Lisa Artis, deputy CEO of The Sleep Charity, tells Stylist: “There are a number of reasons why we are more tired and need more sleep as we head into the colder months. These include having less exposure to sunlight during the day.”

Sleep expert James Wilson, aka The Sleep Geek, adds: “When the mornings are darker, we are not being signalled into wakefulness. So it is harder for us to get light during the day (particularly in the morning which is beneficial for our body clock) then we often feel more lethargic.”

As Artis explains: “Low light decreases serotonin, which regulates mood and can disrupt the circadian rhythm (otherwise known as our internal body clock) telling us when we need to be awake and when we need to sleep. Darker evenings also tell the body to produce melatonin (the sleep hormone) earlier so we feel tired and ready for bed.”

Do we really need more sleep during the colder months? Here's why you're more tired in the winter