Christine Won got into sleep medicine by accident.
As an undergraduate student, she signed up for a course called "Sleep and Dreams." Almost immediately, she became fascinated by the study and prevention of sleep disorders.
"I was floored that we spend a third of our life in this state that we really don't pay attention to, and yet has so much impact on our health," said Won, now professor of medicine in the section of Pulmonary, Critical Care, and Sleep Medicine at Yale School of Medicine and the medical director of the Yale Centers for Sleep Medicine.
Today, Won's interest in sleep has come full circle: she now teaches Yale undergrads about the fascinating world of sleep medicine in a popular course called "Mystery of Sleep."
"I started getting really interested in sleep because of this class that ignited my interest," she said. "I hope that I can similarly inspire some students through this class."
Sleep is important for our health, from its restorative functions to how it helps with emotional regulation and memory consolidation. But for many people, stress can get in the way of quality sleep.
In an interview, Won discusses the importance of sleep, the sleep-stress cycle, and some of her top tips for getting a good night's rest.
The interview has been edited for length and clarity.
When you're stressed, what are the big concerns when it comes to sleep? Do people have trouble both falling and staying asleep?
Christine Won: When you're stressed, you're not going to be able to fall asleep easily, and that means you're not going to be able to achieve enough hours of sleep. Unfortunately, that means that your key sleep functions - the regeneration, the restoration, the emotional regulation, and memory consolidation - aren't going to happen.
In the other direction, how does sleeplessness fuel stress? Is there a sleep-stress cycle?
Won: When we're sleep deprived, it also magnifies our stress response. So, we could land into this vicious cycle of stress impairing sleep and then short sleep causing more stress. During sleep, we do a lot of emotional processing. Without that, we can heighten our stress levels. Our body naturally has a 24-hour circadian cycle for cortisol secretion, and it's reduced at nighttime and during sleep. If you're not getting enough sleep, then that regulation could be impaired. You could have high cortisol levels and feel more stressed for that reason.
How does disrupted sleep affect our physical and mental health?
Won: Sleep serves many functions, including physical and psychological restoration. For example, one of the functions of sleep is restoring ATP [adenosine triphosphate], the building block of cellular metabolism. If we don't get enough sleep, then we don't regenerate our energy stores for physical function. Likewise, there are a lot of toxins or byproducts that build up from cellular metabolism in the brain and during sleep that are typically eliminated or washed away by our brain's glymphatic system. If we're not getting enough sleep, that mechanism is impaired and we might build up these toxins in our brain. And that might be risk factors for cognitive function later in life.
In terms of mental health, there have been studies that show that if you're sleep deprived, your emotional processing is impaired. You tend to lean toward a negative bias in some situations. This means sleep deprived people may feel threatened or overact more easily. We all know that when we have a sleepless night, we tend to feel more irritable. Our tolerance for things becomes really low, and we're often short fused.
What are the best strategies for improving sleep, especially during stressful times?
Won: The important thing is to prioritize sleep, which means you carve out time dedicated to sleep. You have a regular sleep routine. You try to regulate your light and dark exposure, so they coordinate with your sleep behavior. You try to have routine during your days as well with mealtimes and activities. All of this is really training your body to sleep better, even under stress.
The important thing is not to get too worked up about a few sleepless nights. We're all going to have some level of impaired sleep during acute stress. What tends to happen is people build a lot of performance anxiety about sleeping, which can then lead to a vicious cycle and fuel more sleepless nights.
We need to accept that there will be some sleepless nights but still manage good sleep routines, so that when the stressor is over, we don't end up having ongoing problems with sleeping. Overall, maintaining healthy sleep habits during a stressor - while accepting the fact that stress is going to cause some sleep disturbance - will hopefully prevent acute insomnia from developing into a chronic problem.
