People are often surprised by how fatigued they are during a Covid infection.

Fatigue is more than being worn out or sleepy. It's an excessive tiredness that persists despite resting or good sleep. It's likely a result of our body's strong immune response to the virus.

But in some people the fatigue drags on even when the infection is gone. This can be debilitating and frustrating. Simply resting more makes no difference.

Here's what we know about post-Covid fatigue, and what can help.

Fatigue or tiredness? What's the difference?

The term fatigue can mean different things to different people. Some people mean their muscles are easily weakened.

Walking to the mailbox feels like they have run a marathon.

Others describe a generalised exhaustion, whether they are moving or not. People can experience physical, mental or emotional fatigue, or any combination of these.

The difference between tiredness and fatigue is this: tiredness can get better with enough rest, while fatigue persists even if someone is sleeping and resting more than ever.

How big a problem is this?

Because there is no agreed definition of post-Covid fatigue, it is impossible to give exact numbers of how many people experience it.

Estimates vary considerably worldwide.

One review of 21 studies found 13-33% of people were fatigued 16-20 weeks after their symptoms started. This is a worryingly widespread problem.

When should I see my GP?

There are many potential causes of fatigue. Even before the pandemic, fatigue was one of the most common reasons to see a GP.

Most serious causes can be ruled out when your GP asks about your symptoms and examines you.

Sometimes your GP will investigate further, perhaps by ordering blood tests.

Symptoms that should raise particular concern include fevers, unexplained weight loss, unusual bleeding or bruising, pain (anywhere) that wakes you from sleep, or drenching night sweats.

If your fatigue is getting worse rather than better, or you cannot care for yourself properly, you really should seek medical care.

Is it like long COVID?

Early in the pandemic, we realised some patients had a cluster of debilitating symptoms that dragged on for months, which we now call long Covid.

Some 85% of long Covid patients experience fatigue, making it one of the most common long Covid symptoms.

However, people with long Covid have a range of other symptoms, such as brain fog , headaches and muscle aches.

Patients with long Covid therefore experience more than fatigue, and sometimes don't have fatigue at all.

Is this like chronic fatigue syndrome?

We knew about chronic fatigue syndrome, otherwise known as myalgic encephalomyelitis, well before Covid.

This often develops after a viral infection (for instance after infection with Epstein-Barr virus). So, understandably, there has been concern around the coronavirus potentially triggering chronic fatigue syndrome.

There are striking similarities between chronic fatigue syndrome and long Covid. Both involve debilitating fatigue, brain fog and/or muscle aches.

But at this stage, researchers are still untangling any link between post-COVID fatigue, long COVID and chronic fatigue syndrome.

For now, we know many people will have post-COVID fatigue but thankfully do not go on to develop long COVID or chronic fatigue syndrome.

What helps me manage my fatigue?

Expect you or a loved one may develop post-COVID fatigue, regardless of how unwell you or they were during the actual infection.

Vaccines help reduce the risk of post-COVID fatigue by lowering the chance of catching COVID in the first place. Vaccinated people who do catch COVID are less likely to report fatigue and are less likely to develop long COVID.

However, vaccination is not 100% protective and there are plenty of fully vaccinated people who go on to develop longer term fatigue.

The evidence for what helps you recover from post-COVID fatigue is in its infancy. However, a few things do help:

1. pace yourself: adjust the return to normal activities to your energy levels. Choose your priorities and focus on what you can do rather than what you can't.

2. return to exercise gradually: a gradual return to exercise may help your recovery, but you may need some support about how to manage or avoid fatigue afterwards. Some therapists occupational therapists, physiotherapists and exercise physiologists specialise in this. So ask your GP for a recommendation.

3. prioritise sleep: rather than feeling guilty about sleeping so much, remind yourself that while you sleep, your body conserves energy and heals. Disrupted sleep patterns are an unfortunate COVID symptom. Having a strict bedtime, while also resting when you feel tired during the day, is important.

4. eat a range of nutritious foods: loss of smell, taste and appetite from COVID can make this tricky. However, try to view food as a way of fuelling your body with both energy and the micronutrients it needs to heal. Be careful not to spend a fortune on unproven remedies that often look good in small studies, but more robust research finds make little difference.

5. monitor your fatigue: keep a diary to monitor your fatigue, and look for a gradual improvement. You will have good days and bad days, but overall there should be a slow trajectory towards recovery. If you are going backwards, get input from a health professional, such as your GP.