In Conversation

Dr. Meir Kryger on his ‘adventure’ of studying sleep

Kryger, a pioneer in the field of sleep medicine, discusses his career, the history of sleep studies, and how he’s helping to fight COVID-19.
Illustration of a woman sleeping


The COVID-19 pandemic has been the stuff that nightmares are made of — literally. Many Americans are reporting related sleep disturbances, including interrupted sleep, insomnia, and vivid nightmares.

That’s where Yale’s Dr. Meir Kryger comes in: A pioneer in the field of sleep medicine, he published the seminal textbook on the subject, “Principles and Practice of Sleep Medicine.”

Kryger, professor of medicine (pulmonary) and clinical professor of nursing, recently participated in a virtual press conference sponsored by Yale’s Office of Public Affairs & Communications, during which he spoke about the long history of sleep disorders, gave tips about how to get a better night’s sleep — even during a pandemic — and discussed the moment he had a sudden insight about a COVID-19 risk related to a common sleep disorder. 

What follows is an edited version of his remarks.

How long have you been studying sleep? What led you to study sleep?

I’ve been studying sleep since I was a medical resident in 1974. I had a patient who had a sleep problem but there was nothing known about sleep disturbances at the time, and nothing in the literature to explain what he had. The man had sleep apnea, which had not even been described in North America. I went on to publish the first paper in North America on sleep apnea. For me, studying sleep has been an adventure to see what I could learn and now to watch the field expand. 

When were sleep disturbances first documented?

Sleep disorders have been around for thousands of years. Descriptions of sleep apnea date back to 325 B.C., where historians describe a tyrant named Dionysius, a contemporary of Alexander the Great who clearly suffered from what we now know to be sleep apnea. Also, Charles Dickens describes a young boy with sleep apnea in his first novel, “The Posthumous Papers of the Pickwick Club,” published in 1836. 

What are some of the trends you are noticing in the sleep and dream habits of people during quarantine?

Due to the stress of the pandemic, many people are experiencing unstable sleep. People are having very vivid dreams, and they are remembering their dreams more than they have before. You remember a dream if you wake up either during or right after the dream. And, if the dream is frightening it will scare you. If someone has a repetitive nightmare and they wake up in a panic, that may be a sign of post-traumatic stress disorder (PTSD). 

How can people calm themselves down after a nightmare and fall back asleep?

People need to realize that a nightmare is a dream, and a dream isn’t real. People who are in moderately good health dream three to five times a night. It is important to remember that there is no message in your dream. By the time you reach adulthood, you’ve had many, many thousands of dreams. Once you start to dissect your dream it takes on undue significance and might start the cascade of insomnia. 

What are your suggestions for better sleep through the night during the pandemic and beyond?

Number one: Turn off your electronics two hours before going to bed. That includes televisions, iPads, and cell phones. Number two: Get rid of your alarm clock. The last thing you want to do is have a clock that is next to your head at night reminding you that you aren’t sleeping. 

Particularly now, during the pandemic, people have broken up their usual rituals and sleep patterns. They are staying up very late and sleeping later. It’s important to keep a normal routine even during quarantine. The brain loves regularity. It loves that you go to bed in the evening at the same time and that you wake up in the morning at the same time. Once your schedule gets thrown off it is very difficult to get back onto a normal routine. 

You recently developed a new circuit device for sleep apnea patients. How can it curb the spread of COVID-19? 

Sleep apnea is a condition where people repeatedly stop breathing during the night, and when they do this, their blood oxygen drops. We treat that with continuous positive airway pressure, or CPAP. People with sleep apnea wear a mask that is connected by a hose to a device the size of a small toaster oven. The machine generates pressure to keep their breathing passages open. The CPAP system has filters that ensure that the air going into the device is clean. 

Up to now, we never worried about what was in the air coming out of the patient; we only worried about what was going into the patient. Early on in this pandemic, I started to think these systems are leaky, and the air coming from a sleep apnea patient with COVID-19 might be full of the virus. A colleague at Harvard, Dr. Robert Thomas, and I redesigned the circuit between the patient and the machine so that the air leaving the patient — to the best of our ability — is filtered to minimize the amount of virus in the air. This research will have long term impact in thinking about the spread of other infections and viruses as well.

Share this with Facebook Share this with X Share this with LinkedIn Share this with Email Print this

Media Contact

Bess Connolly :,