Sneaky ways your body changes after you turn 60

When sales of adult nappies exceed sales of baby nappies, the western world is getting a clear message – there are more old people than young, and the oldies are determined to be just as active and socially acceptable as their children and grandchildren. Even if they wet their pants at unexpected moments, just like the infants they babysit for their sons and daughters.

In Japan, the United States and even Kenya, media report an unexpected surge in "adult incontinence products", mostly (but by no means all) for older people. Kimberley Clark estimates that one in three women and one in ten men have some form of urinary or faecal incontinence – women at the higher end due to involuntary weeing from pelvic floor muscles weakening after childbirth. As many ageing mums have found, a sudden sneeze can require a speedy leg-crossing or a quick trip to the loo.

But the shame of needing nappies and panty pads in old age means that a large proportion are sold online, and there is a lot of competition for those lucrative sales. Marketing bloopers have been legendary – in Sweden a diaper maker decided to send a free sample to every man over 55, resulting in thousands of angry men overloading their switchboard. It's a marketing minefield, satirised twice by Saturday Night Live.

But doing wees and poos involuntarily is just the tip of the small iceberg of medical embarrassments and failures we can expect once we pass 65, there are so many ailments we're more prone to. Nappies and panty pads are a fairly low-tech answer to a wee problem; most of the issues we face have much more high-tech solutions.

Most of us hitting 65 now expect to be active for another decade or three – we expect our doctors and surgeons and physiotherapists to provide the necessary joint replacements, life-saving operations, medication, exercise regimes and technology to keep us running, hiking, skiing, playing tennis, swimming and surfing for as long as these advancements allow. It's a long way from being sent out on an ice floe when you're nearing the end of your days.

Waiting times have blown out for joint replacements in public hospitals, and a large number of people have been rejected from the waiting list as a result. Somehow we have to find a way to afford it, because the struggling health budget simply can't fork out for so many operations. Between 2005 and 2015, hip operations trebled in number, and there were six times as many knee operations, thanks to the booming number of people hitting old age. New Zealand medicos started a Joint Register in 1999 and already there are 165,000 new synthetic joints listed on it.

Arthritis is the most common ailment for the over 65s; the thinning, more fragile bones of osteoporosis are also comparatively common, resulting in more broken bones. Heart disease is our biggest killer of over 65s; cancer the second most common killer. With both diseases, though, medical advancements mean we're much more likely to survive them than we would have 20 or 30 years ago. I'm testament to this, having survived breast cancer for the past 18 years. Respiratory disease is also right up there in popping us off.

About 10 per cent of over 65s are likely to get Alzheimer's, though more of us have mild cognitive impairment, quite believable given the number of times I forget where I put my keys or phone. Apparently the difference with Alzheimer's is not just forgetting where the keys or phone are, but forgetting what they're for.

Losing our balance develops as we get older due to inner ear problems or the medication we're prescribed for other ailments; sleeplessness becomes more common; some get restless leg syndrome; and about a third will get macular degeneration (the part of the eye that sees fine detail breaks down). A smaller proportion get glaucoma.

Then there's the old age spread – sadly a natural progression of middle aged spread. Far too many of us (about 40 per cent) are overweight, and find it harder to shift the kilos as we get older. It's not just that it's harder to exercise when our joints are protesting, or find the willpower to resist that extra glass of wine, it's apparently got something to do with the familiarity the fat has with our bodies – the longer it sticks around, the more it likes being there, lowering our metabolism and resenting our efforts to shake it off. Well, that's my excuse anyway.

It's no surprise, really, that many of the issues we face in old age are a social disaster – incontinence, needing a Zimmer frame, going deaf, fishing out glasses to read the menu, getting fat, losing our mind, and nodding off in the afternoon because we're awake half the night. Some are so embarrassing, no one is ever likely to admit to. Who, for example, is going to admit wearing adult nappies? Or to taking oestrogen when we find we've got something unspeakable like senile vaginitis? An awful lot of post-menopausal women, barely finished sighing with relief to be free of hot flushes and sudden forgetfulness, find the thinning and shrinking tissues result in severely reduced lubrication and, ergo, painful sex. Not that we can talk about it – perish the thought anyone over 65 might mention being sexually active in polite company.

We might be living longer and more agile lives thanks to medical science, but there is no way to escape the ignominy of the many humiliating things that can go wrong as we push 70 and 80, things we have to hide, while we keep up appearances that everything is just the same as when we were young.

Felicity Price ONZM, is an ex-journalist who now writes bestselling chook lit – funny, fast-paced romance-suspense for the over 50s. Read more on felicityprice.com.

Written by Felicity Price. First appeared on Stuff.co.nz.