It's been seven months since Patrick Hobart contracted COVID-19 and he still remembers being scared he would die in his sleep.
Hobart had the sensation of not being able to get enough air, especially at night, so he stayed up — afraid he'd stop breathing if he let himself doze off.
He was seriously ill for 10 days in March, complete with a high fever and other coronavirus warning signs, but was never hospitalized.
Hobart's symptoms eventually went away, but the night can still come with terrors.
"Even to this day, I still have some anxiety about sleeping," Hobart, a 41-year-old web developer who lives in Fairfield, Connecticut, told TODAY.
"While I'm lying down, I get this involuntary gasp for air… all of a sudden, it's like my body shoves air down my throat."
He's not alone. Half of patients recovering from COVID-19 reported difficulty sleeping as one of the lingering symptoms in a survey of more than 1,500 people in the Survivor Corp Facebook group (a resource for COVID-19 survivors with over 100,000 members). About 16% reported sleeping more than normal. Members of the group are sometimes called "long-haulers" because they discuss long-term effects of the disease.
Dr. Meir Kryger, a sleep researcher and professor at the Yale School of Medicine in New Haven, Connecticut, has seen patients with several types of "really significant" long-hauler symptoms related to sleep. Most survivors were never sick enough with COVID-19 to be hospitalized, but still struggle with long-term psychological and physiological issues.
Some develop severe insomnia — a fear of falling asleep because they think something horrible is going to happen to them, similar to what Hobart experienced.
One patient even ended up with severe depression and became suicidal months after his initial bout with COVID-19 because of his underlying fear of dying in his sleep, Kryger said. He likened the psychological impact to post-traumatic stress disorder, but with different symptoms.
Some COVID-19 survivors wake up short of breath and have low blood oxygen, indicating chronic respiratory symptoms after the initial disease. Others appear to have developed an abnormality in their central nervous system.
"I think what they have is a problem in the way their brain is controlling their breathing during sleep. In those patients, the virus has interfered with the normal control of breathing," Kryger noted.
"We don't have enough medical literature yet to understand what is going on with these patients."
It reminded Kryger of his experience as a physician in the intensive care unit during the early days of HIV, when it wasn't known how that virus worked and what its full consequences were.
During the current crisis, doctors have been discovering that besides damaging the lungs, the new coronavirus can also impact the heart, kidneys, the brain, the nervous system and the vascular system.
'Like you're drowning'
When it affects sleep, a person's entire life can be disrupted.
Franco, who asked that his last name not be used in this article for privacy reasons, is an academic in Boston who had a suspected case of COVID-19 in March. He tracked his blood oxygen levels for months because of the frightening nights he experienced during the initial course of the disease.
"When I fell asleep or started to fall asleep, it felt like I would stop breathing and my body would kick awake and I'd be gasping for air," Franco, 37 recalled about a two-week period this spring.
"It felt like you were drowning… it's terrifying."
He was never hospitalized, but he enrolled in a sleep study and wore a pulse oximeter on his own. A normal reading is usually at least 95%, but his blood oxygen levels sometimes dropped into the 80s, and once in the 70s. It rattled Franco, whose father once nicknamed him "Napoleon" for his ability to soundly fall asleep anywhere.
He only stopped wearing the pulse oximeter at night in September and is now sleeping better, but is still not back to normal. Franco felt his brain was "basically kind of like shot" for four months. He was always worried and tired.
Hobart also said his brain hasn't been functioning at the same capacity as it was before he contracted COVID-19. He feels he hasn't had a good night's rest in a long time, has been "living pretty tired" and waking up later than he normally would.
It's another long-hauler symptom Kryger is seeing in his sleep clinic: Some patients develop brain fog, weakness, fatigue and sleepiness during the day that isn't well understood yet.
"We don't know whether the brain fog is there because there's something that has been damaged in the nervous system. Or do they have a sleep disorder where they're not sleeping as much and therefore the brain fog is really a manifestation of severe sleepiness?" Kryger said.
"Right now we just don't have all of the answers."
Patients can be treated with oxygen, if that's what the issue is. If they have central sleep apnea — where the brain temporarily stops sending signals to the muscles that control breathing — a CPAP machine that keeps the airway open can help treat the problem.
Those who develop a fear of falling asleep, but don't actually have low blood oxygen at night or never stop breathing, may benefit from psychiatric counseling.
Kryger keeps watching COVID-19 survivors in his sleep clinic, trying to understand what happens to the body in the long term.
"I look at sleep as kind of the canary in the mine," he said. "Sleep is a very early indicator that there's something wrong… there are a lot of important lessons to be learned about COVID."