I’m 56, going on 57, and am starting to feel some of the physical effects of my advancing years. I won’t bore you with the details, but suffice to say, none of them is a barrel of laughs.

I’m also starting to subtly notice one of the other negative effects of ageing, namely ageism. Nobody has openly insulted me yet, but I increasingly pick up hints that younger people regard me as past it, a has-been, an old fella. If the evidence is to be believed, it’s only going to get worse. In the US, for example, a study of 1915 adults aged 50 to 80 found that almost all of them routinely experienced age discrimination. Two-thirds of the group had regularly seen, heard or read ageist stereotypes, such as jokes at the expense of old people. Roughly half experienced ageism in their interactions with others, such as the assumption that they are hard of hearing, can’t use technology, don’t understand or remember things and need help when they don’t. The older people get, the more they encounter these prejudices.

Perhaps most surprisingly, the vast majority – over 80 per cent – had experienced a third form of ageism, “internalised ageism”, which means having negative expectations about one’s own mental and physical health as we get older. This is ageism against yourself.

These three forms of ageism are extremely pervasive, at least in Western societies. All told, only 6.5 per cent of people in the study had never experienced any of them. I suspect they were at the younger end of the demographic.

Ageism in any form is pretty troubling, but internalised ageism especially so. In recent years, it has become abundantly clear that this form of ageism is itself an amplifier of the ageing process. According to Becca Levy at Yale School of Public Health in New Haven, Connecticut, there is an “extensive body of… research” showing that people who hold negative beliefs about ageing tend to age less well.

For example, a recent study led by researchers at Harvard University found that older people with the highest levels of positivity about ageing experienced slower physical, mental and cognitive decline, ate better and exercised more than those with the lowest levels –internalised ageism at work. And it wasn’t that people who were already ageing badly were more negative: people’s attitudes at the start of the study predicted their subsequent trajectory. The mechanism is not clear, but the take-home message is that holding negative attitudes to ageing will make you age faster.

Levy has similarly found that people over the age of 65 who develop mild cognitive impairment (MCI) are much more likely to recover if they have a positive outlook on ageing. It was already known that around half of people with MCI get better. What Levy discovered is that a large majority of those who do are relaxed about ageing.

The overall impact of these negative attitudes is staggering, individually and collectively. Levy’s group recently published a model showing that each year, among Americans aged 60 or over, ageism directly leads to 3.2 million extra cases of the eight most budget-sapping diseases of old age at a cost of $11.1 billion.

The conclusion from all of this is obvious. Internalised ageism is a massive, under-recognised health problem that costs individuals and health services dear. According to Levy, it is a public health crisis.

Where ageism starts

Internalised ageism doesn’t just come from within. The three forms of ageism are mutually reinforcing. When older people encounter any of them, as they (or should I say we?) constantly do in personal interactions, entertainment, advertising and even in interactions with healthcare professionals, we internalise it.

This remorseless onslaught of negative stereotypes has a name: institutional ageism. Like institutional racism, it is pervasive in many cultures but flies under the radar. As the World Health Organization said in a recent report on ageism: “Often people fail to recognize the existence of such institutional ageism because the rules, norms and practices of the institution are long-standing, have become ritualized and are seen as normal.”

I hardly need to point out that ageism is a self-defeating form of prejudice. We all get older every day, and many of us will make it to old age. A young ageist today will eventually be hoist by their own petard (if they make it that far), trapped in a world of ageism that they helped to create and maintain.

There is a solution (or at least a partial one) at hand. Back in 2014, Levy and her colleagues showed that attitudes to ageing can be improved with subliminal messaging about the positive sides of getting older. But rolling these out on the scale required would be a gargantuan undertaking.

As the long-standing fight against institutional racism shows, fighting deep-seated prejudices is the work of decades – and inevitably endures setbacks along the way. I probably won’t live to see the day institutional ageism is finally banished. But I’m not going to let it get me down. Instead, I’m going to try to make my own ageing process a barrel of laughs.