You may wake up and immediately reach for your beans, but there is a better window to drink coffee in.
Studies show stress hormone cortisol reaches high levels when we wake up, so having a coffee early boosts it more and leave us feeling iffy.
So, experts reckon the best time to boil the kettle is between 9.30am and 11am.
Amanda Maucere, a sports nutritionist in Florida, previously told health website Well and Good: "Although there hasn't been much research done in humans on the interplay between coffee, cortisol, and the circadian rhythm, we know enough about each one separately to suggest that waiting a little bit before having that first cup of coffee in the morning is a good idea."
She added: "Although helpful for 'waking up', elevated levels of cortisol are also found in times of stress to be harmful.
"So, if you combine an already elevated cortisol with an additional spike from coffee, you create an unnecessary stress response in the body.
"This response would be mitigated by waiting an hour or so before enjoying your morning cup of joe."
Meanwhile, drinking coffee half an hour before exercising is the best time to get good results from adrenaline, according to a review of dozens of studies by the US-based International Society of Sports Nutrition.
As for trying to get to sleep, caffeine blocks receptors for the hormone adenosine and melatonin which can make napping harder.
So people should avoid it from six hours before bed, according to the US Food and Drug Administration (FDA).
However, Dr Dierdre Conroy, a sleep expert at Michigan University, recommends stopping drinking coffee eight hours before bed.
She told the Mail: "People have very different sensitivities to caffeine and people who consume caffeine more often might respond differently to those who don't drink it at all.
"But in general, our guideline is eight hours before going to bed, you should eliminate all caffeinated products."
So now you know everything you need to know to make that flat white really bang.
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