In Conversation: COVID-19, sleep trackers, and the immune system – the latest in sleep medicine and research
Sleep and health are intricately linked. We discussed COVID-19, sleep trackers, and the interplay between the immune system and sleep in a conversation with three sleep professionals.
Many of us are not getting the recommended amount of sleep each night. In the United States, the Centers for Disease Control and Prevention (CDC) estimate that this number stands at a third of the adult population.
To find out more about the latest in sleep science and sleep medicine, I sat down (virtually) with three sleep experts.
Aric Prather is associate professor of psychiatry and behavioral sciences at the University of California, San Francisco. He treats people living with insomnia using cognitive behavioral therapy. His research focuses on the relationship between sleep and health, particularly how sleep affects our immune system.
Afifa Shamim-Uzzaman is an associate professor of internal medicine and neurology at the University of Michigan. She is also the chief of sleep medicine at the VA Ann Arbour Healthcare System.
We discussed how COVID-19 has changed our sleep and how sleep professionals interact with their patients. We also talked about wearables — one of the latest trends in sleep — and looked at the connection between sleep, health, and our immune system.
Within minutes of introducing ourselves, we hit on the ever-present topic: the pandemic. This was clearly on everyone’s mind.
Aric told us that, anecdotally, he and his colleagues have heard that many people are experiencing early morning awakenings.
“They’re able to get to sleep, but then they wake up at 4 o’clock in the morning and are unable to get back to sleep. And that’s obviously a challenge because, as you sleep, your sleep pressure diminishes,” Aric explained.
“[Then] you don’t have that same kind of oomph of sleepiness to get back to sleep. [And] if you have these additional stressors that everyone is dealing with, whether you have kids or not, whether you have a job or not, it makes it that much more challenging to get back to sleep [and] to get that last little bit of sleep,” he continued.
“We’ve seen an association with early morning awakenings and depression and mental health issues,” Afifa commented. “You know, people tell me that they wake up in the middle of the night, and then all of a sudden, they start thinking about all the uncertainties in life right now and all the stressors that are going on, and then they can’t get back to sleep. So I think that is contributing to the early morning awakenings.”
Nancy took us through the science of early morning awakenings.
We sleep in the first part of the night because we have spent all day awake, building up a pressure to sleep. “And then in the second part of the night, we sleep more because our internal rhythm helps keep us asleep,” she explained.
Some people may be more likely to wake up in the second half of the night if their internal sleep rhythm is not as strong as someone else’s.
“The other thing that happens is every hour and a half or so, we have our REM sleep period, which is where we will typically have the most dreaming. And so, often, there’s a natural awakening after this dream sleep, and you tend to have more and longer dream periods in the second half of the night,” Nancy explained.
It is at this point that our thoughts and worries kick in and can make it difficult to go back to sleep.
Sleep, or a lack thereof, is certainly a topic that has gained in popularity in recent years. With the advent of sleep trackers, many of us can closely scrutinize the amount of shut-eye that we are getting.
But how do sleep professionals feel about this trend?
Nancy told us that she predicts that wearable sleep trackers will be one of the next hot topics in sleep research. And in her clinical practice, wearables are already featuring in her conversations with her patients.
She described a patient coming in to see her after she set them up with specialist equipment to manage their sleep apnea.
“And I ask them, ‘Well, are you sleeping better?’ And they’ll say, ‘Well, my watch says I am.’ No, that’s not what I asked,” she told us. “People can get so focused on what their watches are telling them.”
Aric recounted having people visit his clinic armed with their sleep tracker data, worried that they are not getting enough sleep and that this may fuel long term health issues, such as dementia.
To Nancy, there are good and bad aspects to wearables. They have certainly led to an increased awareness of the need for sleep. Yet few people know that the technology behind wearables is fairly basic. While sleep professionals use brain activity to measure sleep, wearables mostly rely on movement.
“I wish there [were] more awareness provided for patients to understand that aspect of it because what these wearables are really measuring is movements during sleep.” — Afifa Shamim-Uzzaman
Both Aric and Afifa called for more education around the pros and cons of wearables. “The role of sleep professionals is to provide that information, that education to help people see where [wearables] sit for someone like them. And often that is relieving, and can help people take better stock of their sleep, but without that anxiety.” Aric told us.
The pandemic has shifted concerns about our health, including worries about our sleep, to the forefront of many minds.
But is there a link between infectious diseases, such as COVID-19, and sleep? “Sleep is intimately tied to the immune system and to circadian rhythms as well,” Aric told us.
“We know a lot about this from animal research, as well as human research, focusing primarily on what happens to the immune system when people are deprived of sleep. We can see reliable changes in both the number and function of a variety of immune parameters that are key to protecting us and allowing us to thrive in the environment.”
He recounted research showing that T cells, white blood cells that are key players in our immune responses, do not divide as well when volunteers undergo sleep deprivation. Lack of sleep can also lead to a rise in the levels of proteins indicative of inflammation.
In his work, Aric has been focusing on sleep and infectious diseases. In a series of studies, he and his colleagues exposed volunteers to the rhinovirus, which can cause the common cold.
They wanted to test whether sleep had an impact on who would develop a cold. While the volunteers stayed under quarantine conditions, the team monitored their sleep using wrist actigraphy, which Aric described as “a souped-up version of a wearable.”
“In several studies, we found that people who sleep less are more likely to get sick, compared to people who sleep more. In fact, people who sleep 6 or fewer hours on average, based on wrist actigraphy are about four times more likely to get sick.”
Aric also saw that sleep has an impact on how well people respond to vaccination.
“[In] a series of different studies, we’ve found that people who sleep less mount fewer antibodies to vaccines, such as the influenza vaccine, as well as the hepatitis B vaccine,” he said.
“And right now, we’re in the process of carrying out a study looking at the COVID-19 vaccine, and whether sleep and a variety of other psychosocial behavioral factors predict how well people respond and maintain those antibody responses over time.” — Aric Prather
“I think it’s very cool stuff that they’re doing,” said Nancy in response to Aric’s research. Reflecting on her career in sleep medicine, she said that research has come a long way.
“Even 15 years ago, people would say, well, we don’t really know why you sleep. [And] what is the purpose of sleep? But research has shown that sleep is important for so many things, including your immune system.”
Another aspect of Aric’s research is the interplay between health disparities and sleep.
“Unfortunately, sleep is not evenly distributed across the population. You can see this in CDC data, across the country and [in] hotspots where there are populations or communities where [people] get less than the recommended 7 hours or more per night for an adult,” Aric explained.
“If you take that same map and you overlay social determinants of health, it’s striking how close that mirrors it. There’s a great deal of data that suggest now that individuals of color [and] individuals of low socioeconomic status don’t have the opportunity to obtain the same level of sleep as their more well off or white counterparts.”
Nancy and Afifa certainly see this mirrored in their clinical practice.
“One of the things when you’re a sleep specialist, you always ask your patients is ‘well tell me when you sleep and how many hours of sleep you get per night?’ I’ve been doing this a long time, and it never ceases to amaze me how few hours [of sleep] some people get and think that it’s okay.” — Nancy Collop
“I do think there are racial disparities that accompany that,” Nancy continued. She pointed to both the environment that people grow up in and their present circumstances as likely contributing factors. “It definitely translates to what we see in the clinic and the importance of trying to address those [factors].”
Afifa pointed to the racial disparities and age-related and sex or gender-related disparities that she sees in her work.
“What we’re also seeing is that the disparities seem to be increasing with the pandemic, and even with virtual care. We had originally thought that by being able to offer care to patients for their sleep in their homes, we’d be able to reach a lot more people,” she explained. “And absolutely, yes, we do that geographically; we’re able to reach a lot more people. But unfortunately, even geographically, not every area has good reliable internet or Wi-Fi access.”
Beyond reliable Wi-Fi coverage, there is also the issue of affordability, Afifa continued. This is a greater barrier for people from low income households or those living in marginalized communities, preventing them from getting care for their sleep problems.
To round up our conversation, I asked our experts to share their top tips for preventing poor sleep.
Afifa suggested waking up at the same time every day. “We’re not talking about if you have a sleep disorder, such as sleep apnea. If you want good healthy sleep, then I would recommend having a set wake up time [on] weekdays. If you want to vary it and sleep a little bit [more] on the weekends, no more than [an extra] half an hour.”
She told us why. “When the body wakes up, we reset our biological clocks. The day is 24 hours long, but our biological clocks are a little bit longer than 24 hours. So when we wake up every morning, we actually reset our body’s internal clocks to know when it’s time to be awake and asleep.”
For Nancy, cutting out screen time at bedtime is important for several reasons. “One is the light that it emits can be stimulating. But the other thing is what you’re going to be seeing on the screen might also be stimulating.”
She suggested turning phones, computers, and the TV off for at least an hour before bedtime.
Aric’s advice was to go to bed when you are feeling sleepy. Our beds are “an important environmental trigger for bringing on sleepiness,” he explained.
“If you get in bed and you’re not sleepy, we don’t want to create a cycle of conditioned arousal, of your body expecting to be awake in bed. He recommended getting out of bed, moving to a quiet place, and engaging in something that helps us wind down. This goes for both falling asleep at the beginning of the night and if we wake up in the middle of the night and cannot go back to sleep.
“The important thing about sleep is it’s actionable. There [are] a lot of ways that we know that can improve people’s sleep,” Aric concluded.
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