Stress could leave you at risk of infections by ‘turning off’ the immune system

Tired, stressed businesswoman at laptop with head in hands
"Continuous" release of the "stress hormone" cortisol may "turn off" immunity. [Photo: Getty]

Whether it’s meeting deadlines, juggling the school run or even road rage, we all feel frazzled from time-to-time.

While it may seem harmless, an expert has warned long-term stress could leave you at risk of infections.

The “continuous” release of the “stress hormone” cortisol is thought to “turn off” our ability to fight bacteria and viruses.

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“Cortisol has a powerful effect on the immune system,” Professor Angela Clow, from the University of Westminster, said.

“It inhibits ‘nighttime immunity’, which is when immune cells gobble up bacteria and even ward off cancer progression.”

This differs from daytime immunity, which protects against more immediate risks, she added.

Scientists from Ohio State University first identified a link between stress and immunity when they analysed the healing time of puncture wounds in dementia caregivers.

Looking after someone with dementia forces a carer to contend with “loss of memory, inappropriate emotions, and wandering and restless behaviour of their loved ones”, they wrote.

Compared to “controls”, the caregivers’ wounds took 24% longer to heal, “providing evidence chronic stress can delay repair”.

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How feeling frazzled affects our immune function is muddled and complex.

Cortisol is thought to “turn off” our body’s natural circadian rhythm, which regulates the sleep-wake cycle.

Speaking at the Royal Society of Medicine, Professor Clow said: “Our whole body functions on a 24 hour cycle.

“Cortisol is great at the right time of day. It boosts the brain.”

Studies have shown high cortisol within the first half-an-hour of waking improves cognitive function. If elevated in the evening, however, the opposite is true.

Many of us are in the “resilience phase” of stress. This enables sufferers to revert back to their calm state once the stress source has passed.

Over time, however, we may be left permanently stressed out, which seriously affects our health.

“Your immune system stops ‘knowing what time it is’ so can’t function as well,” Professor Clow said.

How to combat stress

While our lives may feel hectic at times, stress does not have to be inevitable.

“Cortisol is not immovable,” Professor Clow said. “It’s remarkably malleable.”

When it comes to feeling calmer, exercise should be the go-to.

“Of all the interventions, physical activity is the most potent,” Professor Clow said. “Cortisol generates an energy drive and exercises ‘uses it up.”

Studies have also shown listening to music lowers our level of the hormone, while exposure to art after surgery helps hospital patients feel less frazzled.

Whichever way you choose to channel stress, Professor Clow emphasises you must enjoy it.

“You’ve got to do what you like doing,” she said. “There’s no recipe for everybody.”

Confiding in a loved one may also make your problems feel more manageable.

“Maintaining a strong support network in general can help you to identify solutions and change your perspective,” Dr Daniel Atkinson, clinical lead at, told Yahoo UK.

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Both the NHS and Dr Atkinson also recommend mindfulness to help stress sufferers feel more in control.

“Mindfulness is the act of giving more attention to your thoughts and feelings in the present, as well as to the environment around you,” Dr Atkinson said.

“It helps to interrupt the ‘autopilot’ mode that’s very easy to inhabit on a daily basis.

“And the increased awareness that’s given to our thoughts and feelings can better equip us to notice signs of stress developing.”

If “self help” fails to ease your stress, Dr Diana Gall from Doctor4U recommends seeking medical help.

“If you’re wondering whether or not the stress you’re facing is ‘too much stress’, then it’s best to talk to your GP or seek a mental-health expert,” she previously told Yahoo UK.

Warning signs may include struggling at work or school, finding it difficult to get through the day, turning to drugs or alcohol, insomnia, depression and even suicidal thoughts, Dr Gall added.

If you have had thoughts of self harm or suicide, the Samaritans are available 24/7 on 116 123.