What you need to know about post-viral fatigue

While COVID-19 is a short-lived illness in most people, others experience lingering symptoms, including fatigue, for months after their initial infection. So what should you do if you're suffering with post-viral fatigue, following COVID-19 or a different virus?

By now, many of us are familiar with the idea of 'long COVID' - a lingering post-viral illness that can follow a COVID-19 infection. Most people who contract the coronavirus recover within two to three weeks. However, we now know there's a subset of patients for whom that's not the case.

The British Medical Journal defines 'long COVID' as "illness in people who have either recovered from COVID-19 but are still reporting lasting effects of the infection or have had the usual symptoms for far longer than would be expected". While we don't know exactly how many people this applies to, the tally could be as high as one in 10 of those infected.

According to data from the UK's COVID-19 symptom app, there are around 300,000 people in the UK who have reported symptoms lasting for more than a month. Over 60,000 (1.5% of those taking part in the study) were still experiencing symptoms after three months.

What is post-viral fatigue?

While many of these 'long haulers' only suffer mildly, others experience a debilitating array of symptoms including breathlessness, muscle pain and a persistent cough. One of the most prevalent long-term symptoms is excessive fatigue or exhaustion.

"Post-viral fatigue is characterised by a general feeling of being unwell as well as extreme tiredness and has been noted in patients recovering from other viruses, such as the flu or mumps," explains Dr Michael Beckles, consultant respiratory physician at HCA Healthcare UK. "Other symptoms that may be present include concentration loss, sore throat, headaches, swollen lymph nodes and unexplained muscle and joint pain."

Unfortunately, anybody can be affected by the long-term effects of the coronavirus - whether or not their initial infection was severe.

"Typically, the older generation, or those who already have a pre-existing medical condition are more likely to experience post-viral fatigue. However, there have been reports of younger, healthy people also suffering from the condition," says Beckles.

What causes it?

In some cases, the fatigue can resemble chronic fatigue syndrome (CFS)/myalgic encephalomyelitis (ME) - a chronic illness in which the fatigue limits a person's ability to carry out ordinary daily activities. Sleep is non-restorative (you don't wake feeling at all refreshed), and the tiredness can intensify after very minor mental or physical exertion.

"The trigger for post-viral fatigue seems to be a reaction to the virus itself. Some doctors may treat this extreme tiredness in a similar way to CFS/ME," says Beckles. "However, while the factors that cause a patient to have ME are often impossible to identify, post-viral fatigue always manifests after suffering from a virus. Certain viruses, such as coronavirus, rubella and HIV, are more likely to cause post-viral fatigue than others."

We don't fully understand why post-viral fatigue might occur. However, it may have something to do with the body's immune response to the initial infection. When you are fighting off a virus, the immune system releases chemicals called cytokines, which promote inflammation and cause many of the classic symptoms of viral infection (eg, tiredness, aches and pains, malaise).

This is part of its frontline attack on the invading virus, and normally it stops once the virus itself has been dealt with. But recent studies suggest that in some cases, levels of cytokines fail to return to normal, causing ongoing symptoms.

"Other reasons for post-viral fatigue may include inflammation of the nervous tissues, or an individual's own unusual response to the virus which has remained dormant within their body for some time," says Beckles.

How to alleviate symptoms

So what should you do if you're suffering from post-viral fatigue? Beckles says that while there are no precise treatments, there are many things you can do to ease your symptoms and aid your recovery.

"Taking over-the-counter pain relief such as paracetamol may help ease any lingering pain. By managing pain, you may also be able to improve the quantity and quality of your sleep at night, thereby reducing fatigue throughout the day," he says. "Going to bed at the same time each night and setting your alarm for the same time each morning will help your body slowly ease into a sleeping schedule."

He warns that, while resting throughout the day is important, too much rest can actually cause sufferers to feel more fatigued. It's sensible to take small, frequent naps during the day, if you feel exhausted, rather than sleeping for several hours at a time.

"Doing some gentle exercise like walking or swimming or relaxation techniques such as yoga can also help to reduce tiredness and stop the muscles from shrinking due to a lack of movement," he says. However, it is important to take things very gently - as we've heard, in some people even minor physical exertion can cause rebound worsening of fatigue.

What to do if you're worried

Recovery from post-viral fatigue can vary a lot from one person to the next. Some people are back to normal within a month or two, while others experience lingering symptoms for years. However, there is some evidence to suggest that getting an early diagnosis may improve recovery.

If you're concerned you may be suffering with 'long COVID', or that you've developed an illness similar to CFS/ME, it's important to speak with your doctor as soon as possible. They can investigate further and, if necessary, refer you to specialist services. The NHS has recently set up the Your COVID Recovery programme, but while there is extensive advice on their website, there are as yet few clinics where tailored treatment can be offered. In addition, some patient groups have criticised the site for setting unrealistic targets for exercise and activity.

"If your symptoms of fatigue, or any other long-term symptom of COVID, are extreme, difficult to manage or causing you distress, you should seek support from a medical specialist - such as my own team at The Wellington Hospital Post COVID Rehab," says Beckles. "There are several treatment and rehabilitation centres which have been set up across the UK to help those suffering from the long-term effects of COVID-19, so I'd recommend looking into the different forms of rehabilitation and working out with your doctor what would be best for you."

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