And just a third of those questioned thought heart disease was avoidable, even though obesity, inactivity, smoking and excess alcohol all contribute to the risk.
One in four had been urged to lose weight by a doctor or other professional, but two-thirds had never received such advice. Only one in six (13 per cent) had been told to lose weight and succeeded in doing so - while a further 16 per cent failed.
High blood pressure, which can lead to heart attack and stroke, affected 20 per cent of respondents.
But just 4 per cent had been diagnosed with heart problems, said the survey by the Simplyhealth Advisory Research Panel (ShARP), backed by healthcare provider Simplyhealth. Experts estimate that more than a third of men and 15 per cent of women aged 45 to 75 actually suffer from coronary heart disease, so many are not being diagnosed promptly.
They are calling for a 'reality check' so older people can cut the risk of age-related disease by changing their behaviour.
Research which measured a blood chemical linked to heart injury in 310 sedentary people in their 70s found levels were three times higher in those who refused to take part in a modest exercise programme.
Dr Catherine Hood, ShARP expert and associate specialist at St George's Hospital, London, said average life expectancy is now 78 for men and 82 for women, but official statistics estimate that someone who is now 65 will endure around eight years of poor health or disability by the end of their life.
She said: 'We all know health problems become more common as we age, but when it comes to wellbeing, thousands of us are putting our heads in the sand and are in a state of denial. Many of us as we age, according to our research, are avoiding vital health check-ups.
'We need to keep on top of our healthcare needs as we age and that starts with a reality check - having regular check-ups such as eye sight tests, so taking a preventative approach to managing our health, having an active, healthy lifestyle, plus a diet rich in nutrients.'
The survey found one in eight older Britons were put off having regular eye tests because of the cost, with one in ten saying deteriorating sight was 'an age thing'.
Dr Val Mann, senior lecturer in regenerative medicine at University Campus Suffolk and guest adviser to ShARP, said: 'There is now irrefutable evidence that we can reduce the risk of age-related disease by making healthy lifestyle choices and it is never too late to make these positive changes.'
- Daily Mail