SEGMENT 1: Dr. Phyllis Zee discusses the relationship between sleep and cardiovascular disease and obesity

Dr. Gary H. Gibbons, Director, National Heart, Lung, and Blood Institute:  Hello. I’m Gary Gibbons, today my guest is Doctor Phyllis Zee, Associate Director of the Center for Sleep and Circadian Biology at Northwestern University and a Professor at the Northwestern University Institute for Neuroscience.  Dr. Zee is one of our leading circadian biology and sleep researchers and at the NHLBI we’ve come to appreciate how prevalent issues of sleep and wakefulness disturbances are among the American public affecting over 50 million US adults, and how much we’re learning increasingly in how circadian biology and – plays an important role in how blood pressure is regulated, the predisposition to obesity, diabetes, heart attacks and strokes, and so this represents a very important and increasingly important part of the NHLBI research portfolio and we’re delighted to have one of the leading experts to talk about it today.  

Dr. Zee, could you start off by just giving us a sense about these connections between sleep and the lack thereof and particular diseases or categories of diseases, and what do you find in your particular research that’s most intriguing or provocative about this connection, most recently in your portfolio?

Dr. Phyllis Zee, Northwestern University:  Absolutely, happy to do that.  In the last decade or so, there’s really been an explosion of knowledge both from experimental studies, laboratory-based studies as well as studies – population-based studies, epidemiological studies showing a very strong link between sleep quality and mostly – initially was about sleep duration with that of a risk – increasing the risk for cardiovascular disorders such as high blood pressure, hypertension, and I think even stronger data over the years with the relationship with weight, obesity and glucose intolerance.  When sleep is altered it changes appetite regulation, it changes – a failure of metabolism both at the molecular as well as at a cellular level and those effects – and also inflammation, and those effects may be what links or mediates the interaction between sleep and that of these multiple health outcomes that you just mentioned Dr. Gibbons.

Dr. Gibbons:  Absolutely, and what are we learning about perhaps some of the mediator pathways?  Are there linkages that are telling us something about how it affects a metabolism that might predispose it to conditions like diabetes or linkages to the immune system and inflammatory process?  Do we have insights into some of the molecular pathways behind this?

Dr. Zee:  The mechanisms that link the poor sleep quality or sleep duration with both cardiovascular risk as well as risk for metabolic disorders is not fully understood.  However, several lines of research, especially from laboratory studies, have shown– at least from the physiological standpoint– that when sleep is altered, it can alter neurological brain regions that affect appetite regulation, for example, both in the hypothalamus as well as in areas like the nucleus accumbens where you’re looking at perhaps addictive properties.  At a physiology level, sleep curtailment, for example, has been shown to alter glucose utilization at the cellular level.  There’s also studies now that show that the relationship between sleep and also circadian rhythms and circadian gene regulation with that of mitochondrial metabolism.  So really ranging from the – from whether you’re talking about mitochondrial metabolism, cellular metabolism, both on the molecular and cellular levels, that sleep and also – now, the interaction with circadian rhythm and circadian timing appears to play a very basic role in the regulation of metabolism, for example.

Dr. Gibbons:  That’s very interesting.