Can Insomnia Make You More Likely to Catch the Flu? August 7, 2025 We all know the sniffles and sore throats that come with the flu are no fun. But did you know that how well you sleep might actually influence whether you catch the flu in the first place? Insomnia – especially chronic insomnia – doesn’t just leave you feeling groggy and irritable. Research now shows it could significantly weaken your immune system, making you more vulnerable to illnesses like influenza and other respiratory infections.1 What Is Insomnia? Insomnia is a common sleep disorder where people struggle to fall asleep, stay asleep, or wake up too early and can’t get back to sleep – despite having enough time and opportunity to rest.2 When this happens at least three nights a week for over three months and affects your ability to function during the day, it’s considered chronic insomnia.2 How Insomnia Affects the Immune System Sleep isn’t just for rest – it’s a vital time when your body gets to work, especially your immune system. While you sleep, your body releases cytokines – proteins that help regulate inflammation and immune responses.3 These play a key role in fighting infections. A lack of sleep disrupts this process, meaning your body might not react as effectively when it encounters a virus. Studies show that people who sleep less than six hours a night – or who suffer from insomnia – are not only more likely to get sick but may also have more severe infections.1 One large-scale study involving over 600,000 people found that those with diagnosed insomnia were nearly six times more likely to develop an unspecified respiratory infection and more than four times more likely to get the flu than those without insomnia.1 Even short-term sleep loss can throw your immune system off balance. In one experiment, participants who slept for just four hours showed a significant drop in their levels of natural killer cells – the immune cells that target viruses.3 Another study found a single night of poor sleep was enough to increase inflammation markers in the blood.3 Why Does This Happen? There are a few mechanisms at play. Firstly, sleep loss can reduce the ability of white blood cells to reach infected areas.3 It also increases stress hormones like adrenaline and prostaglandins, which lower the levels of integrin – a molecule that helps immune cells stick to and kill virus-infected cells.3 This means your body has fewer tools to identify and fight viruses effectively. It’s no wonder, then, that people with chronic insomnia are more likely to need antibiotics when they get sick – their immune system is simply struggling to keep up.3 Insomnia in Australia Insomnia is more common than you might think. Around 15% of Australians meet the criteria for chronic insomnia, and nearly 60% report frequent sleep symptoms like difficulty falling or staying asleep.4 These issues, if persistent, can lead to daytime fatigue, poor concentration, low mood, and, as we now know, a weakened immune system.2 Take Sleep Seriously If you’re tossing and turning most nights, it’s not just about being tired – your immune health could be at risk. Prioritising good sleep hygiene, creating a restful bedtime routine, and seeking help for persistent insomnia is essential. If you’re experiencing ongoing sleep issues, speak to your doctor. A good night’s sleep isn’t just a luxury – it’s a key part of staying well, especially during flu season. How Sove CPAP Clinic Can Help Founded in 2008, Sove CPAP Clinic has grown to become a leading provider of respiratory and sleep services and products in Australia, with over 60 clinics nationwide. Our comprehensive clinical team includes Respiratory & Sleep Specialists, Sleep Technologists, and CPAP Consultants, ensuring that you receive comprehensive and personalised care. All medical procedures, including sleep studies and lung function testing, are bulk billed to all Australians, with minimal wait time. If you would like to speak to a Respiratory & Sleep Physician, book a bulk-billed sleep study, or seek advice for your sleep apnea, you can reach us at 1300 76 29 39 or info@thecpapclinic.com.au. ALWAYS FOLLOW THE DIRECTIONS FOR USE. CPAP is used for Obstructive Sleep Apnea treatment. When considering whether a sleep study or CPAP is right for you, speak to your doctor. Medicare criteria and T&Cs apply. References News-Medical. “News-Medical.” News-Medical, 8 June 2023, https://www.news-medical.net/news/20230608/Insomnia-raises-the-risk-of-influenza-and-other-respiratory-infections.aspx. Accessed 6 Aug. 2025. “Insomnia - Definition.” Sleepprimarycareresources.org.au, 2016, www.sleepprimarycareresources.org.au/insomnia/definition. Accessed 6 Aug. 2025. “Too Much or Too Little Sleep Can Increase Your Risk of Getting Sick.” Healthline, 2 Mar. 2023, www.healthline.com. “Insomnia - Prevalence.” www.sleepprimarycareresources.org.au, www.sleepprimarycareresources.org.au/insomnia/epidemiology.
