Brain fog is on the rise. This is the worrying reason why, what it means for your health… and how you can fix yourself in less than a month. Our leading experts reveal their shock discovery

Sharan Kuar realised that her brain fog had become an inescapable problem when she began to forget what day of the week it was.

A former high-flying banker, the mother-of-two previously felt as though she had boundless energy, allowing her to effortlessly juggle her career and home life.

However, in 2020, during the first Covid lockdown, things began to shift.

At the time, Sharan had made a career change – setting up her own financial advisory business – and she began to work from home.

‘That’s when I began to notice the brain fog,’ she says. ‘I needed to be on the ball at all times, remembering complicated financial figures. However, I started to forget the simplest things. I would read a book or watch a TV programme, and then afterwards realise I couldn’t recall a single detail.

‘I would go to the supermarket and realise I couldn’t remember what I’d gone there to get.’

The problem got so bad that even her children, aged nine and 11, noticed something was wrong.

‘I would have to ask them what day of the week it was,’ says Sharan, now 44. ‘Sometimes I wouldn’t even know it was the weekend. I just couldn’t retain any information, it was terrible.’

She is far from alone. Brain fog is typically understood as a range of cognitive symptoms including poor concentration, confusion, slower thinking and forgetfulness.

In the past, experts rarely treated brain fog as an individual problem, but as a symptom of other medical conditions. However, growing research shows that it is not only a distinct medical problem with clear characteristics, it is also on the rise.

A recent landmark medical study of British adults found that about a third now regularly suffer from brain fog. Crucially, many of them have no underlying health problems that could be the cause of the cognitive issues.

Now experts believe they know what is causing it as well as the steps patients can take to banish the problem in less than a month.

The first step is to rule out any undiagnosed medical problems that could be causing the symptoms, says Dr Oliver Bernath, a consultant neurologist at Guy’s and St Thomas’ Hospital and the Reborne Longevity clinic.

‘When GPs refer brain fog patients to my clinic, we always make sure diabetes and thyroid problems have been ruled out first,’ he says.

‘These are conditions that can be diagnosed with blood tests and treated with medication.’

Another condition that is strongly linked to brain fog is the menopause. Studies show that two-thirds of women suffering from the mid-life hormone changes will experience it.

The good news is that prescription hormone replacement therapy, also known as HRT, can usually reduce brain fog.

Long Covid can also trigger brain fog. Experts say this, in part, explains the rise in sufferers in the UK in recent years.

There is no cure for the long-term after-effects of the virus, but evidence shows that gentle exercise may improve symptoms.

However, there are also millions of UK patients who suffer from brain fog but have none of these underlying issues.

According to a 2024 study of about 25,000 UK patients, those with no clear cause of brain fog tend to share the same characteristics: they are more likely to be women aged over 35 and less likely to sleep well or regularly exercise. But experts say the primary cause of brain fog is the amount of time we spend on our digital devices.

‘We’re all multi-tasking all the time – our brains were never designed for this,’ says Dr Bernath. ‘We are on our phones constantly, often while we’re doing other tasks, like watching TV, shopping or working.

‘Each time we turn our attention to something new, we get a dopamine rush [a feel-good chemical]. But, over time, this can tire out the brain.

‘That’s why I see so many women in their 40s with brain fog. They often have successful careers and a happy family, but as they get older all this multi-tasking begins to wear them out and they start to get cognitive issues.’

Avoiding screens before bedtime and going to bed and waking up at roughly the same time improves sleep quality and combats brain fog, says Dr Bernath.

Regular exercise has the same effect, as well as taking up hobbies such as playing an instrument or learning a language, he adds.

‘These are tasks that you have to give your full attention to,’ he says. However, the most important factor in reducing brain fog is an active social life. ‘All the research shows that people who regularly socialise have healthier brains.’

‘You don’t need to do anything special. Simply sharing a meal with someone once a day can be enough,’ Dr Bernath adds.

For Sharan Kuar, from Wolverhampton, the answer was a combination of improved sleep, more exercise and better diet.

‘One day I realised I needed to improve my lifestyle,’ she says. ‘Not just because of the brain fog, but also because of my overall health. I realised I wasn’t taking good care of my body.

‘My diet and sleep were terrible, and I barely exercised. So, last year, I changed my bedtime from 11pm to 9pm, cut down on unhealthy foods like sugary tea and cheese on toast, and began doing 15-minute home workouts five times a week before the kids were awake.

‘Within a few weeks, I began to notice a real difference. I realised I was remembering dates and details from the books I was reading better. I didn’t need to take a shopping list to the supermarket.

‘When I had the brain fog, I felt unproductive and lethargic. Now I feel so much better – it’s like I have the brain of a 20-year-old.’