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Comment by splittingTimes | Hacker News Reader

What does "disruption of circadian rhythm" really mean in layman's terms?

"influence our biological clock, including night shift work, extended light exposure, changes in sleep/wake cycles and altered feeding behavior,"

Is it anything that deviates from going to sleep when the sun sinks and sleeping through till you naturally wake up when the sun rises?

What about those:

Waking up at night because you have to pee?

Waking up early because you got something on your mind (like work related problems that need solving)

Going to bed late because you addictively browse HN?

Jet lag after travels?

Not taking an after lunch nap when I feel like it?

Needing to be wakened by an alarm?

Generally bad or not enough sleep?

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I'll take a layman's crack...

>Waking up at night because you have to pee?

You may want to not drink large amounts of liquid before going to bed, altering your liquid consumption times/schedule could resolve this.

>Waking up early because you got something on your mind (like work related problems that need solving)

Stress is known to generally be bad for health and well-being, there are animals can outright die from too much stress.

>Going to bed late because you addictively browse HN?

Stick to a better schedule.

>Jet lag after travels?

Don't travel too much if you can help it.

>Not taking an after lunch nap when I feel like it?

This may have to do with an unhealthy diet

>Needing to be wakened by an alarm?

Personally I've noticed that after using an alarm for a month or so, I start to naturally wake up just before the alarm is set to go off.

>Generally bad or not enough sleep?

Definitely an issue, if you cannot find a solution on your own, you may want to see a specialist.

> You may want to not drink large amounts of liquid before going to bed, altering your liquid consumption times/schedule could resolve this.

Sleep apnea causes nocturia, so that might not be a solution.

I always wonder about these types of studies too. I have diagnosed delayed sleep phase disorder, secondary to adhd. I sleep odd hours compared to the norm - approximately 3am to 10am. However, my schedule (while odd) is completely stable. I go to bed when I feel tired and I wake up feeling refreshed.

Does the fact that my natural sleep habits are so off-the-bell-curve put me in the "disrupted circadian rhythm" group or not? I never feel sleep deprived. And I've been told by specialists that trying to force myself to sleep a normal schedule could put me at a significantly increased risk of dementia, alzheimers, stroke, heart attack, and more.

So the thought that I might still be doing myself harm sucks.

From what I've read, the damage comes from jet lag and shifting schedules. If you have a stable sleep schedule and are exposed to light and noise and so on in the same way that regular people are, then your body won't (can't) know the difference.

Your body has a lot of processes that run on a 24-24.5 hour clock, such as metabolism, melatonin and temperature, which are mostly synchronized and coordinated by bright light exposure. You're designed to sleep during part of that 24 hour cycle, and be awake during another part.

Large disruptions are worse than small ones. Waking up 1 hour earlier than normal occasionally is not a large disruption. Jet lag because you woke up 5 hours earlier would be a big disruption.

What does a big disruption look like in terms of measurements? All of the many processes than normally oscillate together in phase go out of phase.

I'm no expert in this stuff, but if you want to read about it, search for "chronobiology".

> Is it anything that deviates from going to sleep when the sun sinks and sleeping through till you naturally wake up when the sun rises?

And how does it affect people living close to the poles, where the sun basically doesn't set for 3 months in the summer and doesn't rise for 3 months in the winter. (Scandinavia, Canada, etc)

Free-running sleep disorder in the extreme case of no sun and no concerted effort to entrain to sufficiently bright artificial light.

"Probably the best study to illustrate the effects of an unstructured life during the Antarctic winter is that of four Greenpeace volunteers over-wintering at Cape Evans Base 77°38′S in 1990 (Kennaway & Van Dorp, 1991). For the entire period of sundown (sun below the horizon for 126 d), all four (three men and one woman) showed free-running rhythms of all the variables studied: sleep, aMT6s, electrolytes, and cortisol. Each person free-ran with their own period initially, although two (a man and a woman) subsequently free-ran with the same period. With the return of the sun, all four resynchronized to the 24-h day."

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3793275/

Think of a heatmap of your hours awake over the past 6 months. How many of these things like waking up to pee actually make a difference? There's your answer.

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