A good nights sleep begins with healthy gut bacteria. Heres how to look after yours

It’s no accident that we spend a third of our lives asleep. It is essential to our health, and even animals for whom resting is complicated – such as aquatic mammals that need to surface to breathe, or birds that go up to 10 days without touching dry land – manage to sleep with surprising adaptations. But while we sleep, the tens of trillions of microorganisms that live within us – known as the microbiota – follow their own rhythms. This microscopic colony, composed mainly of bacteria, can weigh as much as 200g. Together with its host, it forms a biological unit known as the holobiont. The microbiota is not just a passenger. Within each person’s body it comprises a functional unit, one that influences vital processes such as digestion, immune function and, as we will see here, sleep. Our relationship with the microorganisms we harbour is also deeply interdependent. Not only do we provide them with a place to live, but we also depend on them to maintain numerous biological functions. This delicate balance is increasingly being linked to health, wellbeing and, quite possibly, to longevity. Read more: What the gut microbiome of the world’s oldest person can tell us about ageing A two-way relationship As with many physiological processes, the relationship between our microbiota and sleep is bidirectional. In other words, your microbiota can influence how you sleep, but a good night’s sleep is also vital to maintaining a diverse and balanced microbiota. When it is healthy, the microbiota produces, among other substances, short-chain fatty acids such as butyrate. These molecules are associated with reduced inflammation and improved functioning of various neuroendocrine pathways, including the hypothalamic-pituitary-adrenal axis, which regulates the body’s stress response. Proper functioning of this system can help reduce night-time cortisol levels, resulting in deeper sleep and fewer awakenings during the night. Read more: Is lighter sleep a normal part of ageing – or a sign of something more serious? Furthermore, the gut microbiota is linked to the production of neurotransmitters such as serotonin, which is associated with positive mood states. How to get a better night’s sleep: 3 tips There is no such thing as the perfect microbiota, as each person has their own unique microbial ecosystem. The key is to maintain a functional balance and, should any imbalance arise, to remember that improvements are usually achieved through gradual lifestyle changes. To this end, here are three ways to help improve the relationship between sleep and microbiota: 1. Fill your plate with fibre: Diet is key, as a well-nourished gut microbiota reduces body inflammation and improves sleep quality. Vegetables, fruit, pulses, whole grains and fermented foods such as yoghurt, kefir or fermented cabbage (sauerkraut, kimchi) feed the beneficial bacteria in the gut. The Mediterranean diet is particularly beneficial for microbial diversity. Reducing the consumption of ultra-processed foods also helps to maintain the balance. 2. Stick to a regular schedule: Exposure to natural light, especially in the morning, is another key factor. Light acts as a fundamental signal for synchronising your circadian rhythm. Reducing exposure to bright artificial light at night can improve sleep quality and help keep biological rhythms in balance. Getting enough good-quality sleep isn’t just about resting – it’s also a way to maintain balance in the microscopic ecosystem that accompanies us throughout our lives. And that balance can, in turn, have a profound impact on our physical and mental health. Just a few days’ sleep deprivation can alter the composition of the gut microbiota, increase inflammatory responses, and lead to increased intestinal permeability. It can even alter the body’s response to glucose the following day or an individual’s cognitive ability. 3. Get moving every day and manage stress: Regular exercise is linked to greater microbial diversity and more restful sleep. And it doesn’t need to be intensive training: walking, cycling or swimming are all beneficial. And while it may not be the easiest thing to achieve in modern societies, it is important to manage stress effectively. Practices such as conscious breathing, yoga, meditation or mindfulness can help to reduce it. So can simple activities such as maintaining meaningful social relationships or taking a walk in nature. Reducing stress not only benefits your mental health, but also the health of your gut microbiota. This, in turn, has a major impact on the quality of your sleep.