According to the experts, adults need between seven and nine hours of sleep a night. You know that feeling tired can make you grumpy, but did you know that it also affects your response times and inhibits the rational decision-making part of your brain?
If you need to wake up fast, these tricks will help you get through until you can have a nap or an early night. Just remember never to drive or operate machinery when sleepy.
See also: Six insomnia myths you need to know
1. Let there be light
Light acts as a natural 'wake up' call to the brain - whether that's first thing in the morning or late at night. Night workers who were exposed to bright light at the end of their shift were more alert than those who were not, according to a study published in the American Academy of Sleep Medicine.
Open the curtains wide, go for a walk in the sunshine, or consider sitting next to a blue spectrum lightbulb for 20 minutes.
2. Get your blood pumping
When you're tired, the last thing you want to do is exercise. But getting moving is one of the best ways to wake up, as it will direct blood flow to the brain.
You don't have to jog around the park, walking up and down the stairs is enough according to researchers from the University of Georgia. They found that after 10 minutes of climbing the stairs, sleep-deprived people felt more energised than when they took caffeine energy pills.
Alternatively, try leaning over to touch your toes. It will send a rush of blood to your brain, making you feel instantly more awake.
3. Splash your face with cold water
Sometimes the old remedies are the best. If you need a pick-me-up, splash your face with cold water. Cold water acts as a stressor, causing the body to release hormones like adrenaline, which makes you instantly alert. If you can stand it, try having a cool (not cold) shower once you wake. Not only does the cool water encourage blood flow, it also causes the body to release endorphins that stimulate the brain.
4. Do some deep breathing
The more oxygen you can get to your brain the better, and breathing slowly and deeply can make you more alert and feel more focused.
Try doing deep breathing and then shake out your limbs to help shrug off the tired feeling. Forcing yourself to stay awake when you want to sleep puts stress on the body, and breathing deeply can help combat the headache that often comes with tiredness.
5. Sip some lemon and water
Even mild dehydration can zap your energy levels and leave you feeling more tired. While a cup of coffee will improve your alertness in the short-term, it can leave you feeling jittery if you're very tired. Instead, opt for some hot or cold water with a few slices of lemon, orange or lime. Citrus smells are known to be energising.
6. Sniff some peppermint
There's nothing like the sharp, clean smell of peppermint to make you feel bright and awake. Studies show that sniffing peppermint oil can improve short term memory, and increase the brain's production of alpha waves, electrical impulses that can produce a happier mood.
7. Wear something bright
If you're too tired to face the day, put on your brightest shirt or dress. Colour can have a surprising influence on our mood and energy levels. Red, orange and yellow are all energising.
8. Chew some gum
Finally, try chewing some gum. Research has shown that chewing can increase alertness and improve mood - and the strong peppermint smell will help to pep you up too.