Why being stressed can wreak havoc with your immune system and make you physically illTests showed the immune systems of those who were stressed were less sensitive to cortisol
00:35 GMT, 3 April 2012
As many of us know, stress can leave you feeling run down. Now scientists think they can explain why.
A study has shown how long-term stress plays havoc with the immune system, raising the odds of catching a cold.
The same process could also explain the role of traumatic events in raising the odds of illnesses from heart disease to depression.
Feeling the pressure: The study showed that those living stressful lives were more likely to become sick (Posed by model)
Scientists in the U.S. questioned 176 men and women about difficult experiences they had been through in the past 12 months.
Drops of the common cold virus were
then dripped into their nose and scientists checked if they caught the
germ. Those who had been under stress were twice as likely to develop a
Importantly, tests showed their immune
systems had become less sensitive to cortisol, a stress hormone which
dampens the immune system.
This allowed a part of the immune
reaction called the inflammatory response to grow, leading to the
symptoms of the cold, the journal Proceedings of the National Academy of
A second experiment confirmed that the inflammatory response feeds off stress.
which can show itself as redness, itchiness, swelling and pain, occurs
when the immune system spots an infection and is a vital first step in
fending off disease.
Common cold: Viruses are easier to pick up if your immune system is compromised (Posed by model)
However, when it persists, it not only raises the risk of colds but many other illnesses.
Professor Sheldon Cohen, of Carnegie Mellon University in Pennsylvania,
said: ‘The immune system’s ability to regulate inflammation predicts
who will develop a cold, but more importantly it provides an explanation
of how stress can promote disease.
‘When under stress, cells of the immune system are unable to respond to hormonal control, and consequently, produce levels of inflammation that promote disease.
‘Because inflammation plays a role in many diseases such as cardiovascular, asthma and autoimmune disorders, this model suggests why stress impacts them as well.
‘Knowing this is important for identifying which diseases may be influenced by stress and for preventing disease in chronically stressed people.’
There are also many other ways that stress can make us ill.
For instance, researchers at the London School of Economics have warned that a growing reliance on fat and salt-laden fast food and time-saving technology, coupled with long working hours, is sending blood pressure soaring.
One third of British adults already suffer from the condition which doubles the risk of dying from heart attack or stroke.
Research has also linked stress, anxiety and low self-esteem in pregnant women with an increased risk of stillbirth and with stunting a child’s intelligence.
Children from stressed pregnancies are also more likely to be hyperactive, have emotional problems and not do as they are told as well as suffering from stress themselves.