Different parts of our body age at diferent times

We all accept that getting older is inevitable, and now leading
clinicians have revealed the exact age when different body parts
start to decline, most alarming being the brain and lungs.

French doctors have found that the quality of men's' sperm starts to
deteriorate by 35, so that by the time a man is 45 a third of pregnancies
end in miscarriage. Here, with the help of leading clinicians,
Angela Epstein tells the Daily Mail the ages when different parts of
the body start to lose their battle with time.

BRAIN - Starts ageing 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 ageing 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. Constipation
is more likely as we age, as the flow of digestive juices from the stomach,
liver, pancreas and small intestine slows down.

 

BREASTS - Start ageing at 35
By their mid-30s, women's breasts start losing tissue and fat, reducing
size and fullness. Sagging starts properly at 40 and the areola (the area
surrounding the nipple) can shrink considerably.

 

BLADDER - Starts ageing 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
oestrogen 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 ageing 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 ageing 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 ageing 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 ageing 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 ageing at 70
This is the only organ in the body which seems to defy the aging
process.

 

KIDNEYS - Starts ageing at 50
With kidneys, the number of filtering units (nephrons) that remove waste
from the bloodstream starts to reduce in middle age.

 

PROSTATE - Starts ageing 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 ageing 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 ageing 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 ageing 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 ageing 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 ageing mid-20s
The skin starts to age naturally in your mid-20s.

 

TASTE AND SMELL - Start ageing 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 ageing 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 ageing 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.