Current location:	at work, on the night shift
Current mood:	amused
Current music:	"The Night Shift"
Entry tags:	24-hour, brain_hacking, circadian_rhythm, melatonin, night_shift, serotonin, sleep

The Night Shift
There was a "night shifts cause cancer" news meme being pushed today.

When I first told my mother that I was going to be working the night shift, babysitting computers as part of a 24x7 department, her reaction was "oh, you're one of THOSE types now, are you?" Her experience with the night shift was when she was a nurse, before I was born. They had it much worse than I do. Sometimes they'd be on days, and sometimes on nights. My work schedule is all nights, completely predictable and compact: three or four 12-hour night shifts in a row, then the rest of the week off. There's not much I can get done between shifts, but the rest of the week is great for traveling.


A recent NY Times article quoted a night auditor for a hotel as saying

If you had told me when I was a teenager that I would be working through the night for 30 years, I would have laughed at you. But I love my job because nighttime is generally quiet and peaceful, and I’m the one in charge. At this point, I am 48 years old and I can’t see myself being happy doing anything else.

The night shift is in my blood.

I understand, although I don't plan on doing this forever. It's so much quieter here at night. No annoying users calling up with trivial problems like during the day. Sometimes there's a serious problem, and I'm paid to handle it efficiently. Between emergencies, there's always *something* I could be doing, but usually nothing terribly urgent. It's just me and the computers, a group mailbox full of email to answer, a pile of service requests to handle, problem tickets to close out, and a turnover note to update to pass along information to the next shift. Fairly routine stuff normally, but there are a few chances per month to Google something new about Unix system administration to solve a problem. There are a lot worse ways to pay the bills.

After nearly four years of this, I feel like I've completely adjusted, as much as one can. The thing I found strangest about it in the beginning was the back-and-forth with our counterparts on the day shift. I come in as they leave, and just twelve hours later, we switch. With an hour for commuting, a half-hour for turnover, and a best-case scenario of eight hours of sleep, that would leave us 2.5 hours to cook food, shower, dress, listen to voice mail, and run errands. Needless to say, I don't get eight hours in-between shifts unless I'm in extreme sleep deficit.

During an unemployment spell, before I'd ever worked nights but with no outside pressure to stick to days, I would see my sleep cycle roll over completely every few weeks because I wasn't living on a 24-hour day. I was doing stuff when inspired to, and sleeping when I needed to. That was the first time you'd see me waking up naturally at dawn, but then the cycle would continue shifting up to late afternoon and then flip back. I love the idea of a 28-hour day, six-day week--some day I'll probably try it.

Now, I do a "12-hour timezone shift" twice a week, once in each direction. On Wednesdays, I normally stay up all day before my first 7pm to 7am shift of the week. I don't necessarily sleep extra on Wednesday mornings. Often on Wednesdays (especially in the last year) I'm driving home from wherever I've just spent the last few days. I switch over to sleeping days on Thursday and Friday before those night shifts. If I can get 6 hours of sleep those days, I'm doing well, but sometimes I get sucked into the computer or have some event to attend and get less sleep than I should. I don't break up my sleep blocks between shifts, though. If I wake up before I need to--as long as I've gotten at least four hours and feel awake, I'll stay up.

Every other week, I work Saturday night as well, so I'm done either Saturday morning or Sunday morning at 7am. I may end up napping a bit after that last shift, waking up for a while from late afternoon to evening, and then getting a good night's sleep that night--but just as often, I stay up all day after that last shift and then start a 16- to 24-hour catch-up period, with maybe six hours of waking time in there before I return to bed to finish repaying the sleep debt.

Serotonin and Melatonin

So, there's my night-shift experience...now about the "carcinogenic effect" of working the night shift. Just a few months ago, a Swedish study said exactly the opposite, but this new WHO study finds a connection, speculating that it's due to decreased melatonin production. Serotonin, a major neurotransmitter in our brain, is a precursor to melatonin. Melatonin lowers alertness and increases the desire for sleep. Serotonin is synthesized in the body from tryptophan. Some modern anti-depressants, SSRIs, work by inhibiting serotonin re-uptake, leaving more in your bloodstream to keep you happy and unstressed.

I've known about melatonin supplements for a long time, thanks to Dana Beal. He also promotes Ibogaine, which is an analogue of melatonin and stimulates very intense "waking dreams." That's a very powerful drug, though. For everyday use, some of the lucid dreaming crowd are interested in melatonin, because decreased serotonin leads to less dreaming, and the melatonin helps restore dreaming. Taking melatonin supplements helps preserve serotonin in the bloodstream by removing the need to use it to make melatonin (in the pineal gland). Which means that keeping up your tryptomine levels is even more important, because otherwise there won't be any serotonin there in the first place.

How helpful that we cook up 30 pound turkeys (lots of leftovers) a month before the darkest part of the year! Brown rice, dairy and peanuts are also good sources of tryptophan, they say. That article also has information about the tryptophan supplement ban, which seems to have been lifted. Shrimp and meats have more tryptophan than vegetarian sources, but the other amino acids in a high-protein meal interfere with tryptophan absorption, so it may be better to eat carbs with tryptophan.

I sometime notice the effect on my dreams when I take a melatonin pill before sleeping. I feel like I'm getting a deeper sleep when I take a melatonin, but I don't take it regularly. After reading the articles about these studies and doing some fact-checking to write this post (I had thought that melatonin was the precursor to serotonin rather than the other way around), I think I should start either taking melatonin or boosting my tryptophan intake somehow. An article from earlier this month on Circadian disorders suggests that "Melatonin administered at the appropriate time reduces symptoms of jet lag and improves sleep following travel across multiple time zones." and "Melatonin promotes daytime sleep among night shift workers. Modafinil enhances alertness during the night shift for a shift work sleep disorder." (I just read up on Modafinil a bit. Sounds like fun, but I don't really need it.)

Sunshine and Daydreams

Anyway, the idea behind the recent studies is that being exposed to (blue) light while you are sleeping leads to decreased melatonin production.

The presence or absence of light has a strong effect on your sleep cycle, but I can attest that even in the middle of a building, not in sight of any windows, the 2:30am to 5am period is still the toughest, and I start to wake up again a bit after 5 am. This study confirms an independent mechanism: the persistence of normal cycling during constant darkness depends on a protein (called PDF) secreted by the ventral lateral cells.

For those who have a hard time getting to sleep when they get home, wear sunglasses on the way home from the night shift, which tricks your body into thinking it's night, and then make sure your bedroom is dark, so you can make melatonin and go into deep sleep cycles, which are necessary for keeping your sanity and for processing things learned during while awake.
You could also wear blue-blocking glasses to be able to fall asleep or get a blue light to stay awake.

There is debate about whether covering your eyes is sufficient, or whether light on the back of your knees matters. (Knees were debunked.) I don't actually keep my bedroom pitch-black, but there's certainly no direct light, and barely any blue light. Sometimes I keep NPR on in the next room during the day, so it's not always quiet, either.

I like to joke that I have no circadian rhythm anymore. Not quite true, but I have good control over alertness when I need to. I can stay awake all night without caffeine if I'm not too sleep-deprived, but I have an unfortunate addiction to Mt. Dew Code Red that I justify because I work the night shift. (I quit caffeinated sodas for three weeks in October! Once I gave them up for about two years, but then I started the night job.) The greater my sleep debt, the harder it is to pull myself out of bed, but the prospect of going right into the shower helps.

I was always a bit of an insomniac, in that there's so many more interesting things for me to do instead of sleep. It's hard to drag myself to bed until I'm really exhausted. Life is so short, why waste it sleeping! But then once I do go to bed, I can fall asleep nearly immediately. I love the coziness of blankets, lots of pillows and a warm cat, and I can stay there quite a while if there isn't something I *have* to do.

If you don't sleep

Our bodies are controlled by an internal daily body clock, situated in the suprachiasmatic nucleus (SCN) in the hypothalamus. The SCN spontaneously generates the circadian rhythms that regulate many physiological and behavioural processes in our bodies, such as temperature control, hormone production, alertness and sleep.

from: Working the Night Shift (PDF) a guide for doctors in England

I do notice impaired thermoregulation when I'm overtired. Other symptoms when I miss significant sleep over many days include irritation under my eyelids and (after *very* long stretches of insufficient sleep) a white haze obscuring some of my peripheral vision. Eventually, my joints feel weak and loose, as if I no longer have the energy to keep my body together. That's when I know I *have* to collapse and catch up on sleep. Food even tastes better when you're not serotonin-depleted. Serotonin depletion will cause carb craving.

Staying awake

Jumping jacks at work. Singing in the car. Those work the best for me. Keeping the car window open doesn't work well enough. Hitting my leg repeatedly like Dad did on late night car trips just hurts too much. I'd rather get a sore throat singing along to Bob Dylan or Amy Winehouse, plus that works better for me.

I have iTunes configured to give me a nearly-constant news stream (a smartlist picking up fresh news summaries hourly from multiple sources). Mental stimulation matters as much, if not more, than physical. Like the hotel auditor, I surf the web a bit to stay awake. In the last year, I've started chatting with friends sometimes who are also up late.

You have to manage your sugar and caffeine intake carefully to make it through the night. Back in college, I was just an amateur. I did a few all nighters, but not regularly, and I'd end up getting sick for a week if I pushed it too far. Now I know that I shouldn't have caffeine before 11pm if I want to make it through the whole night awake, nor can I get on the sugar-fueled roller coaster, no matter how tempting the vending machine seems. Once you've overdone it with caffeine or sugar for the night, you might as well get a nap, because it won't matter how much more caffeine you drink until your system clears out a bit. You can last a long time on 1.5-hour naps. That's the length of going into a REM cycle and coming back out, they say, so your sleep should be in increments of 1.5 hours.

We keep the lights rather low in the office. I eat a full meal right when I come into the office. Sometimes that's my only meal of the day, in fact. That's too early to put me to sleep, as long as it's not too carb-heavy. You have to avoid an energy spike, because you can't recover from an energy crash too well without a nap or some sunlight.

So, does the night shift really cause cancer?

The latest articles don't do the subject justice. If you're chronically serotonin-deprived, that isn't good, we know that. Can people with adequate tryptophan, serotonin, and melatonin levels avoid the negative consequences found in this study? I would assume so, based on common sense, but let's see some data! Does this study tell us anything that this one, suggesting a fundamental connection among circadian timing, cell cycle progress, and potentially the origins of some cancers didn't?

Melatonin supplements are probably a good idea for nightshift workers and others with depleted serotonin. I would recommend them for anyone who's having problems getting deep sleep, as long as they can set aside time to sleep. Take them an hour before bed. Dana recomends letting the pill dissolve on the gumline for more rapid absorbtion. Why didn't the articles mention melatonin supplements at all?

Sorry if this is a bit rambling. I'll look at it again after I've had some sleep. ;-)

An Amusing Link:
Livelyhood: Nightshift from PBS