They say you're only as old as you feel – but hitting 62 means you're officially getting on, according to Gen Z.

A poll of 4,000 people across the UK has revealed how different generations perceive ageing.

While Boomers (born between 1946 and 1964) think old age begins at 67, their children and grandchildren believe it to be much younger.

According to Gen Z, the likes of Michelle Obama, Brad Pitt and Lisa Kudrow – who are all 62 – have officially fallen into the 'over the hill' category.

The polling also revealed Gen Z think people start experiencing cognitive decline at 62, while the struggle to adapt to technology begins three years earlier at 59.

Meanwhile, they believe someone no longer looks good wearing the latest fashions at 56.

Katherine Crawshaw, co–head of the Age Without Limits campaign, said: 'What we often see with beliefs around age and ageing is real concern at becoming older, of reaching a certain age, from quite early on in our adult lives.

'And then as we reach those milestones, for many the fears and worries about reaching that age dissipate somewhat with the reality. Being subjected to a barrage of ageist messaging throughout our lives, with children as young as 10 wanting to buy anti–ageing make–up for example, gives people an unduly pessimistic view of what getting older will be like.'

Analysis of the data also revealed that a fifth of Gen Z–ers, who are aged 18-29, don't think they'll look good when they're 'old'.

Meanwhile a quarter don't expect to still have plenty of family or friends around them in their later years.

Some 27 per cent don't think they will be in good health when they are 'old' and are likely to believe people have less fun as they age.

Across all people polled, the most common phrase used in reference to an older person was 'stuck in your ways', followed by 'mutton dressed as lamb'.

Other popular phrases included 'you're too old for that', 'dinosaur' and 'over the hill'.

The data revealed that a significant proportion of Gen Z were likely to think people over the age of 50 will struggle to keep up with technology.

However, they appeared to have a more sympathetic view on the value of older workers compared to Boomers and were more likely to think that, overall, people at this age would still be a desirable hire for employees.

The 'Age Without Limits' campaign, run by the Centre for Ageing Better, aims to highlight the harmful nature of ageism across all aspects of society.

Harriet Bailiss, co–head of the campaign, said: 'Taking a simplistic view of ageism, one might assume that younger generations are likely to hold more dismissive opinions of older age. 

'The reality is much more complex than that, as our latest polling shows.

'While the figures might indicate a potential frustration with older peoples' use of technology from younger generations, it also seems to indicate that Gen Z have a more hopeful view around older workers and employment than the Babyboomers themselves who are trying to navigate an ageist labour market.'

She added: 'What we know is that ageism can impact people at all ages and many Gen Z–ers will have experienced being judged on their capability based purely on their age.

'This is why we need everyone, no matter their age, to be able to notice ageism and to challenge it when they do witness it.'

Last year, scientists discovered the average human life is split up by four pivotal 'turning points' between five key stages.

These are childhood, adolescence, adulthood, early ageing and late ageing.

Analysis of the brain scans of 3,802 people aged between 0 and 90 revealed it takes almost three decades of rewiring before our brains reach their adult forms.

Once we reach our mid–30s, our intelligence and personality reach a stable 'plateau'.

However, it all goes downhill from age 66.

At this age, our brains stop becoming more efficient, and the structure stabilises with more 'segregation' emerging as regions start to become more compartmentalised.

Based on previous studies, the researchers say that this corresponds with a 'plateau in intelligence and personality', although the reasons for this change aren't entirely clear.