The overlooked sign you could develop dementia – and how your watch could spot it

This is Everyday Science with Clare Wilson, a subscriber-only newsletter from The i Paper. If you’d like to get this direct to your inbox every week, you can sign up here. Most of us are aware that, to look after our hearts, we should keep an eye on our blood pressure and cholesterol levels. But there’s a third aspect of heart health that gets less attention: how regular the heartbeat is. Heart rhythm irregularities affect a third of people at some point in their lives, usually taking the form of atrial fibrillation, or afib for short. Depending on severity, the condition can place people at a higher risk of stroke and dementia. Fortunately, afib can be can be treated – but it often goes unnoticed until it is too late. That’s despite the fact that there are an increasing number of ways to detect afib, from smartwatches to newer blood pressure machines. People can even detect it simply by feeling their own pulse. People just need to be aware of the condition and its risks to avoid the horrible health consequences, says Professor Gregory Lip, a cardiologist at the University of Liverpool. “We can reduce this progression to strokes and dementia.” Increased risk of stroke and dementia The heart’s ability to beat, non-stop, for two or three billion times in a typical lifespan, is one of the many amazing features of the human body. Heart muscle cells have such an intrinsic urge to beat that, even when they are grown on the bottom of a petri dish, they regularly contract and relax without prompting – something that left me in awe when I was first shown this while touring a stem cell laboratory.When in situ, the muscle cells of the heart’s upper chambers – the atria – should contract in synchrony to send blood into the heart’s lower chambers. But in atrial fibrillation, the muscle cells lose co-ordination, and the atria start quivering chaotically, or fibrillating. During a period of afib, the heart’s lower chambers can still manage to pump blood around the body, but they work less effectively. Afib happens when there is disturbed electrical activity in the heart’s two upper chambers (Photo: Getty) This might cause weakness, breathlessness and palpitations – feelings of fluttering in the chest or a faster or slower heart rate. Typically afib starts off happening occasionally and lasts only seconds, gradually getting more frequent and lasting longer over the years. It is more common in older people, but can begin at any age. The chief harm is that, while the atria are quivering, blood can linger there and form clots. These can travel through the circulation and, if they reach the brain, cause a potentially devastating stroke. Afib can also cause longer-term harms. Tiny clots can trigger more minor damage to the brain, which slowly builds to become vascular dementia. And over the years, the repeated bouts of afib may also weaken the heart, leading to heart failure. A missed condition There are several treatments, including taking blood thinners to cut the stroke and dementia risk and medicines to steady the heartbeat. People can also have a kind of minor surgery where the heart cells that set off the faulty rhythm are killed. This might sound drastic, but only a small number of cells need to be destroyed, and the procedure is done without having to perform open-heart surgery; instead, a long wire is threaded up into the heart from the groin. So, the more people who recognise that they have afib, the more we would reduce many avoidable cases of death and disease, says Lip. There are about 1.5 million people in the UK with diagnosed afib, but it is thought there are another half a million with the condition who don’t know it. Doctors have been debating whether there should be systematic NHS screening for the condition in people over a certain age, as there is for high blood pressure and cholesterol. A large trial has been assessing whether asking people over 70 to record their heart rhythm at home, and then offering treatment for those identified with afib, will cut the number who end up with strokes, heart disease or dementia. For this trial, people used a small device that can measure the heart’s electrical activity when both thumbs are placed on a button. They had to use it four times a day for three weeks. We should find out the results in 2028. In the meantime, growing numbers of people are discovering they have afib through their smartwatches. ‘I thought I hadn’t had enough sleep’ Millions of people now use these wearable devices, either for fitness or health reasons, or as an extension of their phone. Many of the more recent models include automatic heartbeat tracking, which can detect possible rhythm abnormalities. They are not good enough to give someone a clear diagnosis, but they can alert the user of possible afib. Heather Armstrong received such an alert from her Apple Watch in 2020 after a bad night’s sleep, when she was 55. “I felt palpitations, a bit of a fluttering in my chest, and I felt very tired and just not well, really. Because I hadn’t experienced it before, I thought I just hadn’t had enough sleep.” Heather Armstrong discovered her atrial fibrillation because of an alert from her smartwatch (Photo: H. Armstrong) Convinced it was a mistake, Armstrong went to hospital, but there they monitored her heart and told her she was having afib. In time, she had the surgery and now remains on blood-thinning medication in case the condition comes back. Armstrong is very glad her watch picked up such a treatable condition. But some doctors say smartwatches detecting afib has potential downsides too. The chief worry is that we actually don’t know how common or serious it is for people to have occasional bouts of afib. Previously, people would tend to notice only if the fibrillation persists or starts happening more often. “Watches might be finding a very small blip that doesn’t have an impact clinically,” says Dr Rakesh Modi, a GP and researcher at the University of Cambridge. He has seen a steady rise in the number of people coming into his practice after a watch alert about possible afib in the past few years. They get sent to hospital for investigations, which typically involve wearing a chest monitor for two weeks, which has higher accuracy. Often this does not detect any afib over this period – but that may not leave the patient reassured. “They sit there with a worry that they never would have had,” he says. As well as anxiety from false positives, Modi says health alerts from smartwatches and other similar tests are creating a burden on the NHS. Using watches for afib detection is a form of health screening – as are campaigns to persuade everyone to check their pulse, to detect afib that is not causing any physical symptoms. One such campaign, called “Know Your Pulse”, begins next week, promoted by the patient charity, the Arrhythmia Alliance. Modi says a potentially more useful campaign would be to focus on people who notice they have occasional heart palpitations, and encourage them to see their GP. In many cases, palpitations are caused by nothing serious – perhaps too much coffee or poor sleep, he says. But in some it will be caused by afib. And it could save that person’s life. I’ve also written Fruit juices and smoothies are often seen as health foods. But a new Government report has said they contain the worst kinds of sugars for causing weight gain and tooth decay. Called free sugars, these are created when sugar is extracted from plant cells. But doctors are still debating why they are linked with obesity and poor health. I’ve been watching This week I saw the eye-opening and eye-watering BBC documentary Manhood, about the new trend of men getting facial fillers injected into their penises. But sometimes the procedure goes wrong. Not for the squeamish.