Experts have warned against having a coffee first thing in the morning as it can hijack our body's natural rhythm, prompting us to have that afternoon crash.

A spokesperson from Oddy Knocky Coffee told Express UK, "The body makes something called adenosine - which makes you drowsy - and cortisol, the so-called' stress hormone'. Both of these chemicals impact how well our daily dose of caffeine hits.

"Adenosine starts off low in the morning after we first wake up and increases more and more throughout the day, so by bedtime, you're naturally tired. Cortisol, on the other hand, is at its highest levels in the morning.

"Drinking coffee right after waking up is probably not the best way to keep your body's internal clock on track as it fights with these other chemicals in your brain that are all trying to do different things for you.

"This conflict of chemicals messes you up in the morning, keeping you unfocused and unproductive. This is the opposite of what our beautiful coffee is supposed to do for us."

So when should we reach for that cup of joe?

Sleep expert from Get Laid Beds, Dr Deborah Lee, explained that the best time for a morning coffee is at 10 am or at least 45 minutes after you get up in the morning.

This is due to the cortisol, the stress hormone, peaking within 30-45 minutes of waking up and declines as you progress through your day. Dr Lee said that drinking it earlier than that can make you "immune" to coffee over time.

"If you're someone that wakes up at around 7 am, for example, leaving your first coffee until around 10 am to 12 pm will be when your body and mind will appreciate it the most, and you'll get the most benefits from the caffeine," she told the Daily Mail.

"Taking into account your own rhythm, the best time to have your caffeine fix would be, at the earliest, 45 minutes after waking up - when your cortisol rhythm starts to dip."

Dr Lee went on to explain that the stress hormone is at its peak about 45 minutes after you wake up in order to enhance alertness and focus.

"Elevated levels of cortisol may impact your immune system, and if they're already at its peak when waking up, drinking coffee as soon as your eyes open may do more harm than good, and may even make you immune to caffeine over a long period of time."

It is also recommended to stop drinking coffee six to eight hours before your bedtime as it can prevent you from having a good night's rest.

"To avoid messing up your sleeping pattern, avoid any caffeine after 3 pm, including coffee, fizzy drinks, energy drinks and even non-caffeinated tea.

"Try switching to herbal teas if you need a hot drink to stay warm, or decaf to trick yourself into thinking you're getting your caffeine fix. Your sleep schedule will thank you!"