BRAIN
- Starts aging at 20
As we get older, the number of nerve cells - or neurons - in the brain decrease.
We start with around 100 billion, but in our 20s this number starts to decline.
By 40, we could be losing up to 10,000 per day, affecting memory, co-ordination
and brain function.
GUT
- Starts aging at 55.
A healthy gut has a good balance between harmful and 'friendly' bacteria. But
levels of friendly bacteria in the gut drop significantly after 55, particularly
in the large intestine, says Tom MacDonald, professor of immunology at Barts And
The London medical school. As a result, we suffer from poor digestion and an
increased risk of gut disease. Constipatio n is more likely as we age, as the
flow of digestive juices from the stomach, liver, pancreas and small intestine
slows down.
BREASTS
- Start aging at 35
BY their mid-30s, woman's breasts start losing tissue and fat, reducing size and
fullness. Sagging starts properly at 40 and the aureole (the area surrounding
the nipple) can shrink considerably.
BLADDER
- Starts aging at 65
Loss of bladder control is more likely when you hit 65. Women are more
vulnerable to bladder problems as, after the menopause, declining estrogen
levels make tissues in the urethra - the tube through which urine passes -
thinner and weaker, reducing bladder support. Bladder capacity in an older adult
generally is about half that of a younger person - about two cups in a
30-year-old and one cup in a 70-year-old. ...
LUNGS
- Start aging at 20
Lung capacity slowly starts to decrease from the age of 20. By the age of 40,
some people are already experiencing breathlessness. This is partly because the
muscles and the rib cage which control breathing stiffen up.
VOICE
- Starts aging at 65
Our voices become quieter and hoarser with age. The soft tissues in the voice
box (larynx) weaken, affecting the pitch, loudness and quality of the voice. A
woman's voice may become huskier and lower in pitch, whereas a man's might
become thinner and higher.
EYES
- Start aging at 40
Glasses are the norm for many over-40s as failing eyesight kicks in - usually
long-sightedness, affecting our ability to see objects up close.
HEART
- Starts aging at 40
The heart pumps blood less effectively around the body as we get older. This is
because blood vessels become less elastic, while arteries can harden or become
blocked because of fatty deposits forming on the coronary arteries - caused by
eating too much saturated fat. The blood supply to the heart is then reduced,
resulting in painful angina. Men over 45 and women over 55 are at greater risk
of a heart attack.
LIVER
- Starts aging at 70
This is the only organ in the body which seems to defy the aging process.
KIDNEYS
- Starts aging at 50
With kidneys, the number of filtering units (nephrons) that remove waste from
the bloodstream starts to reduce in middle age.
PROSTATE
- Starts aging at 50
The prostate often becomes enlarged with age, leading to problems such as
increased need to urinate, says Professor Roger Kirby, director of the Prostate
Centre in London . This is known as benign prostatic hyperplasia and affects
half of men over 50, but rarely those under 40. It occurs when the prostate
absorbs large amounts of the male sex hormone testosterone, which increases the
growth of cells in the prostate. A normal prostate is the size of a walnut, but
the condition can increase this to the size of a tangerine.
BONES
- Start aging at 35
'Throughout our life, old bone is broken down by cells called osteoclasts and
replaced by bone-building cells called osteoblasts - a process called bone
turnover,' explains Robert Moots, professor of rheumatology at Aintree
University Hospital in Liverpool . Children's bone growth is rapid - the
skeleton takes just two years to renew
itself completely. In adults, this can take ten years. Until our mid-20s, bone
density is still increasing. But at 35 bone loss begins as part of the natural
ageing process.
TEETH
- Start aging at 40
As we age, we produce less saliva, which washes away bacteria, so teeth and gums
are more vulnerable to decay. Receding gums - when tissue is lost from gums
around the teeth - is common in adults over 40.
MUSCLES
- Start aging at 30
Muscle is constantly being built up and broken down, a process which is well
balanced in young adults. However, by the time we're 30, breakdown is greater
than buildup, explains Professor Robert Moots. Once adults reach 40, they start
to lose between 0.5 and 2 per cent of their muscle each year. Regular exercise
can help prevent this.
HEARING
- Starts aging mid-50s
More than half of people over 60 lose hearing because of their age, according to
the Royal National Institute for the Deaf.
SKIN
- Starts aging mid-20s
The skin starts to age naturally in your mid-20s.
TASTE AND SMELL
- Start aging at 60
We start out in life with about 10,000 taste buds scattered on the tongue. This
number can halve later in life. After we turn 60, taste and smell gradually
decline, partly as a result of the normal ageing process.
FERTILITY
- Starts aging at 35
Female fertility begins to decline after 35, as the number and quality of eggs
in the ovaries start to fall. The lining of the womb may become thinner, making
it less likely for a fertilised egg to take, and also creating an environment
hostile to sperm.
HAIR
- Starts aging at 30
Male hair loss usually begins in the 30s. Hair is made in tiny pouches just
under the skin's surface, known as follices. A hair normally grows from each
follicle for about three years, is then shed, and a new hair grows. Most people
will have some grey hair by the age of 35. When we are young, our hair is
coloured by the pigments produced by cells in the hair follicle known as
melanocytes.