A good night’s sleep, regular exercise and drinking a small amount can help the brain ‘clean’ itself at night and protect it against Alzheimer’s, say scientists.
All three activities stimulate the brain’s glymphatic system, which wipes away the toxic build-up of proteins linked to the devastating disease, according to researchers.
The studies on mice represent a breakthrough as they could help illuminate how the human brain functions – including how it clears away its waste products.
Dr Ian Harrison, of University College London, told the Cheltenham Science Festival that studies on the brain and spinal fluid of mice had shown that sleeping well, increasing heart rate through exercise and 25ml of wine per day stimulated the self-cleaning mechanism.
And he said researchers were now focusing on finding ways of preventing the human brain’s glymphatic system from failing.
Dr Harrison said: ‘A paper came out a couple of years ago where the researchers studied the brains of mice when they are asleep and mice when they are awake.
‘What the researchers did was inject a dye into the cerebrospinal fluid and see where it goes.
‘In the mice that were awake, that cerebrospinal fluid starts to go into the brain but only resides on the surface and doesn’t go deep into the brain tissue.
‘In the same animal when it fell asleep, that cerebrospinal fluid goes far deeper into the brain.
‘When they quantified this in the animals that were asleep, this glymphatic system was far more active – 60 % more than in the animals that were awake.
‘This is good evidence that the glymphatic system is active during sleep. If that is anything to go by we should all be sleeping a lot more than we are.
‘That kind of makes sense because, if you think about it, when your brain is active during the day these brain cells are going to be actively producing all these waste products, so it is only at night when our brain switches off that it has the chance to switch on our glymphatic system and get rid of all these waste products.’
He said there were similar results with exercise, adding: ‘In the sedentary animals, the fluid penetrates the brain but when the animals have voluntary access to exercise there is massive increase in the amount of glymphatic function.’
It is thought the increase in heart rate helps drive cerebrospinal fluid into the brain.
The scientists also gave mice low, intermediate and high doses of alcohol for 30 days.
Dr Harrison said that with low doses – the equivalent of a third of a unit a day, or 25ml of wine, for a human – resulted in a 30 to 40 per cent increase in self-cleaning.
However, intermediate and high doses led to a reduction in self-cleaning by a similar percentage. Dr Harrison added: ‘So, sleep more, exercise and, as the data suggests, you can have a drink, but only a third of a unit of wine per day.’