Vests that can detect heartbeat and activity rates are to be tested on patients to see if they can be monitored from home and so reduce hospital check-up visits.

The 'life vest', which can be worn under normal clothes, transmits data continuously which can be analysed by computer and reported to doctors. Using 10 patients as guinea pigs, a trial is to begin at Oxford's John Radcliffe Hospital next month. If doctors can access data easily - over mobile phones or with hand-held monitors - it could be a huge saving for the NHS, say the device's developers.

Staff could check on patients who have diabetes, heart failure or lung disease, rather than having to ask them to attend outpatient clinics. It would also alert them to serious symptoms as they developed. The vests, made in China, are fitted with sensors which record heart rhythm, breathing rate and activity. They also have lightweight recorders to store data, which is sent to a monitoring centre in Oxford for analysis.

Clinicians could access data that would include graphs or patient reports. If they see problems they will be able to change prescriptions or provide lifestyle advice. The vests is that they can provide monitoring while patients are asleep, when breathing difficulties often arise.

'We are really excited about the prospect of transmitting data ... because it will be so fast and accurate,' says Dr Paul Johnson, an Oxford University physiologist and director of Xenetec, which has developed the vest. 'We can produce graphs and pictures to explain the information to the patients in a way they understand.'

Monitoring vests are used in the US but cost around £15,000. The Xenetec ones are expected to be marketed for about £100.

The idea is to keep patients away from hospitals, where they are more likely to pick up infections. Other schemes have shown that X-ray images and data from heart monitors can be assessed thousands of miles from the patient.

Jonathan Bryant, chief executive of Medify Solutions, which has linked up with Xenetec to transmit the data, says: 'We want to improve the way patients with long-term conditions are managed. If it keeps people out of hospital, that's a very positive advance.'