
Why coffee does NOT give you extra energy: Scientist says pick-me-up is just a ‘loan’ that needs to be paid back with sleep
- Caffeine temporarily blocks a chemical called adenosine preventing drowsiness
- But eventually, adenosine binds to its receptor, making us sleepy and drowsy
- Dr Emma Beckett is a molecular nutritionist at Newcastle University
When it comes to waking up in the morning, most of us rely on a cup of coffee to give us the boost we need.
But your flat white, Americano or latte won’t actually give you extra energy – but rather borrow it, according to an expert.
Newcastle University molecular nutritionist Dr Emma Beckett said that this ‘readiness’ to feel awake will eventually have to be repaid with sleep.
She explained that caffeine prevents drowsiness by temporarily blocking a chemical called adenosine.
This chemical is part of the system that regulates our sleep and wake cycle, with levels increasing throughout the day as it is released as a byproduct when energy is used by our cells.

Caffeine staves off drowsiness by temporarily blocking a chemical called adenosine, Newcastle University molecular nutritionist Dr Emma Beckett wrote on The Conversation website.
Eventually, adenosine binds to its receptor – part of cells that receive signals – which instructs cells to slow down, making us sleepy and sleepy.
Caffeine can help us feel awake by binding to the adenosine receptor and blocking the chemical from triggering the feeling of sleepiness.
“But there is a catch,” Dr. Beckett wrote on The Conversation website. “While energizing, this little caffeine intervention is more of a borrowing from the feeling of arousal, rather than creating new energy.
“That’s because caffeine doesn’t bind forever and the adenosine it blocks doesn’t go away.
“So eventually the caffeine breaks down, lets go of the receptors, and all that adenosine that’s been waiting and building up locks in, and the feeling of drowsiness comes back — sometimes all at once.”
“So the debt you owe to caffeine still has to be paid off, and the only real way to pay it off is to sleep.”
Dr. Beckett explained that while we sleep, adenosine levels drop because we use less energy, which means we wake up in the morning feeling refreshed.
Drinking coffee later in the day, when there’s more adenosine in the body, may seem more potent than a morning cup, she said.
And if you like your coffee with sugar, it could add to the possible feeling of “crash” following a spike in blood sugar, she added.
“Caffeine can help, but it’s not magic,” Dr. Beckett said. “To create energy and re-energize our bodies, we need enough food, water and sleep.”
Caffeine found in tea, energy drinks and other beverages is said to have a similar impact on the body, she wrote.
A recent study found that drinking two to three cups of coffee a day may be linked to a longer lifespan.
The researchers found that two to three cups a day were associated with up to 27% less chance of death than those who drank none at all.
The findings, published in the European Journal of Preventive Cardiology, apply to ground, instant and decaffeinated varieties, with the researchers saying coffee drinking should be considered part of a healthy lifestyle.
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