MH@H Mental Health

Doing the Circadian Rhythm Dance

human Circadian rhythm clock

Our bodies’ inner clock is quite remarkable. It can work really well sometimes, while at other times, it gets completely thrown off. So what is the circadian rhythm, and how does it work?

What is it?

According to Wikipedia, a circadian rhythm lasts approximately 24 hours and persists even in the absence of variations in light and dark; can be reset through changing the environmental conditions one is exposed to; and the body adjusts temperature as part of the rhythm.  Even certain bacteria display circadian rhythms, so this is not something that’s unique to humans.

Light and dark play an important role in the circadian rhythm.  There’s a direct connection between specialized photosensitive receptors in the retinas of the eyes and the suprachiasmatic nucleus (SCN) in the brain.  The SCN acts as a regulator of the circadian rhythm, triggering the pineal gland to release melatonin when it’s nearing time for sleep.  

I was curious about how this might affect my blind blogging friends, so I did a bit more digging.  The specialized ganglion cells that pick up light in the retina are functionally distinct from the photoreceptor cells used for vision, so a small proportion of people who are totally blind and the majority of people who have some degree of light perception maintain a normal light-dependent circadian rhythm.

In mice, mutations in the “clock gene” can lead to overeating and obesity, with increased risk for diabetes.  In humans, shift work and other activities that disrupt the circadian rhythm can contribute to weight gain, heart problems, and inflammatory conditions.  Excessive screen time on electronics is another factor that can disrupt the circadian rhythm.  I work night shifts for one of my jobs, and I worry sometimes about the potential health effects. Still, I suspect sporadic shifts like I do are a lot less harmful than doing full-time nights, which would knock out the circadian rhythm entirely.

Life vs. circadian rhythm

I found the graphic above on Wikipedia.  With it approaching winter where I live, it’s dark by 5pm, so the clock requires a bit of shifting.  But even taking that into account, I’m very much abnormal.  A typical day for me is to go to bed at 5:30pm (with the assistance of my regular bedtime meds, of course), and then sleep until 1 or 2am.  I fully recognize how bizarre that is, and a lot of people are just getting to bed when I’m waking up.  But if I was living in caveman times (or at least pre-fire caveman times), I’d be going to bed at 5:30 anyway because that’s when my melatonin would be peaking.  Getting up when I do, my alertness is peaking when everyone else is asleep.  My peak coordination time apparently happens when other people are spending some quality time on the toilet.

The last time I went off my medication, what I noticed the most was that I couldn’t sleep.  I tried melatonin supplements and it did sweet bugger all.   Taking oral supplements is probably a pretty poor substitute for your brain getting it right in the first place.  I think my circadian rhythm is working the best it can, because I definitely get sleepy when it gets dark, but that’s not enough on its own to overcome depression’s desire to not let me sleep at all.  That’s why I definitely need me some drugs.

Do you maintain a consistent circadian rhythm?

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15 thoughts on “Doing the Circadian Rhythm Dance”

  1. Fascinating stuff! I had no idea how much hormone levels etc. vary over the day. As someone with poor hand-eye coordination, it’s good to know that my best chance at ball games is around 3.00pm.

    For a long time – years – I was basically nocturnal. I was too depressed to work. Initially insomnia completely messed up my circadian rhythms, but after a while my antidepressants knocked me out. However, the meds weren’t doing much else, but my mood was somewhat better in the nights, so I stayed up late blogging or emailing a friend who lived in another time zone (so midnight for me was afternoon for her), went to sleep around 5.00am. I then slept for ten hours or so. Living with my parents, I also liked being up late so I had the house to myself; unfortunately my parents are also night owls and are often still up at 1.00am or even 2.00am.

    This was not healthy, but I drift back towards it when depressed and when I don’t have structure. I guess I’m naturally a night owl and my mood does get better then, so it’s always tempting to stay up late and do things rather than struggle to do them in the morning, when I can’t even get up unless I have work or something important.

  2. As I am totally blind with no light perception, my circadian rhythm is pretty messy and the fact that I struggle with keeping some decent sleep routine in place doesn’t help. I have an impression after observing my sleep patterns more carefully for a couple of years that it goes in some sort of cycles for me, where the time, in which the times where I am asleep and awake vary, sometimes quite a lot, and also the amount of time I sleep through is different. So I guess I can’t even say exactly if I am a nightowl or a morning bird or whatever, as it is changing every so often. Right now though I’m definitely a nightowl, sleeping on average from about 3 AM to 11. The funny or weird thing that I observed is that it seems like although most blind people quite obviously struggle more or less with melatonin, quite a few of my blind friends and acquaintances who have sleep issues and tried supplementing melatonin say that it didn’t work for them, and even messed up things for them even more. I’ve also tried supplementing melatonin even a couple times, and it just never worked, though I personally didn’t feel any side effects from it.

  3. Very intriguing topic!!

    My “ideal” is to fall asleep at around 1:30 AM and get up at around 11:30 AM. I’ve learned not to sweat a variation of a few hours, because I have drugs that can help righten a slightly off-kilter schedule. (Left to my own devices sans medications… oh geez. My innate circadian rhythms are damaged beyond repair.)

    I feel for you, working third shift. It is really hard, and I can totally relate. I don’t know how I managed to do it when I did, because I sure can’t pull it off any longer. So I admire how you do it!! I think your schedule makes sense given your work hours and sounds workable!!

    With melatonin in pill form, it used to work but then lost its efficacy. I do struggle massively with SAD, so I hope you’ll do some posts about it!!

    1. Meds are definitely useful for keeping a sleep schedule on track. I’m glad my regular meds are sedating enough that I don’t have to add on anything extra.

  4. The good news is that monophasic sleeping (where all the sleep is in one block) isn’t the only natural/healthy sleep pattern. There are a couple of really common biphasic sleep patterns: afternoon siestas plus a late night bedtime in hotter climates, and a pattern of going to sleep shortly after dusk then having a middle of the night waking period followed by a second sleep until morning in areas with long periods of darkness, especially when this is combined with communal sleeping and not much artificial lighting. I can’t find any of the articles I read originally but this one is good:, or google biphasic and multiphasic sleep.

    1. The second pattern is one I fell into quite naturally when I was at camping events with the historic re-enactment group. I’d go to bed quite early and then wake up after a few hours and there would always be people still awake sitting around the fire, so I’d go and join them and chat with them, and then go back to bed when they all did.

    2. Interesting. When I work night shifts I tend to do a morning and an evening sleep, and I’ve never found it as restful as getting the same amount of sleep all in one block. Hard to tell how much of that is night shift related, though.

      1. I imagine there would be lots of other factors at play in how refreshing other sleep patterns are, like whether the main waking period is still within daylight hours, whether you do physically tiring work in the waking period, natural waking vs using an alarm, exposure to the different spectra of artificial lighting and screen based technology vs sunlight and firelight, caffeine and maybe other dietary factors, and also whether the pattern coincided with your natural rhythms – something you pointed out in one of your comments above.

  5. I don’t maintain that rhythm. I work a 4 night shift week and then flip back into day mode the other 3 to spend as much time with family and friends. It was much easier as a young man. Now that I’m over 60 its difficult. You adapt to it. I don’t let myself stress out over it because there are already enough things to disrupt the few hours of sleep I get during the day. I hope to write about the experience of doing that in the future. It has its perks and drawbacks.

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