ELDERLY passengers, longer flight times and poor-quality cabin air are behind a rise in the number of inflight medical problems, a new study has found.

ELDERLY passengers, longer flight times and poor-quality cabin air are behind a rise in the number of inflight medical problems, a new study has found.

However, travelling in economy class rather than business class does not increase the likelihood of medical trouble, the research shows.

Dr Mark Gendreau, writing in The Lancet medical journal, warns that the growing number of older passengers on commercial flights has meant more people are travelling with pre-existing medical conditions. This in turn has led to growth in the overall number of "medical events" occurring on aircraft, he and his colleagues said.

The research showed people older than 70 were more likely than others to suffer health problems on board aircraft.

Travellers boarding flights with pre-existing cardiac, pulmonary and blood conditions are far more likely than their healthy companions to suffer adverse effects during flight. Cabin pressure at cruising altitude causes gases in the body to expand by 30%, which is not a problem for most people but can cause serious problems for others.