Avisitor to the computer room at Plessington Catholic high school technology college, the Wirral, might come across an unusual sight. Twelve students sit before their screens, eyes half-closed, hands on hearts. They are breathing evenly and regularly. The observer might notice a wire snaking from each machine to a plastic sensor attached to one of their fingers.

The students have been practising a powerful relaxation technique called heart rate variability (HRV) training that has been having a remarkable effect on the way pupils and teachers handle stress. What makes the experiment unusual is the use of computer software that links the activity of the heart with pupils’ emotions. “I get really stressed out,” says deputy head girl Lindsey Furlong. “I’ve always hated exams. A while ago I got so stressed I developed alopecia. I wanted to learn to drive, but the idea of driving lessons was too alarming.”

All that has changed for Lindsey as she has learned how to control the rhythm of her heart. The sensor on her finger records her pulse while a computer program transforms the information into a pattern of lines on the screen. By concentrating on positive emotions of affection and appreciation, she can change the variability of her heart rate - the HRV.

The technology Lindsey and other sixth-formers and staff have been using was developed by a Californian institute called HeartMath. Rather than simply measuring pulse rate, it tracks the changes in time between each heartbeat. It is based on a belief that the heart is controlled by two arms of the central nervous system - the sympathetic and the parasympathetic.

The former controls arousal responses - increasing heart and breathing rates and narrowing blood vessels, while the latter reverses these changes.

A healthy person constantly switches between the two - giving a high HRV - because we need both. Getting stuck in relaxation or arousal - having a low HRV - is dangerous.

The program is a bio-feedback tool that teaches users to take control of their HRV and counter stress by focusing on positive emotions.As Lyndsey concentrates, the pattern on the screen in front of her becomes increasingly rhythmic and coherent.

“It took about 20 minutes a day for a month before I started noticing the changes,” she says. “Then the effect was amazing. The other day I did my art A-level, which is pretty stressful. You have to stand most of the time and I was dreading it, but I used the HRV technique at the beginning and I enjoyed it. I felt very relaxed. It was the best exam I’ve ever done.” Now she’s learning to drive.

In recent years more than 6,000 UK executives have been taught the technique to help them handle stress. Last year, a study reported in the Journal of Complementary and Alternative Medicine found that executives on such a training course reported a 36 per cent reduction in stress symptoms and that the blood pressure of those with hypertension - almost one in three - returned to normal.

The Plessington experiment is the first time the software has been used in a British school. Recent reports about high levels of teacher and pupil stress suggest it’s a timely initiative.

“When I read about the technique, it seemed too good to be true” says Tony Lloyd, a psychotherapist and Plessington’s student support services manager. “But we have had such significant results with HRV training that next September we want to make it available for all the kids in school with challenging behaviour during their learning support session.” There are also plans to run training sessions for local schools that are interested.

The introduction of the system last May was made easy by the fact that both Mr Lloyd and headteacher AdrienneBurns discovered it independently. Mr Lloyd heard good reports from a US psychiatrist who had used it to control an irregular heart rhythm, while Miss Burns was told about it by deputy headAlan Lee, whose wife, had been studying it as part of her work as a researcher at nearby Liverpool University. The clincher was when it emerged that Unilever, which has strong connections with the school, had given HRV training to its executives. Hunter Kane, the firm involved in that training, agreed to give an introductory session to the school.

“I was sceptical,” admits assistant headteacher Martin Kane. “It all sounded too Californian, but now I find it a great way to unwind at the end of the day - much more effective than a stiff whisky. It’s also good when you are stuck in traffic and start to steam up. Life can be tense at school and this is a useful tool to help you handle it.”

For years researchers have been coming up with evidence that positive emotions make people healthier and function better, but no one really understood why. The HeartMath link goes some way to explaining the phenomenon, and provides scientific support for the poet’s insight about the link between the heart and love.

The value comes with being able to use the techniques in daily life. “Once you can shift your HRV to an optimum rate, you can apply the techniques as soon as you spot a situation is getting stressful,” says Tony Lloyd.

“Usually at this point, hormones released in the body speed up your heart rate, and your stress responses kick in. You start thinking less clearly and you feel angry or anxious.

“The idea is to fuse your reasoning and your emotional sides so they work together,” explains Mr Lloyd. “You can put yourself into a sort of neutral gear where, instead of being taken over by your usual stress response, you can ask yourself what is best way to respond. Suddenly you realise you have choices.”

The same is true of how Plessington plans to use HRV. Besides expanding training to pupils with behavioural problems, the school intends to use it as a teaching tool in biology. “It certainly made me want to know more about the links between my brain and my heart,” says Lindsey. But right now what everyone is waiting for is to see if it has given them an edge in the exam results.

For more details on training and HeartMath: www.hunterkane.com