Thursday, March 11, 2010

Three rounds for time of:

30 Double-unders
25 L-pull-ups
50 pound dumbbells Squat clean, 20 reps

Post time to comments.

How Light Affects Our Sleep,”
courtesy of
Mark’s Daily Apple

Blue Light Computer

Most people are at least cursorily familiar with the concept of the circadian rhythm. For those who aren’t, the circadian rhythm refers to our internal, approximately 24-hour cycle of biochemical, physiological, and behavioral processes. Every living thing, from fungus to bacteria to plant to animal, has a circadian rhythm. External cues called zeitgebers (what a great word, huh?) help synchronize or alter our rhythms; they include temperature, nutrition, meal timing, social interactions pharmacological interventions (medicines, drugs), and, most prominently, the light/dark cycle of the earth.

Yes, light, or the lack thereof, plays an enormous role in the regulation of our cycles, especially our sleep cycle. For millions of years, light was an objective, exogenous measure by which organisms established behavioral patterns, hormonal fluctuations, and sleep cycles. Depending on the seasons, the position of the global axes, and the weather, you could pretty much count on light, bright days and deep, dark nights. Nocturnal hunters and scavengers took the lack of light to mean “eatin’ time,” while other animals (including humans) sought shelter and slumber when night fell. Daylight meant activity and safety (since we could, you know, see everything). Fire, then, wasn’t just about cooking and providing warmth; it also allowed humans a small sliver of daylight’s safety and security at night.

Before I go on, I need to make something clear. My regular readers will have already grasped this concept, but I think it’s a good idea to reiterate it. Though it’s tempting to place us humans on another plane of existence, apart from the mindless flora and fauna that share this world, we are animals. Sure, we’re smarter and more complex than the others, but we’re still subject to these exogenous zeitgebers worming their influential fingers into our subconscious and fiddling with our circadian rhythms. Our tendency to get sleepy when night falls isn’t a cultural relic; we didn’t consciously decide to start sleeping at night because it was too dangerous to be out in the dark. The culture of standard bedtimes arose organically, if you can even call it culture. Does the chirping of birds in the morning reflect cultural tendencies? Is “the early bird gets the worm” a standard axiom in avian academia? No – the early bird’s evolutionary niche decrees that it wake up bright and early in order to get food. It’s basic natural selection, and humans are the same way. We don’t decide to get up early. We get up early because of a complex pattern of environmental cues telling us to get up. Throughout our evolutionary development, handling business during the daytime was simply how we survived. We can’t escape nature.

But boy do we try.

The zeitgeber (can’t get enough of that word) with the biggest impact on our sleep cycle is light. Period. And it’s not just natural light that affects our sleep cycle, but also unnatural, manmade lights. That’s kinda how we operate, actually, as instinctual beings who often misinterpret “unnatural” because, well, our physiology isn’t exactly intelligent. It’s not sentient. It’s purely reactive. Blue light from a 10:00 AM sky, blue light from your computer screen at midnight – it makes no difference to our circadian rhythms. It’s all the same to our bodies, because for millions of years blue light meant daylight, not a late night blog comment section or reruns of The Daily Show. And it’s the blue light specifically that appears to monitor our sleep patterns the most.

Like insulin and inflammation, blue light is integral to our health – in the correct amounts. When we’re exposed to levels of anything in excess (or too little) of what we would have experienced for the bulk of our evolutionary history, problems arise. Blue light regulates our secretion of melatonin, the sleep hormone. Exposed to blue light, we limit the production of melatonin, and we stay alert and awake; in the absence of blue light, melatonin production ramps up, and we get sleepy. This system worked quite well for a long time. Reddish light from fire (our formerly primary source of nighttime illumination) has little to no effect on melatonin production, so sleep wasn’t disrupted when we relied on fire. These days, though, we’re subject to a steady barrage of blue light. During the day, blue light (natural or unnatural) isn’t much of a problem because we’re supposed to be awake, but at night, when we’re “supposed” to be getting ready to sleep, we tend to sit in front of blue light-emanating appliances, and our sleep suffers for it.

(An interesting note on how we respond to blue light. For years, scientists assumed circadian rhythm was set by sight (of light) alone. Person sees sky/LCD screen and the same visual system that allows colored vision determines the hormonal, behavioral, or other physical reactions to the light. It makes sense, but that’s not how it works. It turns out that there exists a second, more dominant system responsible for setting circadian rhythm based on light input. If a person’s sleep cycle depended purely on traditional color vision, we’d expect the blind to universally suffer from disrupted sleep. They do not, however, and this is explained by optical cells that express a photopigment called melanopsin. Unlike the standard rod and cone opsins, melanopsin doesn’t help us see. Instead, it reacts most strongly to blue light, and scientists think it’s the primary regulator of the biological clock and production of melatonin. In otherwise blind patients with intact melanopsin systems, blue light has a strong effect on their sleep cycles.)

Blue light has its place, of course. A British study found that blue light-enhanced white lights in the workplace improved alertness, performance, and even nighttime sleep quality in employees. That’s during the day, though, when blue light exposure is normal and expected. Nighttime exposure to blue light disrupts our sleep hormones. Television, computer screens, even digital clocks with blue numbers – they’re all common sources of late night blue light that can affect our production of melatonin.

Is blue light the only issue? It certainly appears to be the primary driver of circadian rhythm, but it’s not the only one. In a recent study, researchers found that while monochromatic blue light suppressed melatonin production via melanopsin stimulation, polychromatic white light (which includes blue light) stimulated melanopsin equally while suppressing melatonin to an even greater degree. Clearly, it’s not just blue light’s effect on melanopsin affecting our sleep cycles.

Still, blue light is the low-hanging fruit, and there are some simple steps you can take to mitigate its late-night effect on your sleep.

  • Keep electronics usage to a minimum or completely eliminate blue light (alarms, TVs, laptops) after dark.

  • Go to sleep earlier.

  • Use candlelight (read how a fellow MDA reader gave this a try for 30-days).

  • Keep your room as dark as possible and your sleeping quarters pitch black.

  • Install F.lux (totally free) on your computer to cut down on blue light emissions.

  • If you want to try a somewhat extreme experiment you could even wear orange safety glasses at night.

(Thanks to this thread on PaleoHacks for the last two tips.) Also, don’t forget to expose yourself to blue light during the day so that your cycle normalizes – it goes both ways, you know.

Published in: on March 10, 2010 at 8:15 pm  Comments (31)  

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31 CommentsLeave a comment

  1. Wonderful photo. I won’t make it tomorrow a.m. for this wod. I’m going to boot camp as a friend. Playin’ in the mud.

  2. I’m out tomorrow AM as well. Early meeting and this one is definitely longer than 15 minutes.

  3. 22:09 w/ 25# dumbbells for squat cleans. I thought this was going to be quicker but it was tougher than it looked!

  4. Too tired for this WOD this morning. I’ll be in tomorrow.

  5. all M.I.A. (missing in a.m.) folks are cordially invited to attend the noon Power Hour today 😉 after a bit of blue-light exposure, you know you’re gonna want to come play!

  6. Hey, I’m upside down! 🙂

    That article was really interesting and very timely. I’ve been experimenting with not waking up to an alarm and just trusting my body to wake up when I need to. For someone that is notorious for being late, this idea is very counterintuitive, but so far it’s been working as long as I get enough sleep.

    I’ve known people who say they have to have the tv on to go to sleep…so it’s on all night! I wonder if they sleep well. Would not work for me…I need the room to be very dark and quiet. Maybe I’ll try the candlelight idea and see what happens.

  7. 25:01 Got faster as I went through it.

    Did the ALT workout — 3 rounds of:

    30 box hops
    15 pull ups
    15 toes to elbows on bench
    20 dumbell squat cleans with 10 lb dumbells

    Glad that’s over!

  8. Not going to make the power hour, sorry guys. I will have to wait til tomorrow afternoon now.

  9. i caught that stomach bug that’s going around. Hope to be back tomorrow…

    • Oh no! We missed ya.

    • feel better T

  10. Day 2 at Crossfit Copenhagen:
    Since they don’t post their WOD online before hand, don’t follow HQ workouts, and don’t believe in “options” for the WOD, I got duped into doing deadlifts. Busted. I think the last attempt at heavy lifting I made was back in 2008. Oh well, I had already paid for the class and taken the time to get there so I just went with it. Good news was that, again, I was not the worst person in the class! I maxed out at 85kg (didn’t fail, but wasn’t about to try anymore than that). The trainer, who originally thought I was a runner trying out crossfit for the first time, said to me “I never ever would have thought from looking at you when you walked in here that you would be able to deadlift this much weight. You have good form and your core is very strong.”…so I am going to take that as a compliment and wait until 2011 before I do more heavy lifting.
    HOWEVER, Damon should beware! If I do indeed decide to work on it, he might actually have to lace up his running shoes for that half marathon (no, Damon, I have not forgotten about our bet)!!!
    Looking forward to seeing y’all next week.

    • When will people learn not to judge a crossfitter by the way she looks. Glad you showed ’em what you can do. Sorry there were no options. I love options. Options are good.

  11. What’s that blur in the gym? Is it a bird, a plane? No, it’s KaZaM (Kelly and Zeke and Michael) flying through that CTB pull up, box jump WOD! Nice work guys.

    Today’s WOD Rx 34:54.
    My L-pulls leave a lot to be desired. And why is it that I always have to learn the same lessons over and over. Form makes a BIG difference on squat cleans (keep DBs close to body, triple extension, jump it up…) Thanks for the pointers Michael.

    • You made me laugh. Thanks. 😀

      L-Pulls, huh? You are something else.

    • RX though!!! Get it!!! nice work

      • Congrats Sheryl for being the only person that has (and prolly will) go Rx on this one…I know 50# is more than I have done, and 35# is rough!! Gr8 job Lady 🙂

        Mike, Kelly and Zeke,
        Amazing performance at lunch today!! You all blew away the VA Firebreathers…and FYI, Mama Bear was very impressed with yall’s times!

        For me, I’m about to lift (back squats), but I just finished “Annie” in record time…gr8 day!

        Double Unders
        AbMat Sit Ups

        7:04 (40+ sec PR)

        • D, with that many ab-mat situps clearly your back is BACK in force! nice work…and everyone please note that he didn’t even look tired or anything at 4:25!

    • Sheryl, I must say that, upon reflection, I think I’m even more impressed by your consistently positive, engaged attitude than by your amazing feats of strength during the Power Hours! So often you’re the only one doing the WOD yet you continue to learn and work Crazy hard to the end! Inspirational.

  12. Did the Alexandria VA wod with Michael & Kelly today. We had Box Squats (did I say that right?) Worked our way up from 176lbs to 262lbs.

    After, we did a quick 5 rounds of:
    10 Chest to Bar Pullups
    15 24″ Box Hops

    Time: 3:35

    Kelly and Michael, it was a pleasure. Kelly, you keep me on my toes with the met-cons!!

    • good stuff today, lotta fun!

      • …nothing like chasing two of the quickest, most efficient body-weight dudes in the Southeast to make one wish he weighed 40# less 😉 thanks for letting draft off you guys today!! LOL

        • *insert “me” between letting & draft above (duh)*

  13. Felt really good about my workout today. It was pretty strenuous but I got to work on some strengths and some weaknesses.
    7 sets of:
    1 strict chin up
    2 L pull-ups
    3 butterfly kip pull up
    4 chin up break vertical line
    5 chest to bar pull ups
    rest 2 min in between each set.
    Time for each set (including 2 min rest in between): 1:09/4:06/7:09/10:34/13:56/17:18/21:14

    For total reps: 30 sec of double-unders followed by 30 sec of rest for 10 rounds.
    8,2,10,4,5,3,8,8,7,5=Total of 60

  14. 3 rounds:
    30 Double-unders
    25 L-pull-ups
    35 pound dumbbells Squat clean, 20 reps

    Double-unders continue to be a weak point for me. L-pulls were relatively easy. DBSCs were difficult but manageable. Wish I had brought my weightlifting shoes.

    • Oh, yeah: time was 25:16

  15. 3 rounds:

    15 box hop
    15 pull-ups
    15 toes to bar
    20 pound dumbbells squat clean, 20 reps


  16. 3 rounds:
    30 DUs
    25 L pull-ups
    20 dumbell squat cleans (20#)


  17. 3 rounds:
    30 DUs, 15 pull ups (red), 15 knees to elbows supine, 20 DBSC 10#


  18. After I read “Lights out” Sleep Sugar and Survival” I completely changed my sleeping habits and light exposure. I feel SO much better.

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