They used a TENS machine – more commonly used for muscle pains or to help women in labour – to stimulate a small area at the front of the ear called the tragus. They say this is painless (Professor Jim Deuchars, from the university’s Faculty of Biological Sciences called it ‘a tickling effect’) and that it appears to have an effect on the heart.
They trialled the TENS on 34 healthy people for 15 minutes each, monitoring their heartbeats and nervous systems while the machine was on and for 15 minutes afterwards. They found that the subjects’ heart rates become more variable – this being a good sign, as a too-regular rhythm can mean a heart is working too hard.
They also discovered that the stimulation seemed to calm the sympathetic nervous system, reducing adrenaline, which, in excess, can cause arteries to narrow, leading to long-term damage. These positive effects continued after the machine was switched off.
The effectiveness of this technique is probably due to the fact that it stimulates a major nerve, the vagus, which runs to vital organs, including the heart. It’s so far only been trialled in people with no history of disease but the Leeds team is hoping it could one day help patients with heart failure, and are planning to start clinical trials as soon as possible.
Image credit: University of Leeds.