When Jen Martin tested positive for COVID-19 in early February, she was surprised by just how unwell she felt.
"I didn't have a fever but I had very serious aches and pains, crazy lethargy, and a hacking cough," she says.
"I certainly felt worse than I had expected to, having heard all of the stories about it being mild."
Six weeks later, the Melbourne-based academic still feels pretty average, dealing with regular headaches, daily fatigue, and disrupted sleep.
"In the early days, the cause [of my sleep problems] was obvious — I couldn't stop coughing," she says.
"But even since I've stopped coughing, I've noticed this very, very interrupted sleep pattern."
Jen says she's able to fall asleep reasonably quickly, but often finds herself awake two hours later.
She struggles to get back to sleep and stay asleep for more than an hour, before abruptly waking again — a cycle that repeats itself throughout the night.
"I try strategies to get back to sleep, knowing that I've got work the next day and I'm feeling really tired … but I just really struggle, it's very frustrating."
Early mornings, which used to be the most productive part of her day, are now noticeably slower, on account of feeling "dozy".
"I feel very grateful that I have a job that I can largely do from home," Jen says.
"But there's just this little voice in the back of my head that's like, 'Jeez, it would be nice to get a solid sleep one of these days'."
Sleep disturbances seen in post-COVID patients
While most people with a mild or moderate case of COVID-19 recover within about two weeks, others experience lingering symptoms, such as fatigue and shortness of breath.
Sleep disturbances are a well-documented symptom of long COVID, which is generally regarded as the persistence (or emergence) of symptoms at least three months after a SARS-CoV-2 infection.
But respiratory and sleep physician Megan Rees says people can also experience sleep problems during the acute phase of a COVID-19 infection and in the weeks and months that follow.
"At least a third to half of our patients say [their sleep] is worse than it was before they got COVID-19," says Dr Rees, who is head of the Royal Melbourne Hospital's Sleep and Respiratory unit.
When it comes to sleep disturbances, Dr Rees says people recently recovering from COVID-19 — and those diagnosed with long COVID — experience "a mixture of problems".
"There seems to be a bit of insomnia, so difficulty being able to sleep at the time that you want, but also feeling tired and wanting to sleep during the daytime," she says.
"In addition to that, there is what we call 'phase delay' or a disruption to your natural circadian rhythm.
"People aren't always finding it easy to be awake at the time they usually like to be awake, and have difficulty being asleep at the time they want to be asleep."
What triggers sleep problems following COVID-19?
The cause is likely to be "multifactorial", Dr Rees says, meaning there's usually several factors involved.
"There's likely to be, to some extent, a direct viral effect — so viruses cause a lot of inflammation in the body, and those inflammatory chemicals as they circulate can disrupt sleep," she says.
"Predominantly, they make you more fatigued or wanting to sleep at different times, but they can also upset your natural rhythms."
Earlier this year, Australian researchers found that people with long COVID — even those whose initial infection was mild — had a sustained inflammatory response for at least eight months after their infection.
Dr Rees says more research is needed to understand the impacts of this ongoing inflammation, but that "it's not surprising that an inflammatory illness like COVID-19 could disrupt sleep".
"Sleep is a really complex process that actually takes a lot of coordination between various aspects of your brain to achieve," she says.
The persistence of physical symptoms, particularly chest pain and breathlessness — "two of the most common symptoms seen in people as they recover" — can also cause disruptions to sleep.
"Those symptoms can be quite frightening and people can be concerned that something more serious, like a heart attack, is occurring," she says.
Even for people whose physical symptoms have resolved, they may still feel afraid to fall asleep weeks or months later, worried they will struggle to breath.
In addition to the illness itself, Dr Rees says changes to regular routines during the isolation and recovery periods can also put people's sleep routines out of whack.
"Often you do have a disruption to your normal rhythms of life, so people might be sleeping in, watching screens a little more in the evenings, or having afternoon naps," she says.
"They might also not be able to do as many of their usual activities that help them have a normal sleep cycle so that they're alert in the mornings and tired in the evenings.
"That natural cycle, where we follow the sun rising and the sun setting, is often a bit disrupted."
Anxiety and ongoing stress a key factor
According to respiratory physician Anthony Byrne, the anxiety that's often triggered when people become unwell may also play a part in disturbing sleep.
"Being unwell with a severe virus, whether or not you're in hospital, would cause most people to have some level of anxiety about their own health and how they're going to go in the short term as well as in the long term," says Dr Byrne, who treats both acute and long COVID patients at St Vincent's Hospital in Sydney.
Dr Byrne says research suggests people who had been infected with COVID-19 experienced increased levels of anxiety, and that there is a clear link between anxiety and poor sleep.
"The circadian rhythm is a natural rhythm inbuilt in us that means we have a certain amount of circulating melatonin and other factors in the blood that allow us to sleep at night," he says.
"When you have anxiety and other neurotransmitters that are overactive in the brain, you get an inability to relax … you're sort of in a fight/flight response, and so it's hard to settle down.
"Then you can have this delayed sleep onset or difficulty getting to sleep … and that's one of the things that has been found in patients post-COVID."
Anxiety is also closely linked with insomnia, which can sometimes begin during times of increased stress, and continue even once the stress has gone away.
Dr Byrne says the psychological impacts of a severe COVID infection can sometimes be seen months after infection.
"One example is a young healthy guy that developed long COVID symptoms after he was admitted to hospital with COVID pneumonia," Dr Byrne says.
"One reason that he was waking up at night was because he was getting flashbacks to when he was really breathless and on oxygen at the hospital.
"Even though he recovered from that, it was almost like post-traumatic stress."
COVID-19 may expose existing sleep problems
While Dr Bryne acknowledges that sleep disturbances post-COVID are "a big, important problem", he says it's important to note that some sleep issues may have existed prior to infection.
"Obstructive sleep apnoea, for example, is a risk factor for severe COVID and is often undiagnosed [prior to COVID infection]," he says.
"It's a very well-researched disorder that affects sleep quality and the ability to feel refreshed.
"So you can get this overlap of disorders, which are not causing long COVID, but they're there, and they're potentially modifiable and treatable."
When investigating the cause of sleep problems following COVID-19, Dr Byrne says it's important to do a comprehensive assessment of existing health problems and sleep habits before "laying blame solely on the shoulders of COVID".
"When you go to see a GP or sleep physician, one of the first things that will be asked is: what's your sleep routine?" he says.
"How's your sleep hygiene? Are you going to bed at a reasonable hour? Are you avoiding caffeine and cutting out all the usual things?
A lot of people are also already experiencing heightened anxiety because of the pandemic, which may well be exacerbated if they get infected and become unwell, he adds.
"If you’ve got a background anxiety disorder and then you’ve got COVID on top of that, it's going to make things worse — including sleep problems."
Do these COVID-related sleep problems usually go away?
The good news, according to Dr Rees, is that most post and long COVID patients, in her experience, improve with time.
"We certainly understand a lot more about [persistent symptoms] now, and we are seeing a slow, steady recovery for the vast majority of people," she says.
For those in the community struggling with sleep problems following a COVID infection, Dr Rees says there are a few things worth trying to improve sleep quality.
"I guess the first thing to say is that you're not crazy: you've had a serious infection and this unfortunately can be a part of that illness, but it should get better over time," she says.
The first thing she recommends to improve sleep is to ensure you follow a regular sleep-wake cycle.
"I recommend light exercise outside in the mornings, ideally walking without sunglasses," Dr Rees says.
"Then towards the end of the day, have some relaxing, wind-down time in the evening, ideally without screens."
In addition to avoiding the blue light that's emitted from electronic devices, she recommends limiting alcohol intake and cigarettes.
"Although you will doze off more easily if you have a few drinks, alcohol prevents you from going into those deeper, restorative phases of sleep."
Dr Bryne adds that melatonin tablets, over-the-counter or via prescription, may also help to alleviate sleep issues.
Finally, Dr Rees says if people haven't yet received their COVID-19 booster vaccine, persistent COVID symptoms weren't a reason to delay it.
"People were a little worried that getting vaccinated might worsen their long COVID symptoms, but actually the reverse is true," she says.
"We've found that people who've already been suffering from long COVID can have their symptoms reduced if they get a booster dose."
