Watching a video of my heart beating is as worrying as it is reassuring.
I am happy to see that it is steadily pumping blood around the body. But the clarity of the image carries an irrational fear - that if I hit the "stop" button on the machine, it might just halt the muscle mid-spasm.
As technology gives patients a better view of their insides, these feelings of fear and curiosity are likely to be something that more and more of us experience.
An increasing number of firms are offering this kind of high-tech medical check-up - although some critics claim they are a waste of money, and often show up problems where none exist.
One company that is hoping to tap into our growing interest in healthy living and disease prevention is Preventicum.
Originally set up in Germany, and now with a branch in west London, the company is marketing itself to patients with cash to spend - be they corporate executives or retired couples keen to stay in peak condition.
Get an inside-out view of the human body and its circulatory system of veins and arteries
For £2,750, a patient is put through five hours of testing that covers everything from cholesterol levels to bowel cancer, lifestyle choices to internal organ functions.
Spend a morning with the company and you can see where the money goes.
The clinic's rooms look like upmarket hotel suites, with branded tracksuits, computers and fresh fruit salads.
Clients are rotated from test to test so that they never meet in the spotless corridors, and results are ready by the end of session with a doctor on hand to explain what everything means - and whether or not extra treatment is required.
For Garry Savin, Preventicum's medical director, the benefits of health screening far outweigh any negatives.
"It's a no-brainer," he explains in between questions about how well I am sleeping and what diseases are killing off my family.
Unfortunately, not all current medical opinion shares Dr Savin's conviction.
"Some tests," says a recent report by consumer group Which?, "are likely to cause more harm than good, some give widely inconsistent results and little useful information, and some detect disease when it's not really there.
"False results cause worry, more investigations, and even unnecessary treatment - at a cost to the individual or the National Health Service (NHS)."
I'd rather know as soon as possible if there was anything wrong... I believe that screening saves lives
Garry Savin, Preventicum
One of the main complaints is the amount of radiation emitted when a patient is checked over by some types of body-scanning machine, which - it is argued - could actually increase the likelihood of contracting cancer.
Earlier this month, the Department of Health asked the Committee on the Medical Aspects of Radiation to assess the dangers associated with exposing healthy people to radiation-emitting CT scans.
CT scanning refers to a procedure that is also known as computerised or computed tomography, whereby a three-dimensional view of the body is constructed from a series of cross-sectional x-ray images.
On top of the radiation worries, there are also concerns about how the health-check test results may be used regarding a client's employment and insurance, and there are fears that unscrupulous operators may hard-sell expensive treatments.
In fact, the UK does not view separate check-ups as a key part of its drive to improve the nation's health, and says that if people have concerns then they can discuss the problems with their GPs.
Instead it plans to focus on getting people healthier by promoting better diet, getting them to use less alcohol and tobacco, and enjoying a more active lifestyle.
The Department of Health also points out that there is a big difference between a national health screening programme with proven results, such as testing women for cervical cancer, and health checks where data is less conclusive.
Testing can be hard work and is not always a pleasant experience
Regardless of the concerns, though, demand for check-ups is on the increase, according to health company BUPA.
The firm offers different products ranging from £250 to £900, and says that it has carried out more than 100,000 check-ups on people from "all walks of life".
Peter Mace, assistant medical director of BUPA Wellness, says he expects demand to continue growing because people are becoming more interested in their health at a time when state services are increasingly stretched.
Patients, he says, do not always want to bother their local doctor with questions about wellness as opposed to illness.
And while Dr Mace admits that the tests do throw up false positives, he counters that the key to a good check-up is how the doctors and medical staff explain the situation and treatment options to the patient.
'Given the choice'
At Preventicum, customer care is at the heart of how they market their services, and the company highlights its past successes - and the fact that its MRI scanner uses magnets rather than potentially dangerous radiation, to create its images.
Dr Savin does not see the company competing with the NHS - which offers patients care when they have already become sick - but wants it to provide services that complement state health care.
Ideally, Dr Savin hopes that patients will view their healthcare in the same way they do their life insurance and critical illness cover, setting aside monthly payments that will cover a full check-up every two to three years.
"If I was given the choice, I'd rather know as soon as possible if there was anything wrong," Dr Savin says. "I believe that screening saves lives."
And while many people may share his views, the success of companies like Preventicum is likely to depend on how willing patients - or their employers - are to pay for that extra peace of mind.