Bonus clip from I’ve Got (Circadian Rhythm), with Dr. Emily Manoogian.
Thank you for downloading this bonus clip from This Is Your Brain. In this excerpt Dr. Emily Manoogian discusses chronotypes (like if you are an early bird or a night owl), and how circadian rhythms change as we age, and tips to deal with jet lag.
Phil Stieg: Does circadian rhythm change with age? Because they always say that older people don’t need as much sleep. So it’s a 24 hours cycle, but different how?
Emily Manoogian: Yes. So your circadian rhythms do change with age and we can all probably kind of see it if you look at, either think back on your own life, or look to those around you.
So there’s a term called chronotype. So chronotype is really how you relate to the environment around you. And in more common terms, are you an early person or a late person? And this is because again, we don’t all have exactly 24 hour rhythms. Some are slightly longer, some are slightly shorter. The shorter ones are morning people, the later ones are evening people. So there is a biological basis to this. But you don’t just have one time throughout your whole life.
So when you’re a newborn, your SCN isn’t fully formed until you’re almost six months old. Which is why newborn babies have no circadian rhythms at all and how parents deal with that, myself included. I don’t know how you get through it. It’s horrible. But once they do form rhythms, they actually have an earlier chronotype in that earlier phase of their life than they do later. And it really starts to delay once you hit puberty, is generally kind of the tipping point, especially into the late teens.
This gets into why high school start times should be later. And then this starts to change. You start to get a little bit earlier. For women it happens a little bit quicker than for men. But it seems to be in the early 20s women start to get a little earlier and a little earlier. Men, it seems to be a little more like mid-to-late twenties. And then you kind of even out to what, your standard chronotype would be for quite a while and you’re either twenties or thirties and then you’re there for a bit. As you continue to age though, you actually do become a little bit earlier again. And so we do see if you look, on average, a lot of elderly do report having an earlier chronotype than they would have earlier in their life.
The sleep factor, though, I actually don’t think it’s a lack of need for sleep, I think it’s a lack of ability to sleep. And that gets back into your brain kind of not always regulating things as well as maybe it should as you’re aging. And I think the sleep need stays there. It might shift slightly. And, I mean, these are not huge shifts, hours or hour or two, but I don’t think the need goes away. It’s really just a matter of being able to keep consolidated sleep that’s a challenge.
Phil Stieg: For those of us that have to work around the world and try to produce shows like this, are there any tricks that we can use to minimize the effect of circadian rhythm on individuals on the other side of the world?
Emily Manoogian: Yeah, absolutely. So if you’re trying to make a big time zone change, really, I think what you can do is try to use all those cues that we talked about light, food, and exercise to tell your body what the new time of day is.
There’s some theories that fasting on the plane can help, and then eating at the correct time once you’re there. So if it’s morning, start eating. If it’s nighttime and it’s not time to eat, then stop.
Phil Stieg: So fast on the plane?
Emily Manoogian: Yeah, there’s some stuff there. It depends on when you’re flying as well. If you’re flying during their day, then you might want to go ahead and eat and kind of stay on that schedule. But I would say once you’re there, it’s just try to get your body on that schedule as fast as possible. So get bright light in the morning, dim at night, eat at the correct times of the new schedule, be active during that time.
If you want to get advanced about it, you can try to make a little bit of a shift before you leave. You can shift about an hour a day. You can try to slowly shift your schedule before you would make a big change. So it’s not as big of a shift. So that might mean waking up a half an hour, 45 minutes earlier each day for a few days in a row. And again, going to sleep earlier and switching your food. Just shifting your entire schedule a little bit each day for a few days before you leave can sometimes take the edge off for people. That’s just more or less feasible, depending on your life.
Phil Stieg: What I find most amazing is when I got my PhD, there wasn’t even a field of neuroscience yet. And now we’ve developed an area of chronobiology, a subset of neuroscience. It’s amazing how we’ve progressed. It’s fantastic.
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