What’s actually going on
How I think about this.
Sleep is the easiest thing to wreck and the hardest thing to actually fix. Sleep breaks in two ways: trouble falling asleep and trouble staying asleep. They almost always come from different causes.
Sleep-onset trouble can be a stress-hormone pattern. Cortisol that should fall through the evening stays elevated, often driven by late-evening eating, alcohol, screen light, or chronic stress that has trained the system to be vigilant after dark.
Stay-asleep trouble, the 3am wake, is worth reading for a blood-sugar pattern first and an adrenal-rhythm pattern second. Glucose drops in the second half of the night, the adrenal system fires cortisol to pull it back up, and you wake. Alcohol in the evening makes both of these worse. So do magnesium and B-vitamin gaps. So does light exposure after sunset.
Before anything else
When poor sleep needs medical evaluation.
Everything further down this page is about physiology that can contribute to this symptom. None of it replaces a conventional diagnosis, and some presentations need to be seen rather than measured. Start here.
Get emergency care now
- Falling asleep involuntarily while driving or operating machinery
- Thoughts of harming yourself. In the US, call or text 988
If any of these apply, this page is not the right next step. Call 911 or go to an emergency department.
See a physician promptly, within days
- Witnessed pauses in breathing, choking or gasping during sleep, or loud habitual snoring
- Sudden loss of muscle tone with strong emotion, or sleep attacks during the day
- Acting out dreams physically during sleep
- New insomnia alongside significant weight loss, night sweats or breathlessness lying flat
Worth a routine medical evaluation
- Insomnia most nights for more than three months
- Daytime sleepiness that interferes with work or driving
- Sleep problems that began with a new medication
- Restless, crawling sensations in the legs at night that improve with movement
If sleep apnoea has been considered or excluded and the pattern tracks with light, timing, stress or meals, the systems above are a reasonable place to look.
This list covers the presentations that most often need conventional assessment. It is not exhaustive, and it does not replace clinical judgement. If something feels wrong and is not on it, that is still a reason to be seen.
Systems that can contribute
Where poor sleep can come from.
Each of these can be part of the picture. None of them is the answer on its own, and finding something here does not establish that it is the reason you feel the way you do.
Circadian timing
Light exposure, meal timing and schedule consistency set the phase your sleep system is working to. Sleeping at the wrong phase produces poor sleep at normal duration.
Stress-hormone rhythm
Cortisol is meant to fall through the evening. When it does not, sleep onset can be difficult even when you are tired.
Glucose regulation
Overnight glucose dips can be associated with waking in the second half of the night.
Airway and breathing
Obstructive sleep apnoea is common, frequently undiagnosed, and a major cause of unrefreshing sleep. It is not something a blood panel detects.
Sex hormones
Falling progesterone and vasomotor symptoms during the menopausal transition are a well-recognised contributor to disrupted sleep.
Substance and medication effects
Alcohol, caffeine timing, nicotine and several prescription classes affect sleep architecture even when they do not affect sleep duration.
The physician’s lens
How I read this in practice.
I read poor sleep against the daily cortisol curve and the glucose response to evening food. A salivary cortisol panel across the day. Blood sugar tracked with a CGM if the case warrants it. The metabolomic read for the magnesium and B-vitamin story. If sex hormones are in the mix, perimenopause, low testosterone, those go on the same draw as everything else.
The systems behind it
Where this symptom comes from.
Most cases touch more than one. Open each area to read the biology underneath.
Biological pillars
Pillar
Chronobiology.
Every hormone, immune function, and metabolic process runs on a circadian schedule. The disruption is measurable, and the consequences are systemic.
Read this pillarPillar
Mitochondria & Cellular Energy.
Mitochondria produce most of the energy every other function depends on. Aspects of that function can be assessed, and much of it responds to how you live.
Read this pillarPillar
Exposomics.
The cumulative environmental load a person carries can matter for physiology. Some of it can be measured, and I assess it when your history says it is relevant.
Read this pillar
What measurement settles
What testing can and cannot tell you here.
Testing can help identify
- Identify thyroid dysfunction, iron deficiency relevant to restless legs, and glucose patterns overnight
- Show hormonal changes relevant to sleep during the menopausal transition
Testing cannot by itself establish
- Diagnose sleep apnoea, which requires a sleep study
- Measure sleep architecture, which no blood panel reports
- Establish why you are sleeping badly, since sleep is behaviourally and environmentally driven as much as biochemically
What may help clarify it
The data that explains it.
Sleep is best read with the daily cortisol curve, blood sugar in real time, and a check on the nutrients that calm the system at night. Sex hormones come into the read when life stage warrants it.
What I would measure
The hormone network, measured together
Reads the cortisol axis, thyroid, and sex hormones in a single draw. The hormonal foundation for sleep.
Explore working with Dr. TaggeWhat I would measure
Cardiometabolic markers
Two weeks of glucose data answers the 3am wake question with more clarity than any single lab can.
Explore working with Dr. Tagge
While you wait
Moves worth making before testing.
These are the levers I’d pull while we set up the workup. Most of them produce real signal inside two weeks.
- Bright light within an hour of waking. Outside if at all possible. This is the most powerful sleep signal you can give yourself.
- Stop eating three hours before bed. Especially carbohydrates.
- Anchor your wake time. Let bedtime drift toward it for two weeks before changing anything else.
- Cut alcohol entirely for two weeks. The second half of your night will look different.
If two weeks of the basics doesn’t move the needle, that is the kind of presentation a call with me exists for. Your biology is telling you something the lifestyle layer cannot fix on its own.
The right order
Get this evaluated first.
This symptom warrants standard medical evaluation before optimization-focused testing. Your own physician is the right place to start. Once that is underway, the Precision Health Assessment can add the layer conventional workups usually leave out.
What to read next
Go one level deeper.
- How I think
- The framework: how a symptom, a result and a history are read together, and why a reference range is not the same as a person’s range.
- The systems
- Chronobiology · Mitochondria & Cellular Energy · Exposomics
Essays on this
Essay
EMF exposure and health: the honest answer.
The EMF discourse oscillates between dismissal and catastrophe. The honest position is that the evidence for harm at typical exposure levels is weak, the harm-mitigating habits are cheap, and one specific exposure (phone in the bedroom) is worth addressing for reasons beyond EMF.
Read thisEssay
The evolutionary basis for different chronotypes.
Some people are wired to wake early. Some are wired to stay up late. The variation almost certainly served a survival function in human history, and understanding your own chronotype is one of the higher-leverage lifestyle interventions available.
Read thisEssay
The evolution of sleep. Why humans slept in tribes.
For most of human history, people slept in groups, with variable timing, and without the modern apparatus of bedrooms and total darkness. Understanding why helps explain some of the modern sleep paradoxes.
Read this
Browse other symptoms
Something else on your mind?
Fatigue and low energy
When the tank stays low no matter how much you sleep.
Brain fog
The lights are on but the signal feels weak.
Poor sleep
Either you can’t fall asleep, or you can’t stay asleep.
Perimenopause
The years when the body’s hormonal rhythm changes, before the period stops.
Low libido
Desire that used to be reliable is gone or muted. Both sexes, both directions.
Hair loss
Thinning, shedding, or texture changes that didn’t used to happen.
Erectile dysfunction
ED is the canary. The body is telling you something about vascular and hormonal health.
High cholesterol concern
Your last lab flagged it. You want a second opinion before you take a statin.
High blood pressure concern
The reading came back elevated. You want the full picture before you start a prescription.
Food cravings
Cravings are biology pulling for what it needs, disguised as whatever is easiest to grab.
Creating Health with Dr. Daniel Tagge
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You start with a free call: a brief conversation about what you are looking for and whether we are a good fit. After the call I recommend the step that fits: the Precision Health Assessment, or ongoing care as my patient.