I am aware, in theory, that the seasons change. But the endless darkness of UK winters never fails to take me, or my sleep schedule, by surprise. I have begun “drockling” . My 3am wake-ups have increased. And though I ought to know better , I’ve been struggling to relax when they occur – paradoxically, stressing about the perfect night’s sleep keeps me up all night . But are these true red flags, or just normal sleep fluctuations? Speaking to HuffPost UK, Hannah Shore, the Head of Sleep Science at Mattress Online , said: “Many different things can affect sleep, from daylight exposure to stressful events and even the temperature of the room. So when we have periods of sleep that aren’t as good as we get on average, this is completely normal. “However, there are certain things we should be keeping a closer eye on to ensure that your sleepiness isn’t actually an underlying sleep disorder.” Here are four signs she says she’d never ignore: 1) Prolonged sleep difficulties “If your sleep issues are lasting for a long period of time (three to four times a week for around three to four months)... something out of your control may be going on, and you may want to speak to a medical professional,” she said. This is in line with a doctor’s “3-3-3” rule , which suggests bad sleep for at least three nights a week over three months or more is worth investigating. 2) Snoring Shore isn’t just talking about “purring” here, but “loud and irregular noises,” which are “accompanied by moments of paused breaths whilst sleeping. “These are key signs of obstructive sleep apnoea [ OSA ], a sleep-related breathing disorder which is becoming increasingly more prevalent and can be treated with medical help,” she continued. 3) Vivid and often frightening dreams You might be as surprised as I was to learn that restless sleep and even nightmares have been linked to dementia risk. Shore added that there are many other causes behind dreams “where you wake and feel very emotional and [which] can affect your ability to fall asleep,” too. “If this is happening frequently, then this could be a sign of parasomnias and treatment to find out the cause/trigger will be needed,” she advised. 4) Impaired daytime functioning Insomnia is often measured not by how you feel at 2am, but by how your day’s going at 3pm. After all, Shore explained, “even though you think you are getting a good night’s sleep, you [may still be so] tired, it is affecting your ability to complete certain daytime tasks. “This could be struggling with energy levels, memory or motivation. It could also include things like headaches and mood changes,” she said. The issue doesn’t only point to insomnia, either. Struggling in the daytime “indicates that even though you may be sleeping for the right amount of time, there could be something wrong with the type of sleep you are getting, pointing to a potential sleep disorder which may need treatment.” Related... A Doctor Uses These 3 Numbers To Tell Bad Sleep From Insomnia The First Technique A Sleep Expert Tries After Waking Up At 3AM Sleep Experts Share Their Rules For Handling A 3AM Wake-Up