Sleep studies

Marquette professor researches the rhythms of our nights

Dr. Jennifer Evans was awarded a $1.7 million grant from the National Institutes of Health to research biological rhythms on human health. Evans, Assistant Professor of Biomedical Sciences in MU Health Sciences, recently spoke with Provost Dan Myers on the Illuminating Intellect podcast about the master clock in our brain, the importance of keeping a regular schedule and more. Below is an excerpt of the podcast.

Dr. Evans: When the field really started to gain momentum in the early 70’s, this was when we discovered a small part of the brain that acts as a master clock. At that time and going forward until the late 90s, it was thought that this was the primary and only major clock in your brain. But since then, we’ve realized that the molecular gears of the clock and the ability to track hours of the day is actually an inherent property of almost every cell in your body. Everything from your skin cells to your lung cells to your brain cells to every tissue of your body has the ability to act like a clock and changes with the hours of the day in terms of controlling what the cells are doing and adjusting to the environment.

So I think given this plurality of biological clock cells, a key question that the field needs to address is how do these different cells communicate with one another in order to remain a harmonious unit. And that’s really what my research is focused on — understanding how different types of cells can coordinate their rhythms and clocks to produce a cohesive system.

Dr. Myers: So my fingernails and my liver and my brain, they’re somehow all keeping in sync with each other so that they know that I need to be active during some part of the day and I need to be less active in other parts and I need to be sleeping in some parts. They’re all somehow working together and telling each other that?

Dr. Evans: The takeaway is that every tissue has a clock. And that clock is tuned to do things at specific times that’s relevant for that tissue. So while your skin cells and your liver cells and your lung cells all have clocks, the way that clock functions is slightly different in each of those tissues to support the function of that tissue.

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So your pancreas clock functions a little differently so that way insulin production is adjusted to your time of meal intake. Whereas the cells of your brain have a different function so the clocks in those cells operate slightly differently and control different types of cellular processes. And so the way that they coordinate is largely through this master clock in the brain.

Each cell can sustain timekeeping all by itself but it needs to be coordinated with the other tissues in the body and with the environment. In large part, it does this through receiving signals from basically a dictator clock in the brain that receives the signals from the environment, processes them, and sort of keeps everybody in line.

Dr. Myers: So is it better for me as a person — for my health and my cognitive functioning — to be on a sort of regular schedule where I’m sleeping during the same time each day as opposed to mixing it up and staying up late sometimes, going running at 5 am versus the next day at 9 pm? What is good for me in terms of that kind of rhythm of life?

Dr. Evans: It’s always dangerous to give prescriptions to individuals and as a scientist I tend to avoid trying to do those things. But I think here the research really speaks to the importance of keeping regular schedules because irregularity disrupts the functions of these clocks.

Listen to the full episode on Soundcloud.

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