5
ISSUES: Fitness & Health
Chapter 1: About fitness
Howphysical activity prevents cancer
Being physically active isn’t just good for your heart: there is lots of evidence that it can also
reduce the risk of developing breast, bowel or womb cancer. Keeping active could help to
prevent around 3,400 cases of cancer every year in theUK.
How does physical
activity affect hormone
levels?
Hormones are chemical messages
that get carried around our bodies in
our blood. They help tell our bodies
and cells what to do. Being physically
active can change the levels of some
hormones, including oestrogen and
insulin.
In women, physical activity can lower
the level of oestrogen. Oestrogen is
thought to fuel the development of
many breast and womb cancers, so
reducing the levels of this hormone
could help to reduce the risk.
Activity can also reduce the amount
of insulin in our blood. Insulin is very
important in controlling how our
bodies use and store energy from
food. Changes in insulin levels can
have effects all over the body. And
scientists think insulin can turn on
signals that tell cells to multiply.
Because cancer starts when cells
multiply out of control, lowering
insulin levels could help stop some
types of cancer from developing.
How does physical
activity prevent bowel
cancer?
Physical activity helps food move
through our bowels. When food
moves through our bowels quickly
this reduces the amount of time that
the inside lining of the bowel is in
contact with any harmful chemicals,
like those releasedwhen you consume
alcohol or red and processed meat.
So there’s less chance of them being
able to cause damage that could lead
to cancer.
Being active also helps control
levels of inflammation in the bowel.
Inflammation is a normal part of the
way our bodies react to injury or
infections. But it can sometimes cause
even more damage, particularly when
it keeps happening in the same place.
This can lead to the cells multiplying
much more frequently than usual,
to replace dead and damaged cells,
increasing the chances of mistakes
that could lead to cancer.
Is physical activity just
good for us because of its
effects on weight?
Being physically active, along with a
healthy, balanced diet, can also help
youmanage your weight. And keeping
to a healthy weight is another great
way to reduce the risk of developing
cancer and other diseases.
But physical activity has benefits
above and beyond weight control,
and it doesn’t only reduce the risk of
cancer through its effects on weight.
Howdoes physical activity
benefit cancer patients?
There is also good evidence that being
active can help people during and
following cancer treatment. If you are
a cancer patient and want to be more
active, discuss with your doctor what
would work best for you.
24 March 2015
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The above information is reprinted
with kind permission from Cancer
Research. Please visit www.
cancerresearchuk.org for further
information.
© Cancer Research UK 2017
Breast
after menopause
Bowel
Womb
Being physically inactive could cause
three types of cancer
Larger circles indicate cancers with
more UK cancer cases linked
to being physically inactive
Source: Cancer Research UK
