As we get older, we get shorter. But what many people won’t realise is that height is just one thing that shrinks with age: our hearts, facial bones and sex organs all shrink, too.
Such changes often go hand in hand with health problems.
Last week, a U.S. study found the more height you lose, the greater your risk of suffering a fractured hip – and one in three people who suffer a hip fracture die within a year.
Here, LOUISE ATKINSON investigates age-related shrinkages – and how you can protect your body.
Most of us lose at least one-third of an inch (1 cm) in height every decade after the age of 40. By 80, most men will be 2 in (5 cm) shorter than they were in their prime, and women as much as 3.15 in (8 cm) shorter.
Women shrink more than men because levels of the female hormone oestrogen – which helps protect bone health in men and women – fall rapidly at the menopause. Men also tend to have more muscle, which supports their frame.
But even after the age of 35, our bones begin to lose minerals, primarily calcium. As the body’s ability to replace new bone tissue slows, the bones shrink slightly and become brittle, making them more likely to collapse and break – a condition known as osteoporosis.
As well as the bones shrinking, height loss is also caused by the flattening of the discs that sit between the bones of the spine.
The 23 jelly-like discs, which act as the spine’s shock absorbers, are made up of around 88 per cent water. It is normal for them to become compressed during the day as we stand and move around, which squeezes out the fluid.
Then at night, when we lay down, the discs reabsorb fluid and plump up again – which explains why we shrink by as much as half an inch during the course of a day, only to regain the height overnight.
But as we get older, the discs flatten slightly, permanently reducing our height.
Height loss at any age can be a warning sign of osteoporosis, particularly in women, but in men it also appears to be a marker for heart disease.
A large study of British men published in 2006 found that those who lost 1.2 in (2.8 cm) or more over a 20-year period were 46 per cent more likely to have suffered from coronary heart disease.
This, say researchers, is because the common diseases of ageing, including heart disease and osteoporosis, tend to strike together.
HOW TO PROTECT YOURSELF: Around a fifth of us successfully avoid height shrinkage as we age. While good genes help, a healthy lifestyle is key.
To help stave off osteoporosis, you should stick to a healthy diet with adequate calcium (from dairy products and green leafy vegetables, or take 700 mcg of calcium supplements a day) and vitamin D (from sunlight or supplements, 10 mcg daily).
‘Smoking, alcohol and excess caffeine (more than eight cups of coffee or tea a day) can affect bone health, too,’ says Claire Bowring, medical policy officer at the National Osteoporosis Society.
Israeli researchers found that people who engaged in moderately vigorous aerobic activity lost only about half as much height as those who stopped exercising in middle age or never exercised at all.
And if you don’t work to keep muscles strong, particularly the abdominal muscles, you can quickly slip into an unhealthy, slumped S-shape with a projecting tummy and a forward-sloping neck that can knock inches off your height.
Maintaining good posture will also protect ageing discs.
Heart muscle shrinks by an average 0.3 g per year from middle age, affecting its ability to pump blood through your body.
Using MRI scans of men and women aged 45 to 85, researchers at Johns Hopkins University in the U.S. found that with every year it takes longer for the heart muscles to squeeze and relax, by around 2 to 5 per cent, while the actual amount of blood pumped out of the heart falls by 9 millilitres a year.
This, in turn, can cause blood pressure to rise. High blood pressure can cause the heart muscles to thicken as they struggle to pump against increasing resistance.
‘A heart enlarged through hypertension will have a poor blood supply and may become fibrotic and prone to failure,’ says Graham Jackson, consultant cardiologist at Guy’s and St Thomas’ Hospital, London.
HOW TO PROTECT YOURSELF: Like all muscles, the heart becomes stronger and less likely to shrink if it is exercised.
‘Dynamic or aerobic activities that benefit the heart include walking, climbing stairs, gardening, vigorous housework, dancing or using home or gym exercise equipment,’ says Mr Jackson.
‘You don’t have to be Paula Radcliffe – just a good 40-minute walk five times a week is enough to make a difference.’
The male and female sexual organs shrink with age. With men this occurs for two reasons.
First, fatty substances (plaques) are deposited inside tiny arteries in the penis, restricting blood flow (just as they impair blood flow to the heart).
This poor circulation leads to ‘atrophy’ of the tissue within the penis – muscle starts to waste away, leading to loss of length and thickness.
Second, there is a gradual build-up of relatively inelastic collagen (scar tissue) within the stretchy, fibrous sheath that makes erections possible.
‘If a man’s erect penis is 6 in long when he is in his 30s, it might be 5 in or 5½ in when he reaches his 60s or 70s,’ says Dr Irwin Goldstein, director of sexual medicine at Alvarado Hospital in San Diego.
‘Starting around the age of 40, the testicles also begin to shrink’ – by up to a centimetre in diameter between the ages of 30 and 60.
In women, changes are related to reduced levels of oestrogen with the menopause, which reduces blood flow to the area. The uterus also shrinks, returning to the size of that of a pre-adolescent girl, as the body registers that the organ is no longer active and so spares vital resources that other, still active organs can use.
Dwindling oestrogen levels mean mammary glands and milk-producing tissue wither, to be replaced by fat, so the breasts lose their bulk. Natural wear-and-tear on the supporting skin and ligaments makes them more likely to drop.
HOW TO PROTECT YOURSELF: For men, a healthy, low-fat diet that is good for your heart will also be good for your sex life – as healthy arteries all over your body mean better blood flow to the penis.
Women can do little about breast changes (apart from wear a well-fitting bra), but Mr Jackson says that for both men and women, regular sex can slow the shrinking process.
‘It really is a case of use it or lose it,’ he says. ‘If you have regular sex, you improve blood flow and oxygen supply to the sexual organs, and they are much less likely to shrink.’