Symptoms of flu 

The symptoms of flu usually develop within one to three days of becoming infected. Most people will feel better within a week.

However, you may have a lingering cough and still feel very tired for a further couple of weeks.

Main symptoms

Flu can give you any of the following symptoms:

Is it flu or a cold?

It can sometimes be difficult to tell if you have flu or just a cold, as the symptoms can be quite similar. The main differences are:

Flu symptoms:

  • come on quickly
  • usually include fever and aching muscles
  • make you feel too unwell to continue your usual activities

Cold symptoms:

  • come on gradually
  • mainly affect your nose and throat
  • are fairly mild, so you can still get around and are usually well enough to go to work

When to visit your GP

If you are otherwise fit and healthy, there's usually no need to visit your GP if you have flu-like symptoms.

You should just rest at home until you feel better, while keeping warm, drinking plenty of water and taking painkillers if necessary. Read more about how to treat flu.

Consider visiting your GP if:

  • you're 65 years of age or over
  • you're pregnant
  • you have a long-term medical condition – such as diabetes, heart disease, lung disease, kidney disease or a neurological disease
  • you have a weakened immune system – for example, because you're having chemotherapy or have HIV
  • you develop chest pain, shortness of breath or difficulty breathing, or start coughing up blood
  • your symptoms are getting worse over time or haven't improved after a week

In these situations, you may need extra treatment to prevent or treat complications of flu.

Page last reviewed: 01/04/2015

Next review due: 01/04/2017