Spending just a few hours too little in your double bed can completely throw your body clock out of kilter, but it takes days or even weeks to get it back on track, according to Canadian Business (CB). That’s why you need to take your sleep seriously. CB recommends that you don’t consume caffeine after three pm and that you sip cold water when you are feeling sleepy. They warn against alcohol, which can disrupt your night's sleep. If you haven’t managed to get your required amount of sleep at night, you may want some daytime shut eye. Sleep researcher and assistant professor Henry Olders from McGill University advises you keep them short. "Naps are definitely a good way to help you feel more rested, but keep them to about ten to 15 minutes, ideally," he said, "any longer than half an hour and you risk sleep inertia, which will hurt your focus.” Mr Olders explains that the best thing you can do is to get into a pattern that sees you sleep for the same length of time every day of the week, even weekends. This is a good way to feel rested. To feel more awake at work, try to sit where you can see the sun. Natural sunlight tells your body to stay awake, so you should feel more on-the-ball.