Transcription
Hey there, everybody, and welcome to today's presentation on circadian rhythms, inflammation, and mood. You never thought the three of those things were connected, did you? Well, you're going to figure out how they are in the upcoming video. I'm your host, Dr. Donnelly Snipes.
In this video, you're going to learn about circadian rhythms; it's not just your sleep cycle. And the function of circadian rhythms. You'll learn about the connection between circadian rhythms and inflammation. You'll explore the effects of disrupted circadian rhythms. You'll discuss the interaction between mood and circadian rhythms and identify ways to help people regulate their circadian rhythms. Because since mood and circadian rhythms are connected, guess what part of effective treatment is going to be? Encouraging people, helping motivate people to do what they can to regulate, or at least not dysregulate, their circadian rhythms. So let's start kind of at the beginning.
Endogenous—that means your internal—circadian rhythms are set for approximately 24 hours. Now, just let them run willy-nilly; it's not exactly 24 hours, which is why there are things in our world that help us tune our circadian rhythm to exactly 24 hours. And some of these things include light levels. So when it gets light in the morning, that's our trigger to wake up; when it's light outside, that's our trigger to be awake; and when it starts to get dusky, it's our trigger to get a little bit more tired. Well, that sounds great, but guess what? In the winter, when it gets starts getting dusky at four o'clock in the afternoon, that doesn't work so well because a lot of us are still at work. So what else helps us regulate our circadian rhythms?
Well, temperature does. When it's time to go to sleep, we typically do better in a lower temperature environment, somewhere, depending on the person, between 62 and 70 degrees. Now, a lot of research says 68 and 70 degrees; 68 degrees, I'm like sweating myself, so I prefer it on the cooler end when at all possible. So I love the winters, but I digress. During the day, obviously during the day, you see the temperature goes up outside; that is another cue to our body, as temperature rises, that it's time to be awake. But sometimes the temperature goes up overnight when a warm front is coming in, or drops suddenly during the day when a cool front comes in. So we have to have something else to help us too, and that third thing is what we're just generally going to call socialization, or your daily activity patterns. And we recognize this to a certain extent with small children. When we start teaching them to keep a routine: they come home from school, they play, they eat dinner, they take a bath, they read a story, they go to bed; and those activities start cueing the body to start winding down.
Circadian rhythm disruption is strongly associated with increased rates of several types of cancer—ouch—elevated incidence of cardiovascular or and metabolic disorders, as well as increased prevalence of behavioral and psychiatric disorders. Now, an interesting thing here is one of the common threads among all of these things is inflammation. Oh my gosh! The HPA axis—you know, this is one of my favorite topics—our stress response system serves as a pacesetter through the release of glucocorticoids, i.e., cortisol, which can override circadian rhythm timing. So your circadian rhythm is bebopping along and telling—it's kind of telling you what you should do when—but if, for some reason, the body goes into fight or flight; if cortisol level rises—cortisol levels rise for some reason—then you're not going to be as sleepy as cortisol goes up; melatonin goes down. We—when cortisol goes up, when stress goes up, it's not the time to sleep; it's not the time to relax. So it's important to kind of recognize this, and when the HPA axis is up and cortisol levels are higher, that's going to tell the circadian rhythm, "Hey, you know what? Now may not be the time to actually wind down; you know, now's the time to wind up." So it's going to alter the programming, if you will, or put on pause the programming for the circadian rhythms when you're stressed; cortisol stays higher; that prevents the release of melatonin and quality sleep; even if you do get sleep, if you're stressed, you're not going to get that quality sleep that helps clear out the adenosine; and when you don't clear out the adenosine, you start having increased pain and increased mood disorders and increased inflammation. But you're gonna see that in a few minutes.
So what do these circadian rhythms do? Most of us thought circadian rhythms just meant when we got sleepy. No, it is the primary um clock for your entire body factory. It tells the departments in your body when to, you know, turn on and when to go home for the night. And, you know, if you think of your body as a factory—we've talked about that before—and during the day when it's awake and all the workers are doing their jobs, and then in the evening when you sleep, the the floor workers go home and they rest and they get recharged for the next day, but the maintenance crew comes in, and the maintenance crew cleans up everything and clears out the adenosine, which is kind of the junk that built up during the day. Now, if the circadian rhythm is not working, then that's not going to happen, and your factory is very quickly going to fall into disrepair.
So circadian rhythms impact the digestive system; that produces proteins to match the typical timing of meals. Have you ever noticed that people who have really good circadian rhythms typically get hungry at the same time each day? You typically start getting hungry around lunchtime; this is your circadian rhythms secreting ghrelin that is telling your body, "Hey, it's lunchtime; it's time to eat." I remember when my son was an infant, you could pretty much set your clock by his circadian rhythms: when he would nap, when he would eat, when he would do these various things. Circadian rhythms impact your hunger levels by regulating the release of that ghrelin. They also regulate thyroid function and metabolism, and indirectly weight through the regulation of blood sugar and cholesterol. When you are awake, your circadian rhythms are helping you um fuel your body, which means you're going to have more blood sugar available. When you are supposed to be sleeping, you know your your circadian rhythms alter your metabolic rate; the gut microbiome composition is also impacted by circadian rhythms; the workers, if you will, that are recruited in the gut differ from day to night; they differ based on the time of day, which is where that circadian rhythm, the scheduler, comes in. The immune system, inflammation, and DNA repair—all are, which are involved in preventing cancer and helping you stay healthy—are also impacted by the circadian rhythm. The immune system is going to do different things at different times of day; you know, when you're sleeping and you're not having to use a lot of energy to do other stuff, the body can rest and repair and recharge. During the day, it's not as much focused on that, for example. So when your circadian rhythms are aligned, if you will, then during the day the immune system is not going to get as much attention, and at night it will. But if your circadian rhythms are messed up, then the body goes, "Okay, when are we exactly supposed to repair everything? Um, help me find a time."
Circadian rhythms impact your endocrine system, regulating cortisol to suit your normal energy expenditure. We have something called the awakening response; in the morning, we typically wake up, and your cortisol levels are supposed to be highest when you wake up. Now, a lot of people are going, "Uh, cortisol, stress hormone, high, yuck, no," we want it to be at that normative high; we don't want it overly high, but if you didn't have that increased level of cortisol, you wouldn't have the energy to get up. So that awakening response is your circadian rhythm kind of ringing your own internal uh alarm clock and saying, "Hey, it's time to get up and get energized for the day." Blood pressure is regulated; your blood pressure goes up during the day to help you accomplish the activities of the day, and when you are completely asleep, when you are completely at rest, your blood pressure goes down. It helps regulate sleep through the secretion of melatonin; circadian rhythms—as cortisol drops—then your body gets the message that, "Hey, it's time to start converting serotonin to melatonin," and that's when you start seeing the person start to get sleepy. Circadian rhythms also promote cognition through activities that promote the clearance of adenosine and neuronal repair. Now, we can't clear adenosine from our brains when during the day; that's not what happens; what happens is when we're in that deep sleep, then the the body is able to clear that adenosine out and repair the neurons. But if we're not able to get that deep sleep, if your circadian rhythms are out of whack and not helping you secrete melatonin, not helping you get good sleep, then you're not going to be able to do that; that's going to contribute to the memory and attention problems, in the brain fog.
Circadian rhythms regulate the reproductive system, influencing the release of gonadal hormones and vice versa; your gonadal hormones also influence your circadian rhythms. And, you know, the most simple ex example of this is in the female reproductive system; we see that the female goes through menstruation at a particular interval, every 28 to 30 days, and that is regulated by the circadian rhythm. But what happens if that person gets excessively stressed? Well, when we have excessive stress, it alters gonadal hormones; those gonadal hormones alter the circadian rhythm of that reproductive system, so then the person may become amenorrheic; they may not have their period for until the stress passes.
Circadian rhythms are influenced in part, as I mentioned, by light levels; so it's regulated in part by the suprachiasmatic nucleus, or the SCN, in the hypothalamus, which gets input from light. Now, blue light, which is about 6,500 Kelvin in temperature, in moderation during the day, improves mood, alertness, and memory; so that's great. Now, you don't want to stare into the sun—gosh, no—and too much blue light can be really hard on on your system, and it can be really stressful. So they say blue light in moderation and during the day, not at night when you're trying to wind down. Blue light communicates to your to your brain, your circadian rhythms, that, "Hey, it's time to be awake." Blue blocker lenses that you can get in your reading glasses or in your sunglasses can block up to 40 percent of blue light, and I think you can get some blue blocker lenses, especially like sunglasses, that block even more than that. But it's important to recognize, it's probably not blocking everything. You can also get filters for your or apps that filter the light on your mobile devices; you can get filters for your television, for your computer, that you can enact at a certain time each day in order to reduce your blue light exposure.
Yellow light, which is typically like candlelight, is about 2200 Kelvin, and that's your temperature; that doesn't have anything to do with the brightness of it; that's how warm or how cool it is. And I recommend for a lot of my patients, and I do it myself—I have bulbs in my bedroom, you know, that's where I go to wind down, I read a book or whatever—but I have that set at—I have yellow bulbs in there that are between 2000 and 2200 Kelvin, and it gives a a warm kind of yellow glow, but it's bright enough that you can actually read.
Exercise is another cue; this is one of those socialization or lifestyle activities that help set the circadian rhythms. Low-intensity exercise reduces cortisol and makes serotonin more available, which can help improve sleep. Now, low-intensity exercise is something like walking on a treadmill or walking around the neighborhood; it's not getting up into target heart rate training zone and, you know, hoofing it. High-intensity exercise releases endorphins and serotonin, so it's important to figure out, "What am I trying to do?" Now, some people will do high-intensity exercise, and they will just, you know, wear themselves out—wear out the stresses of the day, as some people say—and they go home and they are just totally relaxed. And so it depends on you how exercise totally affects your your circadian rhythms, but it is important to recognize that exercise does directly influence cortisol, which directly influences your circadian rhythms and your sleep.
Social activity, socialization, whether it is in real life or even—they found—uh, texting and engaging with people virtually can also, to a certain extent, enhance oxytocin and increase awakeness. It will depend on the person, on the setting, on the activity, exactly how it influences your circadian rhythms. Obviously, if your significant other is giving you a back rub and helping you relax, that's different than if you're sitting there talking, or if you're playing checkers or something. But social activity tends to enhance oxytocin, which generally is associated with increased awakeness. Body temperature increases also signal awakeness and decrease signals for sleep and relaxation. Well, this can be a real bugaboo if you're having hot flashes, let me tell you, but it is important to recognize that your body temperature likely impacts your circadian rhythm. So if you are overly warm, chances of getting super sleepy are, for most people, reduced.
So let's talk about reciprocal influences and mood. I've talked—been talking—so far about what the circadian rhythm does, but it's important to recognize that the circadian rhythm is also impacted by everything that goes on with the person and in the body. So it impacts and it's impacted by—it's a two-way street. Changes in blood sugar regulation as a result of circadian rhythm disruption can contribute to feelings of anxiety or depression. Inflammation can cause HPA axis dysregulation via hypercortisolism-related hyperglycemia. So why is that important? When people are stressed, when people have high levels of anxiety and their cortisol levels are high, that keeps their HPA axis activated, which disrupts—which hijacks or turns off or whatever you want to say—the programming of the circadian rhythms. So circadian rhythms start to get a little bit wonky when uh when people are stressed, and when circadian rhythms are wonky, it can contribute to inflammation and contribute to stress. There are alterations in the gut microbiome; when the circadian rhythm does it, it has a specific purpose in mind, but when we're stressed, for example, that—through the vagus nerve—alters the composition of the gut microbiome. So a different signal gets sent to the brain and communicates, "Hey, you know what? Actually, not time to rest right now, or actually it's time to get really stressed right now, so we need to ramp up that cortisol." Both of these alterations—in gut microbiome and inflammation and changes in blood sugar—are associated with symptoms of anxiety and depression.
Adenosine buildup—remember I said that that was kind of the garbage that builds up as a result of thinking and stuff throughout the day?—well, if we don't clear that adenosine out when we wake up the next morning, we feel foggy, we feel groggy, we have difficulty concentrating; and adenosine buildup is also associated with symptoms of anxiety and depression, especially those cognitive symptoms. Likewise, they did some research and they found out that adenosine antagonists—so things that suppress adenosine—improved anxiety and depressive symptoms and behaviors. So we're starting to recognize that, "Hey, there's this whole other chemical out there that may be related to symptoms of anxiety and depression." Changes in eating habits—when people are depressed, for example, they may eat to self-soothe; when they're anxious, they may eat to self-soothe, which is going to alter their circadian rhythms; and if the circadian rhythms are altered by something else, then the release of ghrelin to prompt someone to eat may be altered. So a lot of people on on shift work have difficulty knowing when to eat because there's the circadian rhythms; their daily schedules change regularly, if not daily, so then the circadian rhythm's going, "Yeah, I'm not sure when I'm supposed to do anything," and you can kind of see the circadian rhythm throwing its hands up and going, "Screw it, eat when you want; I don't know."
Inflammation also influences and is influenced by the circadian rhythms. Interestingly, I found—and I I knew that inflammation was associated with anxiety and depression—but they also found that inflammation uh in the body can increase or is associated with symptoms of bipolar disorder, as well as borderline personality. Now, why might this be? Well, people with bipolar disorder, especially if they're in a manic phase—obviously that's kind of overriding the circadian rhythms because they don't feel like they have a need to sleep—and then when they're in the depressive phase, they have difficulty being awake. So we see that there's an alteration in cortisol and potentially blood sugar regulation in bipolar disorder. In people with borderline personality, we often see high levels of stress and anxiety and abandonment fears, so their HPA axis is often way high, so their cortisol levels often stay way high until their body becomes resistant to the cortisol, then it's way low, and that will alter the circadian rhythms. So it does make sense. Now, when cortisol loses its abilities—when the tissues become insensitive or resistant to cortisol—then we start seeing systemic inflammation. So people who are under chronic stress—and a lot of times that's evidence through anxiety, depression, or behaviors indicative of borderline personality or even bipolar—but when people's uh receptors—cortisol receptors—are being overexposed to cortisol, then the tissues become tolerant to it, resistant to it; cortisol is a steroid; cortisol typically is anti-inflammatory in nature, but when the tissues quit responding to it, then you start seeing systemic inflammation. So this is why we see a connection between a lot of psychiatric issues and inflammation, because psychiatric issues are often associated with high cortisol and alterations and cortisol um HPA axis functioning, which means that cortisol loses—for a lot of these people—loses its effectiveness at suppressing inflammation.
Interesting little tidbit. And another really interesting thing is there are actually chronobiological—circadian rhythm—changes in pain perception over the day. And when you think about it, it actually does make sense because, assuming the system is functioning well, as cortisol goes up, it should act as an anti-inflammatory and suppress pain; and then as cortisol goes down, like during the night when you're asleep and hopefully not even aware of it, pain perception is highest because inflammation tends to go up more, and that's when the immune system is actually doing more of its work; you know, it can focus on repairing the body while you're sleeping. So that's kind of cool. As uh remember that inflammation in and of itself is not bad; that's your body saying, "Hey, there's an injury; we need to bring in the cavalry to repair it." So if we didn't have any inflammation ever, we wouldn't be bringing in the cavalry when there were two spots of injury. So what the circadian rhythm does is it says, "Okay, let's, you know, hold off on all the repair, hold off on all the maintenance of the factory until the workers go home, and then we can come in and, you know, bring in the inflammation, bring in the cleaning crew to fix what's going on." So it's it's cool system.
Main influences are circadian rhythms; external influences or exogenous influences: light—we already talked about—you you want to have some exposure to blue light during the day and minimal exposure to blue light when you're trying to get to sleep; temperature—cooler when you're trying to sleep, warmer when you're trying to do stuff; feeding—when you eat, it alters your circadian rhythms to a certain extent because, along with ghrelin, which is your hunger hormone, there is leptin, which is your satiation hormone, and the circadian rhythm helps send those out. So when you eat, it can trigger a cascade of responses; it triggers alterations in your blood sugar levels and everything else; remember I said that the circadian rhythm affected the digestive system and basically primed it—got it ready to receive the food that you were getting ready to eat—so when you eat, if it's not when you're supposed to be eating, the circadian rhythm goes, "Okay, okay, hold on a second; let me let me take care of that," so it's having to adjust to you; and then activities and lifestyle routines.
Internally, pain and inflammation influences circadian rhythms because if you are in pain, if you're experiencing chronic inflammation, that's going to ramp up that HPA axis because pain is stressful, and that stress can alter the circadian rhythm. When you're not getting good sleep, then it's going to ultimately intensify the pain, so it's a negative spiral that we need to figure out how to break. Stress or distress levels also influence circadian rhythms by keeping cortisol levels high, and thyroid and gonadal hormone levels can also impact circadian rhythms. If you are hypothyroid, hyperthyroid; as we age, our gonadal hormone levels change, and that can also impact our circadian rhythms. So it's important as clinicians that we don't just assume that everything that's causing people's distress has to do with their cognitions; we need to recognize the importance of sleep, the importance of circadian rhythms in regulating the neurotransmitters and the hormones in the body so the person can achieve their maximal quality of life.
How might mood influence circadian rhythms? Well, we kind of talked about that, but anxiety-related ruminations keep cortisol levels high. If you're just stressing out, you're going to keep your cortisol levels high, and it's going to be hard to quiet your mind so you can relax and get to sleep. Emotional eating will keep you eating at the non-program times, if you will, and can throw the circadian rhythm out of whack. Hypervigilance, preventing adequate sleep and or hyperalertness—so people who've experienced trauma, for example, may have a heightened orienting reflex; they hear more, they're more sensitive to what's going on around them, so it's harder for them to sleep; it's like a soldier sleeping in a foxhole instead of a child sleeping in a super secure safe place where they feel loved and comforted. I don't know what the alternative to that is. Um, we want to recognize that a person with PTSD is probably not getting adequate quality sleep. Cortisol alterations and depression—you know, when somebody is depressed, what do they typically do? They typically don't move a lot; they have what the DSM calls psychomotor retardation; they typically don't go outside a lot, so their routine is disrupted, their oxygenation is reduced, their exposure to blue light during the day is reduced, their exposure to dim light the rest of the time is increased. So the circadian rhythms again start getting thrown out of whack because if feeding, for example, is partially dependent on light levels, partially dependent on temperature levels, and that's never changing, then the body's going, "Is it time to eat?" Think about those days when it is really really gray outside; you wake up in the morning and it stays kind of just dusky or Donny or gray looking all day long, and you feel like it's evening even though it's 10 in the morning, and you're exhausted; you're like, "Oh, I'm ready to go to bed." That's that circadian rhythm responding to an aberration in the light levels.
Other causes of circadian rhythm disruption: 24-hour caregiving or on calls—not saying that you can avoid these if you have an infant home or even an older child; sometimes they're going to wake you up, and that can disrupt circadian rhythms. If you are caring for a sick family member or friend or pet or um whatever, you know, you may have 24-hour caregiving duties, and it's important to try to figure out how to best manage your circadian rhythms; it may not be perfect, there may be times when you have to go a week or two weeks where you are, you know, having a a wonky circadian rhythm because that's what that person needs, or you're on call for two weeks out of the month, but it's important as soon as you can to get back onto a schedule. Shift work—some people work midnight shift, and that's just what they do. One of the most important things and most ignored things that people can do if they're on shift work is to keep their schedule consistent, and this is hard, especially if you've got kids at home. If you're working midnight shift to keep your schedule consistent and be up all night long, you know, see them for breakfast and before they go off to school, and then you're going to bed, but it is so much better for your health, for your mental health, and ultimately for your energy levels and your ability to focus on them when you are together, so you have that quality time. Keeping your schedule consistent and try to get to bed before daylight; if you see that early morning light, if you see dawn, then it triggers the awakening cycle, and and that's—some people can't avoid that; if you are working a shift that gets off at seven in the morning, you're probably going to see the morning light; it's unfortunate um that that has to be the case, but minimize your exposure to light as much as possible in the morning before you go to bed if you're on that midnight shift. Time zone changes—and this is more applicable to people who are airline pilots or cross-country truck drivers—but time zone changes can really mess with your circadian rhythms, and it's important to, if you can, to try to maintain a consistent one. So even though the day—May—day hours may change—so on the East Coast it's noon and on the West Coast it's 9 a.m.—um, okay, well, if you spend most of your time on the East Coast, then you're going to try to adjust your activities when you're on the West Coast to that time zone. So if you normally eat at 9:00 a.m. on the East Coast, then you will try to eat at 6:00 a.m. on the West Coast and vice versa; they've found that that can be helpful. Now, some people will say, "No, I prefer to use the light levels to adjust my schedule," and, you know, that's a personal choice; whatever works for you.
Poor sleep habits and poor sleep—sleep quality—also disrupt circadian rhythms; taking long naps, especially if you start to get into deep sleep—so naps more than 45 minutes can disrupt circadian rhythms; drinking too much in the way of fluids before going to bed, so you got to get up and pee three times during the night, disrupts your sleep and your circadian rhythms; and noise can disrupt your sleep and your circadian rhythms. For noise, you can put in um uh earplugs if you need to; that's one thing; you can use a white noise machine, whatever you can do; and then with fluids, try to limit your fluids and you you know how long it takes fluids to pass through you, so try to limit your fluids so you're not going to have to get up throughout the night. Pain can also disrupt your your sleep as well as your circadian rhythms; pain during the day artificially increases cortisol levels; pain at night may wake you up. So pay attention to your ergonomics during the day so you're not causing yourself extra pain at night. If you wake up with pain or you're having difficulty getting to sleep, guided imagery, TENS units may be helpful; physical therapy can be helpful to modulate or moderate pain during a recovery process, as can ice, heat, or massage. Know what temperatures work best for you; not everybody does well at 62 degrees; I love it; not everybody does. Know what temperatures work best for you to relax and get sleepy versus which temperatures help you be awake. When I was in graduate school, we had classes in the basement of the hospital, and it was always the opposite temperature there as it was outside. So if it was 80 degrees outside, it was 60 degrees in the basement; well, 60 degrees is great for sleeping, but not so good for sitting through class, and a lot of us would be, you know, kind of getting groggy and sleepy and trying to stay awake; well, that was part of the circadian rhythm dysfunction because the circadian rhythms are going, "Okay, we're cooling the body down; we're sitting still; is it time to sleep?" Light is also another cause of circadian rhythm disruption, either artificial light—having too much blue light—or just changes in day length, which is why it's important to know that it's not just day length that sets your circadian rhythms; you can use artificial light, you can use social activities, you can use temperature; there are a lot of things you can do to help keep yourself regulated.
Medication, caffeine, and alcohol—we'll just kind of put all those together—substances that you ingest can also disrupt your circadian rhythm; if they are depressants, they may make you feel sleepy too soon; they may suppress your appetite; they may slow things down; likewise, they may rev things up. So we need to understand that and figure out like if somebody's taking an antipsychotic, which we know typically makes people sleepy, when is it best for them to take it in order to maintain their circadian rhythms and be awake and alert and able to think clearly and enjoy life versus sleep. So one client I worked with, for example, was on an atypical antipsychotic, and working with their psychiatrist found out that the best time for her to take it was at four in the afternoon; and if she took it at four, then by the time she was ready to go to bed, it was, you know, in full effect, and she was at her sleepiest; and then by the time she woke up the next morning, the sleepy effects had somewhat worn off.
Hormone fluctuations—whether it's due to pregnancy or postpartum or adolescence or even aging—can also cause changes in circadian rhythms, so it's important to recognize that, and that's not just—that's for people regardless of biological gender. TBI—traumatic brain injury—or neurodegenerative disorders, especially ones that impact the hypothalamus, will also impact the circadian rhythms. So it's important to recognize that we see people who have these disorders start to become more restless, start to have more difficulty sleeping; they're up and down all night long, um, and some of that is due to disruptions in their circadian rhythm.
Sleep habits and light significantly impact circadian rhythms, but they are not the only things; even if you're more spontaneous, it's still important to have a sleep routine and practice good sleep hygiene. Additionally, recognizing the impact of medications, time changes, neurotransmitter and hormone balances can help reduce the impact of circadian rhythm changes; and recognizing the impact that things like anxiety, depression, bipolar, or even changes in environments or stressors have on the circadian rhythm—you know, it's it's a two-way street; it's not just the circadian rhythm controlling everything; circadian rhythm is also impacted by everything. So when we're working with people who have, for example, mood disorders, helping them understand how flare-ups in their symptoms may impact their circadian rhythm and why it's important to do as much as they can to modulate their circadian rhythm in order to enhance their overall recovery.