When I'm ill, should I just let my fever burn itself out? © Getty

When I’m ill, should I just let my fever burn itself out?

It’s getting hot in here so put on all your clothes… Fevers make your body a hostile environment for viruses and can mostly help with recovery.

Asked by: Benjamin Matthews, Crewe

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Fever is a classic sign of a viral infection like the flu. There’s nothing for it but to rest, drink plenty of water and take paracetamol to deal with the aches and high temperature. At least, that’s the standard advice, but there’s growing evidence that it might actually hinder recovery.

That’s because the fever isn’t caused by the virus itself, but by the body’s own infection-fighting system. First recognised by physicians over 2,000 years ago, the benefits of having a fever (a temperature of at least 38°C) have been confirmed by the latest immune system research. This has shown that viruses struggle to thrive at high temperatures, while our immune system works better.

A host of other organisms from mammals and birds to amphibians and reptiles have also evolved immune systems that increase body temperature to fight infection. So while lowering our temperature might make us feel more comfortable, it could do more harm than good.

So why doesn’t the standard advice reflect this? Part of the reason is the principle that the body must stay within a strict temperature range to be healthy. So if the body struggles to do this, the argument runs, it must be given help. Yet there’s been little research into whether fever-busting drugs like paracetamol really do help patients, and among the studies that have been carried out, some have found hints that it can make them worse.

Another reason fevers are seen as bad is concern that they can run out of control. With some conditions, like heatstroke and some kinds of brain damage, that’s a proven risk. Even so, for conditions like flu, the standard advice is starting to look questionable.

This said, the story is still not complete, so in the meantime, if you have a fever, we recommend following the current NHS guidelines of treating it with medication.

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