There are evenings when you feel almost exhausted, but still cannot fall asleep: as if someone inside has switched your “day” and “night” modes. In the morning it is hard to get going, after lunch you are overwhelmed by sleepiness, and closer to midnight a strange surge of energy appears. Behind these swings there is often not “weak willpower”, but the sleep hormones — cortisol and melatonin — and how they align with your daily rhythm.
In the big guide about sleep and the nervous system we have already looked at how stress affects the brain and falling asleep. In this article we will see what happens on the hormonal level: how cortisol and melatonin work, why their schedule can “slip”, and what you can do to gently support your rhythm.
What is the circadian rhythm and why is it important for sleep?
Inside the brain there is a small structure — the suprachiasmatic nucleus, often called the “internal clock”. It receives signals from light, movement, eating patterns and helps the body synchronise with the “day–night” cycle.
The circadian rhythm affects:
- the time when you naturally want to fall asleep;
- the depth and continuity of sleep;
- your energy level and concentration at different hours of the day;
- appetite, mood and the ability to cope with stress.
Cortisol and melatonin are two key hormones that help this internal clock work in a coordinated way. When their rhythms shift, sleep rarely remains the same.
How do cortisol and melatonin work throughout the day?
Cortisol is often called the “stress hormone”, but its basic role is not to “ruin your life”, but to help you wake up, focus and respond to the challenges of the day. In a healthy rhythm its level:
- rises in the morning — so that you feel alert and can get out of bed;
- gradually decreases during the day;
- stays low in the evening, giving the body the signal “it is time to slow down”.
Melatonin is the hormone that the brain produces in response to darkness. Its level:
- is low during the day when there is a lot of light;
- starts to rise in the evening, about 1–2 hours before your natural sleep time;
- reaches its peak at night, supporting sleepiness and deep sleep;
- drops by morning, helping the body wake up.
In simplified form it looks like this: in the morning cortisol dominates, in the evening — melatonin. When these curves overlap correctly, falling asleep and waking up become more predictable and less dramatic.
How do stress and evening habits disrupt the hormonal rhythm?
If during the day you live in a state of chronic tension, cortisol can remain elevated longer than necessary. And if the evening passes in front of a bright screen and news, melatonin receives fewer signals that “it is time to switch on”.
The hormonal rhythm is influenced by:
- Chronic stress. When the body constantly expects danger, cortisol can also rise in the evening. In this state it is hard to “switch into” sleep even if you are exhausted.
- Screens before bed. Bright blue light from phones, laptops and TVs slows down melatonin production. We write about this in more detail in the article about screens, blue light and sleep.
- Irregular daily routine. Late wake-ups at weekends, constantly shifting bedtimes and mealtimes confuse the signals for the internal clock.
- Caffeine and alcohol. Coffee in the second half of the day can keep the nervous system in tone even when melatonin is already trying to “pull the curtain”. Alcohol sometimes helps you fall asleep faster but makes sleep more shallow and fragmented.
This is not about you “doing everything wrong”, but about understanding that hormones have their own pace, and some habits can speed it up or shift it in a way that makes it harder to fall asleep.
What signs may indicate that cortisol “does not have time to calm down”?
Without tests you cannot say for sure that your cortisol is elevated, but there are typical signals that are worth treating as a reason to look more closely at your rhythm:
- an evening feeling of a “second wind”, when after fatigue there is suddenly a surge of energy and it is hard to stop;
- a feeling that the body seems tense even in bed: it is hard to relax your shoulders, jaw, stomach;
- frequent night-time awakenings with thoughts about work, money, safety;
- morning exhaustion, as if you “worked” all night, although you formally slept;
- a constant desire to control everything down to the smallest detail, which does not let go even before sleep.
These signs do not automatically mean a hormonal disorder. But they show that the nervous system lives in a state of high anxiety, and cortisol may not have time to drop by the evening. In such a situation gentle evening rituals are especially helpful (we talk about them separately in the article about evening habits for better sleep) and grounding practices with prolonged exhalation from our article about body-based tools for sleep.
What happens when there is too little melatonin or it is “late”?
A low or delayed melatonin peak often shows up as:
- prolonged falling asleep: you go to bed but stay “switched on” in thoughts and planning for a long time;
- a shifted rhythm: you fall asleep closer to two or three in the morning, and it is hard to get up even with an alarm clock;
- a feeling that real clarity and productivity arrives closer to the evening, when others already want to end the day;
- increased sensitivity to light: even a small bright lamp or screen can “chase away” sleepiness.
Sometimes people try to solve this on their own by buying melatonin supplements. But without consulting a doctor this may give only a temporary effect or not hit the right timing at all. It is important first to look at the basics: light during the day, bedtime routine, screens, evening habits.
How are stress, hormones and anxiety connected with daytime “switching off”?
When the circadian rhythm is disrupted, the body can “slip” into sleep where you did not plan it at all. There are episodes of sudden daytime sleepiness, difficulties with concentration, a feeling that the brain “shuts down” in the middle of the working day.
We write in detail about these states — daytime sleepiness and microsleep — in the article about the constant desire to sleep during the day. The hormonal rhythm plays an important role here: if cortisol was high at night and melatonin did not have time to do its work, during the day the body literally tries to “catch up” on rest.
How to gently support cortisol and melatonin without fanaticism?
Hormones are not something you can “flip like a switch”. But there are steps that help the internal clock feel day and night again.
It is helpful to pay attention to several directions:
- Morning light. Go out into daylight within the first hours after waking up. This helps the internal clock synchronise and gives cortisol a “legitimate” signal to be active in the morning.
- A warm, predictable evening frame. Small rituals — a warm shower, tea, a book instead of the news — give the nervous system the signal “we are slowing down”. We collected examples of such habits in the article about evening rituals.
- Gentle reduction of screens. Even if it is impossible to give up gadgets, you can at least remove the most emotional content an hour before sleep and reduce brightness.
- Regular sleep and wake times. If you go to bed and get up at roughly the same time every day, it is easier for the internal clock to tune hormonal waves.
- Working with anxiety. When thoughts especially accelerate in the evening, a simple sleep and anxiety diary helps: it takes part of the load off night-time ruminations.
These steps do not replace medical examination, but they create conditions in which the hormonal rhythm has a chance to return to a more natural pace.
When should you see a doctor about sleep and hormones?
There are situations when changes in habits are no longer enough and it is important to involve a specialist — a family doctor, neurologist or endocrinologist. Reasons for consultation may include:
- long-lasting (weeks and months) sleep disturbances, when you almost every evening cannot fall asleep or often wake up;
- pronounced daytime sleepiness that makes it difficult to work, study or care for children;
- sudden night-time awakenings with strong heart palpitations, shortness of breath, inner trembling;
- noticeable fluctuations in weight, appetite, mood without obvious reasons;
- a feeling that you have almost no strength even after seemingly normal sleep.
A doctor may recommend tests, examinations, adjustment of treatment for other conditions or refer you to a psychotherapist. Your task is not to “prove” that the problem is serious enough, but to bring an honest picture of how you sleep and how you feel.
How to look at sleep hormones without self-blame?
It is easy to start thinking “I have ruined my cortisol and melatonin myself” — especially if there has been a lot of stress, hard years, night work or childcare. But hormones are not a verdict and not an assessment of how “correct” you are. They are a living response of the body to the conditions you found yourself in.
It may be helpful to ask yourself a few questions: “What small changes in my daily rhythm can I make right now?”, “What helps my body feel day and night more clearly?”, “Which specialist could support me at this stage?”. In this way the focus shifts from guilt to care and real steps.
Cortisol and melatonin do not exist in a vacuum: they respond to your days, stresses, joys, information background and those small gestures of support you give yourself every day. The more attentively you relate to your rhythm, the greater the chance that your nights will become calmer and your morning less like a struggle with yourself.
