Link to original: http://sphynxcatvp.nocturna.org/health/sc-circadian.html
Mythology describes vampires as being nocturnal, either by preference or necessity. It's pretty common among the vampire community for people to report being nocturnal by preference, but the assumption is often made that this is a symptom of vampirism - and thus unusual outside of the community - when it's more common outside the community as well than many people realize.
What is a circadian rhythm?
"Circadian" is a term derived from Latin, and means "about a day." The circadian rhythm, therefore, is a day/night collection of physiological cycles - wake/sleep cycle, appetite, hormone levels, alertness, body temperature, etc. - that occur over a 24 hour period, and governed by the body's internal clock.
Circadian disorders, therefore, are conditions in which your wake/sleep cycle is "out of whack" compared to the stereotypical mundane norm. Sleep disorders can occur with shift work, jet lag, delayed or advanced sleep-phase syndromes, and other things. This will lead to insomnia during attempted sleep times, and excessive sleepiness during attempted waking times (such as being at work.)
What is a normal circadian rhythm?
Medically, the circadian rhythm is recognized as being normal under the following circumstances:
- Can naturally wake in time for what they need to do in the morning
- Can naturally go to sleep at night in time to get enough sleep for morning
- Wake/sleep at the same time every day if they want to
- Natural adaptation (shift of about 1 hour per day) of wake/sleep cycle on change to a new schedule.
Note that this definition does not specify the specific hours for waking/sleeping.
Many doctors, however, consider a normal circadian rhythm - when you're NOT working a late or overnight job - to be only a schedule where you're awake during the day and asleep at night, regardless of any other factors. Why yes, that IS a pain in the ass when trying to explain it to them that you're "Just Not A Day Person ThankYouVeryMuch..."
How is a circadian rhythm disorder diagnosed?
Generally, you will be advised to keep a sleep log, detailing your wake/sleep times, anything you're doing before bed, any medications and such that you're on - and when you take it relative to when you go to bed, etc. Then the medical professional can discuss with you the implications of anything in the logs you've kept, and bring up other things that may affect your wake/sleep schedule that you may not have thought of.
Once logs and basic treatment methods are ruled out, a sleep study can be done, which rules in or out things like sleep apnea, and imaging studies if a neurological or other health issue suspected.
How does it get messed up?
Two main external causes
- Jet lag
- Shift Work Sleep Disorder
Four main internal causes
- Delayed Sleep Phase Syndrome (DSPS)
- Advanced Sleep Phase Syndrome (ASPS)
- Irregular Sleep-Wake pattern
- Non-24-hour Sleep Syndrome (Non-24)
- Artificial sweeteners (if it's one of the ways your body doesn't react well to them)
- Chronic pain (because it's hard to sleep through the pain)
- Cancer (again, because it's hard to sleep through the pain)
- Medication Side Effects (sleep aids, antihistamines, timing of thyroid medications, etc.)
- Sleep apnea (waking up so much means sleep is not good)
- Stress / anxiety
- and etc...
Jet lag happens when people cross multiple time zones and their body hasn't adapted to the day/night cycle of the new timezone yet. This usually takes at least a day or two of adjustment, especially for major time zone shifts (going from the USA to Europe, for example.)
Shift work - especially rotating shifts on a short (weekly) schedule - are especially prone to screwing up your sleep schedules. It's easy enough (for most) to adapt to an evening or overnight work schedule provided it's the SAME schedule for at least a few weeks. Because it takes a few days to adapt to a new schedule, changing every week will constantly throw people's sleep schedules off - they'll be just getting used to the new schedule when it changes again.
Delayed and Advanced sleep syndromes cause either a much later or much earlier timing of the sleep/wake cycle. This is only an issue if you're working on a shift that goes against that timing, or you have family that's on a different wake/sleep cycle timeframe.
Non-24 sleep cycles are - as the name implies - not on a 24 hour schedule. Typically the schedule is longer than 24 hours, sometimes as long as 26 hours. This primarily affects people who are totally blind since their bodies don't react to light, but in rare cases may affect sighted individuals as well, due to a possible neurological cause.
Irregular sleep-wake pattern presents as sleeping or waking at unusual times (such as waking several times in a night, or taking several naps during the day), and often multiple times throughout a 24hr period, on a regular basis.
Anemia and sleep apnea interefere with sleep by preventing quality sleep - with anemia you tend to be tired all the damn time if it's severe enough, and with sleep apnea, your body keeps waking up roughly about every couple hours.
Medications can have all kinds of side effects, both due to the nature of the drugs, and sometimes (as in the case of thyroid medications) due to the timing of when you take it versus when you go to bed.
Chronic pain and cancer both cause sleep issues due to the amount of pain - with cancer, the pain is usually 24/7 without any letup. For those who don't understand why cancer causes pain, you should understand that most cancers amount to uncontrolled growth - tumors - in various soft tissues and bones. This means that there is extra material trying to squeeze into a space that was already full. THAT is why cancer pain is a steadily increasing 24/7, while most other pain is not.
What are some ways to readjust it?
Primarily these methods will attempt to gear your subconscious towards thinking of the targeted sleep time as "bedtime" rather than a time for more brain activity. These include:
- Behavior changes - avoid naps, caffeine and other stimulants before bed./li>
- Avoid the bed for anything besides sleep and sex
- Bright light therapy to advance or delay the sleep cycle
- Medications to promote sleep or prolong waking periods
- Melatonin / Niacin
- Progressively advance/delay sleep cycles by 1-2 hrs each day ("Chronotherapy")
(Circadian rhythm disorders can affect whether you have insomnia compared to your desired/needed wake-sleep preferences; because of that, you can find additional tips and details in my article, Insomnia Basics.)
If you're under 18, and still living with parents/guardians, sorry, there's not much I can offer to help - you're just out of luck until you can move out on your own. If you're going to school/university/college, you're kinda stuck with the times they offer the classes you need.
The best thing I can suggest is to do what you can to minimize any change in schedules between workdays and non-workdays. Yes, this DOES mean getting up at the same time on the weekend as you do during the week. All. The. Time. No, it's not fun - but if you can keep your schedule the same, day after day, then you will eventually have less problems getting to sleep when you need to, and getting up when you need to.
As an adult, having a circadian rhythm that is not "normal" is NOT a problem UNLESS you have a job or other obligations that require you to be awake when your body says you should be sleeping. As an adult, it's easier to rearrange your life to suit YOU - even if it means you work nights instead of days. :)
- About.com: What is a Circadian Rhythm?
- eMedicine: Sleeplessness and Circadian Rhythm Disorder
- Journal of Sleep Research: Delayed Sleep Phase Syndrome
- Journal Sleep: ...Circadian Clock Gene Per3 Linked to DSPS... (PDF)
- Harvard Med: Healthy Sleep Glossary
- Journal of Circadian Rhythms
- NIAAA: Overview of Circadian Rhythms
- NIGMS: Circadian Rhythm Fact Sheet
- WebMD: Circadian Rhythm Disorder