Pakistan, Feb. 16 -- Most people will head to the coffee machine as soon as they wake up, but doing that isn't going to give you the biggest energy-boost, according to sleep expert.

Caffeine works by blocking sleep-promoting receptors in your brain called adenosine receptors, explaining why people who drink caffeine too late in the day may struggle to sleep at night.

Doctor Deborah Lee, Sleep Expert working with Get Laid Beds, wooden bed makers in the US and UK, discusses when the best time to drink coffee is, as well as why you shouldn't drink coffee as soon as you wake up.

Why doesn't coffee work as soon as you wake up?

"When you wake up, your stress hormone cortisol level is at its peak, which is a hormone that enhances alertness a...