep. Common targets include:

• Catastrophizing: “If I don’t sleep tonight, I’ll fail my presentation tomorrow.”

• Unrealistic Expectations: “I must get 8 hours of sleep every single night to function.”

• Anxiety over Sleep Loss: Reducing the “effort” often put into trying to force sleep.

4. Relaxation Training

Techniques such as progressive muscle relaxation, mindfulness, or breathing exercises are used to reduce autonomic arousal.

The goal is CBT-I is to help your brain stop seeing the bed as a place of frustration. Here is a link to a great CBT-I workbook you can do on your own.

Bottom line

Stop trying to sleep. Start deciding when to wake up.

The evidence is clear: regularity beats duration and cognitive behavioral therapy beats pharmacology. If you want to optimize your metabolic health and protect your brain, stress less about the “8-hour” myth and aim for consistent wake up times.

Pick a wake-up time, stick to it for seven days—even on the weekend—and watch how your relationship with the night begins to change.