Tiredness and coffee: how they link to poor sleep and how to break the loop

How does the loop between tiredness and coffee work?

It goes roughly like this:

1. You sleep badly or too little.
2. The next day you're tired and drink more coffee, including in the afternoon.
3. The caffeine stays in your body until evening and makes your sleep shorter and lighter.
4. The next day you're even more tired and drink even more coffee.

Each step seems logical. Together, they make a loop that keeps tightening. And often you don't notice, because you fall asleep easily enough; it's just that the sleep is poorer.

What does caffeine do in the body?

Through the day, a substance called adenosine builds up in the brain and makes you feel the need to sleep. Caffeine blocks the places where adenosine should act. That's why you feel more alert, even though the tiredness is still there, only covered up.

Caffeine stays in the body for many hours. A study published in 2013 gave people a large dose of caffeine (400 mg) at bedtime, 3 hours before or 6 hours before. In all three cases, sleep was worse than without caffeine. The authors advised against large amounts of coffee in the 6 hours before bed.

How much coffee is fine?

The European Food Safety Authority (EFSA) considers that, for healthy adults, up to 400 mg of caffeine a day and up to 200 mg at a time raise no concerns. For women who are pregnant or breastfeeding, the limit is 200 mg a day.

Drink	Caffeine, roughly
A mug of filter coffee (200 ml)	90 mg
An espresso	80 mg
A cup of black tea	50 mg
A can of energy drink (250 ml)	80 mg
A can of cola (330 ml)	40 mg

Values vary a lot with the coffee and how it's made, so the table is only a guide. For most people, 3–4 cups a day are fine, as long as they're drunk in the morning and at lunchtime.

Which link do you break first?

You don't have to give up coffee. Moving the last cup is enough:

• Last coffee before 1–2 pm, if you go to bed around 11 pm.
• In the afternoon, decaf or a herbal tea, if you like the ritual.
• When the after-lunch dip hits, try 10 minutes of walking or a glass of water first.
• In the morning, have your coffee after breakfast rather than the moment you wake up, if you like; some people then feel less need for another.

After a week or two, many people notice they fall asleep more easily, wake up more rested and need less coffee the next day. The loop comes apart on its own.

How do you cut down on coffee without headaches?

If you've drunk a lot of coffee for a long time, stopping suddenly can bring a few days of headaches, tiredness and irritability. It isn't dangerous, but it's unpleasant, and many people go back to coffee just to get rid of it. It's easier step by step:

1. Week 1: move your last coffee before 2 pm, without changing how many you have.
2. Week 2: swap one of your coffees for a decaf or a tea.
3. Week 3: drop one more, if you feel you need less.

Drink water during these days. Sometimes part of the afternoon tiredness is actually thirst. And don't judge yourself if you have an extra coffee on a hard day. What counts is what you do on most days.

What do you learn from this loop?

That health problems rarely come alone. Tiredness, coffee, sleep, sugar cravings and lack of movement are all linked. That's why one small step, in the right place, can change more than ten rules brought in at once. Learning how things connect for you is the most useful part.

How does MentorSano help you break the loop?

• The daily journal keeps your coffee, sleep and energy, day by day, in a minute or two.
• The daily lesson explains in a few minutes why you feel what you feel, linked to what you're working on.
• Progress on a chart: sleep and energy have scores calculated from your journal, so you see for yourself whether moving your coffee changed anything.
• With the subscription, the plan checked by an expert finds the link to break for you: a small step you can keep, linked to all your other data.

The journal and the lessons are free. Create your free MentorSano account and for two weeks note the time of your last coffee next to how you slept.