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Sleep! (RuLu presentation)


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Sleep: we all do it, and yet somehow it's hard (as most of us can attest every morning). It's also really relevant: as thinkers, creators, and problem solvers, anything that makes our brains less effective matters. Missed sleep makes a difference -- even two fewer hours a night quickly produce measurable cognitive impairment. Things get more interesting when we look at why it's so hard: our sleep cycles are determined by our internal clocks, which often put us in conflict with society's timetables, leaving many of us in a state of "social jet lag", as if we'd been traveling a timezone or more every day. That's not how any of us want to code (or live), I think, and by understanding how and why so many of us are constantly tired, we can start to make things better.

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Sleep! (RuLu presentation)

  1. 1. 💤 Sleep!Alex Koppel - @arsduo
  2. 2. Why talk about sleep?• Our job is to solve problems• Sleep is tied to how well we can think [4]
  3. 3. AlsoWe have a macho culture about sleep
  4. 4. How do we get themost out of ourselves?
  5. 5. Part ILess Sleep, No Sleep and what happens to you
  6. 6. Sleep Deprivation Just stay up till its done
  7. 7. sleep(0)• Sleep deprivation hurts your ability to think • “This deactivation is greatest in those brain areas sustaining higher cognitive performance and situational awareness.”• 25% mental decline / 24 hours awake Source: [3]
  8. 8. Just how bad?~66% performance loss after 3 days Source: [3]
  9. 9. Not sleeping is a bad idea (Not a surprise)
  10. 10. Sleep Restriction"Just one more episode, then Ill sleep"
  11. 11. Sleep Needs• Most people need between 7 & 8.5 hr sleep [4, 6]• What happens when you get less?• Is it similar to sleep deprivation?
  12. 12. def chronic sleep restriction• Getting reduced sleep over repeated nights • Like an estimated 20%+ of Americans [10]• How many of us sleep too little?
  13. 13. QuestionIs sleeping 6 hours a night reasonable?
  14. 14. Less sleep, less brain• Sleep restriction reduces brain function • Surprise!• Cumulative effects over time• Proportional to how much sleep you skip
  15. 15. Responsiveness Test 0 hours sleep: errors rise quickly y axis: failures to respond to test prompt in time 1 tick = 2 days Source: [1]
  16. 16. Responsiveness Test 8 hours/night: effectively normal 1 tick = 2 days Source: [1]
  17. 17. Responsiveness Test 4 hours a night: in just one week, you’re in sleep-deprived territory 1 tick = 2 days Source: [1]
  18. 18. Responsiveness Test 6 hours a night: in the second week, you’re sunk 1 tick = 2 days Source: [1]
  19. 19. Just to be clear Your brain will hit sleep-deprived territory. This is bad. 1 tick = 2 days Source: [1]
  20. 20. Is sleeping 6 hours a night reasonable now?
  21. 21. Caveats• Sleep needs vary between individuals • What you’ll see are average numbers • But most of us are average sleepers!• Studies vary, but only so much
  22. 22. Take the weekend off• OK, but can’t you just sleep it off over the weekend?
  23. 23. Apparently not• The brain physiologically adapts to less sleep [2, 4, 9] • These last for at least several days• Recovery sleep is physically different [4]
  24. 24. Incomplete recovery Baseline (min) Source: [2]
  25. 25. Part IIWhys and Wherefores Why its so hard to get enough sleep
  26. 26. Late to bed, early to rise• Sleep restriction is a common problem• Why is getting enough sleep so hard?• What can we do about that?
  27. 27. Chronotypes Our sleep patterns
  28. 28. Sleep pattern spreadWakeup time for 7 8 AM 10 AM hours sleep: Source: [6] p. 13
  29. 29. Alternately putOver 50% of the population wakes btw 8 and 11 AM Only ~33% naturally wake up before 8 AM Source: [6] p. 13
  30. 30. Yet• Much of society starts up between 8 and 9• What happens to all of us whose bodies want to wake later?
  31. 31. Social Jet Lag• When society time != body time• Expressed through sleep deprivation• Like traveling by plane every day • Over 40% of Central Europeans off by 2+ hours Source: [6] p. 149
  32. 32. Objection• But, but, surely people can adjust as needed? • Are we all just lazy bums?
  33. 33. Body Clocks The Art of Entrainment
  34. 34. Here’s where it gets complicated (and interesting)
  35. 35. Internal Clocks• All humans (organisms) have internal clocks• Few run exactly 24 hours per cycle • On average slightly longer [11]• Our bodies use light to sync with the world Source: [6] p. 1, 118-127
  36. 36. Internal DayWhen you wake up When youre asleep (hopefully) Source: [6] p.121
  37. 37. Internal DayWhen you wake up When youre asleep (hopefully) Source: [6] p.121
  38. 38. Entrainment• Our bodies use light to adjust the internal day• Light in inner morning shortens the day• Light in inner evening lengthens it• The body mixes both to get the right adjustment Source: [6] p.117-128
  39. 39. Problem• Your day is too long • You have to emphasize compression • More morning than evening• How?
  40. 40. Solution!• Wake later • Your inner evening happens in the dark!
  41. 41. And• If most people have a longer clock, wed expect most people to wake later• And thats what we saw earlier!
  42. 42. Implication• Sleep cycles are determined by biology• We cant control / change this• Have to accept people are as they are
  43. 43. More proofWaking times among a homogeneous population in 1 time zone are controlled by the sunrise Source: [6] p.158
  44. 44. Part III SundryA whirlwind tour of other topics
  45. 45. Stuff I don’t have time to cover*• Caffeine• Napping• Polyphasic sleep / split sleep• Urban environments / the Great Outdoors• Core sleep• Organizing your day to your daily rhythms• Drinking water to stay awake * or haven’t yet researched :D
  46. 46. Not to speak of...• Lots of other stuff affect both sleep quality and thinking • Alcohol, other drugs • Exercise • Stress • Diet • Working environment
  47. 47. Part IVConclusionWake up, its almost over
  48. 48. Consequences• When peoples work aligns with their cycles, they perform better Source: [6] p.112
  49. 49. In practice• Respect your own biology• Get enough sleep!• Encourage your team to sleep • Flexible start times
  50. 50. Thanks! @arsduo @6Wunderkinder
  51. 51. Eurucamp 2012
  52. 52. AppendixSources and other material
  53. 53. Science is fun• “Some evidence suggests...” • Hard conclusions are hard• Explanations, like this, can be preliminary• Moar studies! • But the basics presented here are solid
  54. 54. A possible mechanism• Effects of sleep restriction and deprivation postulated to share a common trigger [1]• Cumulative excess hours awake • How much longer you’re up in a given period than you should have been• Deprivation effects likely =~ restriction effects (in proportion)• Not the only proposed theory Source: [1]
  55. 55. PVT• Psychomotor vigilance test• Subjects respond to a visual stimulus• Measures attention and response time • Also lapses (response > 500ms) Source: [12]
  56. 56. Do these results matter?• PVT (the test) measures both reaction time and sustained attention• Does it apply to general brain function? • What’s it gotta do with coding?
  57. 57. Other results similarDigit substitution, addition/subtraction Source: [1]
  58. 58. Sources1. Van Dongen, H. P. a, Maislin, G., Mullington, J. M., & Dinges, D. F. (2003). The cumulative cost of additional wakefulness: dose-response effects on neurobehavioral functions and sleep physiology from chronic sleep restriction and total sleep deprivation. Sleep, 26(2), 117-26. Retrieved from Source: Van Dongen, etc., UPenn Study, 2003 [1]2. Belenky, G., Wesensten, N. J., Thorne, D. R., Thomas, M. L., Sing, H. C., Redmond, D. P., Russo, M. B., et al. (2003). Patterns of performance degradation and restoration during sleep restriction and subsequent recovery: a sleep dose- response study. Journal of Sleep Research, 12(1), 1-12. Retrieved from Belenky, G. (1997). Sleep , Sleep Deprivation , and Human Performance in Continuous Operations, 1-13. Retrieved from Alhola, P., & Polo-Kantola, P. (2007). Sleep deprivation: Impact on cognitive performance. Neuropsychiatric Disease and Treatment, 3(5), 553-567. Dove Medical Press. Retrieved from artid=2849789&tool=pmcentrez&rendertype=abstract5. Robinson, E. (2005). Why Crunch Mode Doesn’t Work: 6 Lessons. IGDA Retrieved Feb, 1-6. Retrieved from http:// Roenneberg, Till. Internal Time: Chronotypes, Social Jet Lag, and Why Youre so Tired. Cambridge, MA: Harvard UP, 2012. Print.7. Popova, M. (2012). Internal Time : The Science of Chronotypes , Social Jet Lag , and Why You’re So Tired. Retrieved from Roenneberg, T., Daan, S., & Merrow, M. (2003). The Art of Entrainment, 18(3). doi:10.1177/0748730403253393
  59. 59. 9. Sources 2 Fackelmann, K. (2007). Study: Sleep deficit may be impossible to make up. USA Today. Retrieved from http:// Hublin C, Kaprio J, Partinen M, Koskenvuo M. (2001) Insufficient sleep: a population-based study in adults. Sleep, 24: 392– 400 cited in Wikipedia, replace w other data11. Toh, K. L., Med, M. I., Uk, M., & Genet, H. (n.d.). Basic Science Review on Circadian Rhythm Biology and Circadian Sleep Disorders, 662-668.12. Psychomotor vigilance task. (2012, June 11). In Wikipedia, The Free Encyclopedia. Retrieved 10:24, June 22, 2012, from