"One of the most important things you should do first thing after waking up is to get outside and expose your skin to natural sunlight" for around 30 to 45 minutes, Dr Deborah Lee from Dr Fox Online Pharmacy told the Daily Express exclusively. Doing so could "set you up for a lifetime of good health benefits", according to the expert. Exposure to sunlight should happen "within an hour of getting out of bed". "The sun is at its weakest in the early part of the day than later on," explained Dr Lee, who advised wearing sunscreen but not sunglasses. "You want the light to get to the back of your eyes." Read More: Five foods to eat to debloat, according to a gastroenterologist This can help to keep your body clock in check, regulating your sleep and even reducing your risk of Alzheimer's. "The body's metabolic and physiological processes are driven by its circadian rhythms, the body's natural timekeeper," she explained. This is "a specialised group of cells called the suprachiasmatic nucleus [SCN], which is situated in the hypothalamus, behind your eyes at the base of your brain". In order to work effectively, "the SCN needs to be able to tell the difference between day and night very clearly. The SCN is the body's master central pacemaker - but, fascinatingly, it also communicates with the cellular clocks of every other cell and tissue in the body." "When we are asleep our brains and bodies are far from inactive - a whole host of metabolic processes are getting to work," she added. Read More: Not getting enough sleep could be having a bigger impact on you than you think