Ep 12: Sleep & Circadian Rhythms with Dr. Kristen Knutson


Dr. Kristen Knutson is an Anthropologist and Sleep and Circadian Researcher. She is also an Associate Professor of Neurology and Preventive Medicine and Weinberg College of Arts and Sciences.

We talked about the connection between socioeconomic status, inadequate sleep, and cardiovascular and metabolic disease.

“Inadequate sleep, whether that’s short sleep or poor sleep quality or the presence of a sleep disorder, is associated with increased risk of cardiovascular disease and metabolic disease like diabetes,” Dr. Knutson said. “We have also seen that people of lower socioeconomic status, whether that’s lower income, lower education, or racial or ethnic minorities, particularly African Americans, are more likely to have inadequate sleep. It’s been well-recognized for quite some time that these two groups, lower socioeconomic status, and racial and ethnic minorities, are also more likely to have cardiovascular and metabolic disease. So my question is whether or  not, or to what degree does poor sleep play a role in racial and ethnic or socioeconomic health disparities?”

There are a variety of reasons people of lower socioeconomic status are more likely to suffer from inadequate sleep, according to Dr. Knutson.

“Our ability to sleep… is somewhat dictated by our internal biological clocks.”

Dr. Knutson recommends employers consider the benefits of flexible scheduling around people’s natural circadian rhythms, including increased productivity and boosts in morale. “There are individual differences in the time at which people are going to be at their best. Then trying to figure out who those people are and schedule around them is going to be beneficial for both sides, both the employer and the employee. It’s a better working environment if people are working at the times that are best for them.”

I asked Dr. Knutson about her thoughts on intermittent fasting. She said there’s evidence to suggest that in addition to sleep, circadian rhythms also interplay with hunger. Circadian rhythms impact when you get hungry and also eating impacts circadian rhythms. “I think it’s a really interesting area,” Dr. Knutson said.

“One thing that’s unique about humans, is that, and the hunter-gatherer data shows this, is that we are pretty flexible when it comes to when and how we sleep. If we need to be up, we can wake ourselves up, even if we’re a little sleep-deprived. And I think that it’s going to be next-to-impossible to figure out what is the ‘natural’ human way to sleep. Naps, there’s a circadian dip in the afternoon that suggests napping may be a biologically natural phenomenon. But the extended period at night that would be required for bimodal sleep at night -- where you sleep for four hours, are awake for a little bit, and sleep some more -- that’s going to require special circumstances that allows you to have that much time to be laying in bed. And so I just don’t think we’re gonna see it in many communities today.”

I asked Dr. Knutson how people should protect their circadian rhythms.

“Keeping a regular schedule as much as possible. Staring at your phone or tablet suppresses melatonin…. Things like alcohol and caffeine… pay attention to what you’re eating and drinking, especially before bed.”

I asked Dr. Knutson for her thoughts on the consumer sleep trackers on the market today.

“They can be good and bad,” Dr. Knutson said. “They’re good if they make people more aware of their sleep patterns and therefore pay attention to if they’re not spending enough time in bed and trying to get more sleep. Just like a food diary gets you to pay attention to what you’re eating. However, if the sleep tracker is causing anxiety, because you’re feeling you’re not sleeping well enough, that could only exacerbate any sleep problems. So I think it’s a balance. It’s good to have to sort of keep track. But don’t let it drive you to an anxiety. If you have any concerns I’d raise them with a physician but I don’t want people to start to panic if their watch is telling them they’re not sleeping very well.”

Sleep myths

“We don’t think sleep need declines as we age. It might just be older people are not able to obtain as much sleep.”

“Another myth, here’s one that drives me nuts. We’re growing up thinking a healthy sleep should be, you fall asleep and you stay sound asleep for eight hours straight, and then you wake up. We know that it’s natural to wake up throughout the night. And some people don’t realize that. And so if they wake up in the middle of the night, and if they’re particularly anxious about it, that may cause concern, and then it’s a self-fulfilling prophecy that leads them to developing insomnia. Waking up occasionally during the night is not a sign of a sleep disorder. If you do wake up, don’t worry about it. Roll over and try to go back to sleep.”

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Cathy Reisenwitz