Some age-related changes, such as wrinkles and grey hair, are
inevitable. It was once thought that changes to muscles, bones and
joints were inevitable too. But researchers now suspect that at least
half of the changes to bones and muscles are because they are simply
not used often enough. Lack of physical activity can set up a vicious
cycle, because an older person who lives a sedentary lifestyle is prone
to a range of diseases that could impose bed rest. It is thought that a
bed-ridden older person can lose around five per cent of their muscle
strength for each day of their time in bed. Someone who is feeling weak
and unsteady on their feet may avoid exercise, and so the physical
decline continues. There is growing evidence that increasing muscle and
bone fitness improves health and reduces the risk of disability and
chronic disease.
Musculoskeletal diseases common in older age Nearly half of all Australians over the age of 75 years have some kind
of disability. Some diseases of the musculoskeletal system are more
common in older people. These include:
Osteoarthritis – the cartilage within the joint breaks down, causing pain and stiffness.
Osteomalacia – the bones become soft, due to problems with the metabolism of vitamin D.
Osteoporosis – the bones lose mass and become brittle. Fractures are more likely.
Rheumatoid arthritis – inflammation of the joints.
Muscle weakness and pain – any of the above conditions can affect the proper functioning of the associated muscles.
Age-related changes in muscle Muscle loses size and strength as we get older. This is caused by a number of factors working in combination, including:
Individual muscle fibres shrink in size.
Muscle fibres reduce in number.
Lost muscle fibres are replaced by non-functioning fibrous tissue.
The energy ‘powerhouse’ within each muscle cell, called the mitochondria, reduces its output.
Enzyme changes within each muscle cell reduce the amount of available energy.
The nerve impulses that control muscle cells aren’t transmitted as efficiently.
Age-related changes in bone Bones start to lose mass during
middle age. This process accelerates after the age of 50 years,
particularly for women. About one in four women over the age of 80
years is at risk of fracturing her hip. Bones become less dense as we
age for a number of reasons, including:
A sedentary lifestyle causes bone atrophy.
The hormonal changes of menopause trigger the loss of minerals in bone tissue.
In men, the gradual decline in sex hormones leads to the later development of osteoporosis.
Loss of muscle tissue is associated with reduced bone mass.
Age-related changes in joints Most of the age-related changes
to joints are caused by lack of exercise. Cartilage doesn’t have a
blood supply, and relies instead on synovial fluid moving in and out of
the joint to nourish it and take away wastes. This requires joint
movement and some joint stress. A sedentary lifestyle causes the
cartilage to shrink and stiffen, reducing joint mobility.
Exercise – physical activity is the key Recent studies show that less than one in 10 Australians over the age
of 50 years does enough exercise to improve or maintain cardiovascular
fitness. Exercise can not only prevent many of the age-related changes
to muscles, bones and joints, but can reverse these changes too. It’s
never too late to start living an active lifestyle. Research shows
that:
Older people can boost their muscle size and strength, just like younger people, through exercise.
Exercise increases the size and number of ‘fast twitch’ muscle
fibres, which improves muscle strength and the speed of muscular
contractions.
Falls are less likely if muscle strength and reaction times are improved.
There is some evidence that older people with osteoporosis can
increase their bone mass through weight bearing physical activity, more
so in women (in the hip and lumber spine) than in men. At this stage
the evidence is more convincing that physical activity maintains bone
mass in the elderly.
Weight bearing exercise, such as walking or weight training,
is the best type of exercise for maintenance of bone mass. There is a
suggestion that twisting or rotational movements where the muscles
attachments pull on the bone are also beneficial.
Older people who exercise in water (which is not weight
bearing) may still experience increases in bone and muscle mass
compared to sedentary older people.
People with arthritis can improve their symptoms through regular exercise.
See your doctor See your doctor before you start any new
physical activity program. If you haven’t exercised for a long time,
are elderly or have a chronic disease (such as arthritis), your doctor,
physiotherapist or exercise physiologist can help tailor an appropriate
and safe exercise program for you. If you suffer from osteoporosis, you
may also be advised to take more calcium. Sometimes, medications are
needed to treat osteoporosis.
Where to get help
Your doctor
Physiotherapist
Exercise physiologist
'Go for your life' Infoline Tel. 1300 739 899
Things to remember
At least half of the age-related changes to muscles, bones and joints are caused by disuse.
Recent studies show that less than one in 10 Australians over
the age of 50 years do enough exercise to improve or maintain
cardiovascular fitness.
See your doctor before starting any new exercise program.
Acknowledgement This information has been sourced from the Better Health Channel in consultation with Kinect Australia (inc VICFIT in Victoria).
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