More than half of all Britons risk their lives and ignore the first signs of potentially serious illness, hoping they will simply go away.
According to a YouGov survey commissioned by private healthcare provider Bupa, two in five delay visiting their GP, even when they believe their symptoms could be an indication of serious illness.
One in three put off having such symptoms looked at because they do not wish to waste their GP's time.
Andrew Thom, 41, is a serving officer with the Metropolitan Police.
Fit, healthy, with no smoking habit and no love of alcohol, he chose to ignore bleeding for over a year, even missing an appointment for a colonoscopy.
An HIV test he received after performing CPR whilst on duty alerted him to his reduced haemoglobin levels - and, ultimately, a malignant tumour five centimetres from his anus.
He said: "I didn't know they were symptoms of bowel cancer. For about a year I was bleeding persistently, going to the toilet and noticing there was blood on the toilet paper and in the toilet.
"I personally thought it was piles. Being a typical heterosexual male, I just left it.
"Either I thought it would go away or I was too embarrassed to deal with it."
On learning of his diagnosis, Mr Thom began to feel angry.
He said: "Through my ignorance I thought that only unhealthy people suffered from cancer. I'm very sports-motivated, I don't drink or smoke.
"Because of the nature of my job I've always had a sports background.
"'Why should I have cancer,' I thought. 'It isn't fair, it can't be right.'"
Department of Health figures demonstrate that early diagnosis is hugely important, particularly in cancer cases.
DoH research shows that, where bowel cancer is diagnosed early, nine out of 10 early patients survive for at least five years, compared with less than one in 10 diagnosed late.
Whilst unexpected lumps or changes in the size and shape of a mole are well-known symptoms of serious illness - and more likely to prompt a trip to the GP - doctors insist that, if symptoms persist, you should seek help.
Dr Marie Tyrell told Sky News: "We are used to seeing and talking to people about everything and you will be listened to. We are quite happy for you to come and see us.
"Anything that's worrying you and lasts for more than three or four weeks and is persistent - come and ask us about it."
The research also found three in 10 delayed calling the doctor because it was difficult to make an appointment and more than half would not make an urgent appointment if they suffered a persistent cough for more than a few weeks.
Dr Annabel Bentley, Medical Director at Bupa Health and Wellbeing, said: "It is worrying that people put off seeing their doctor for worrying symptoms.
"It may turn out to be nothing, but seeing your doctor can help give you peace of mind.
"And, if the symptoms could be due to a serious problem, this allows you to discuss this with your doctor and work out the best plan of action together.
"Early stage diagnosis can be really important with some diseases, such as cancer."