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What is the flu?

Flu, or influenza, is a virus that many of us will have experienced at one time or another. It’s extremely contagious and very common.

It is often confused with a cold, but flu symptoms are much worse. A cold can bring nothing more than a bout of the sniffles, whereas flu is likely to leave you feeling so poorly that you struggle to get out of bed.

Symptoms of the flu appear quickly, and usually last around a week. You can catch it all year round, although it is more common in the winter months and it is spread by people coughing and sneezing, passing the virus on.

What are the symptoms of flu?

The symptoms of flu include:

  • a temperature of 38°C or higher
  • chills
  • sore throat
  • achy muscles, often in your arms, legs, neck, back and shoulders
  • tiredness
  • cough
  • blocked nose, or a runny nose
  • sneezing
  • headache
  • no appetite
  • wheezing when you breathe
The symptoms will usually clear up within a week or so on their own, but there are cases when you should see a GP. Find out more about flu symptoms and when to see a GP.

What causes the flu?

The flu is caused by a virus, which is spread when someone coughs up or sneezes out tiny droplets that contain it.

The germs can live on your hands and other surfaces for 24 hours, which is what makes it so contagious.

Find out more about the causes and ways to prevent catching the flu.

How is the flu diagnosed?

For most people, the flu won’t need a diagnosis or medical treatment, as it’ll clear up on its own, usually within a week.

However, some people are at higher risks of complications from the flu. If this is the case, you may need treatment for a doctor.

You should speak to a doctor if you have flu and you are pregnant, over the age of 65 or if your symptoms don’t get better after a week. If you have a chronic condition, such as diabetes or asthma, or a weakened immune system, you should also see a GP.

If your baby or child is showing severe flu symptoms, or if you’re worried about them, you should see a GP for more advice.

Find out more about getting a diagnosis for flu.

How is flu treated?

Antibiotics will not work against the flu, as it is a viral infection. If you are fit and healthy then you will usually just need to rest at home until you recover.

You should see a doctor if you have symptoms that do not get better after a week or you are at risk of complications due to the flu.

Find out more about ways you can treat the flu at home and when you should see a GP.

How does the flu affect pregnancy?

n most cases, you’ll recover from the flu quickly and won’t need medical intervention, but sometimes it can cause complications during pregnancy, and it is important to look out for signs of these.

If you’re pregnant and catch the flu, it’s good to see a GP for more advice. Find out more about catching flu during pregnancy here.

Should you exercise when you have the flu?

If your cold turns to a fever, additional exercise is likely to place more stress on your body. It is therefore advisable to wait a few days until you are feeling better before you begin regular exercise again. On return to regular exercise, gradually build yourself back up to your regular training programme.

It is not the best idea to jump back into high intensity training straight away, particularly if you have had a few days off. If it is strength training, start by lifting lighter weights for fewer sets and reps. If it is running, try a few shorter, slower runs before you go for your longer, more difficult efforts. Approaching your return to exercise like this will also help to reduce the risk of injury.

Important considerations when exercising with the flu:

  • Ensure you take the time to recover from physical activity, particularly after performing high intensity or vigorous training

  • Recovery from activity can be slower than usual

  • Be careful about working out when you have a cold and are beginning to feel worse

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