IT COULD be one of the most revealing medical tests you have taken, but at least it will certainly be one of the easiest. On Thursday, York Hospital is inviting you to come and blow down a tube into a machine called a spirometer.

No, I had never heard of them either, until I went along to take a test myself last week. You see, a spirometer, or the results it provides, gives doctors a comprehensive picture of the health of your lungs, and even a fairly reasonable idea of how long you can expect to live.

The usefulness of this ingenious instrument at spotting potential or undiagnosed lung problems means that it could save the NHS a lot of money treating people with chronic chest complaints.

On the day I turned up for my test I was still trying to shake off a nagging cold, so I was unsure of how my results would turn out.

I was welcomed by the hospital’s chief respiratory physiologist, David Lonsdale, who talked me through what would happen.

“We take your height and weight and make sure you’re fit enough to go through with it. Then we take the test.”

So far so good. For the test itself, I was asked to sit in a small plastic booth and then I had to put a clip on my nose to make sure the only air which went into the spirometer was from my mouth.

Now the hard bit. David told me I would need to take a deep, deep breath then blow as hard as I could in to the tube, until he told me to stop, then I would need to take sharp inhalation.

So…deep breath…and OUT. I blew and I blew, until I was finally given the signal from David to stop.

After breathing in again via the tube, the test was over. The machine then prints out a series of expected results and actual results, for your height and weight, of things such as lung capacity, litres of air per second.

Thankfully, all my results were fine. In fact, they were at the upper end of what would be expected and I was heartened to learn that the results could mean a long life.

David said: “Results are assessed and then the information is sent to your GP, and if there is an abnormality you would be given advice on what to do.

“The spirometer will tell us a lot of things – you can recognise most lung conditions with this.”

Dr John White, consultant physician, also seemed reassuringly pleased with my figures.

“If you have good lung function it’s a very good indicator of longevity,” he said.

When asked how to make sure your lungs stay healthy, Dr White’s answer will be of little surprise to anyone.

“Clearly, smoking is an important thing. Your occupation is another area where people may be exposed to fumes or dust and I would recommend using good protection.

“Stay fit and active,” he said. “We see people who get breathless with little exertion so they give up exercise and that just means their breathlessness will get worse.

“Try jogging, walking or whatever you can do to keep active.”

Tests are available at the hospital on Thursday between 9am and 4.30pm. No appointment is necessary.