I gave this 5-minute lightning talk about sleep at Euruko 2012 in Amsterdam. In the presentation, I show the effects of sleep deprivation (no sleep) and sleep restriction (less sleep), which are important and often undervalued topics for developers and other professionals whose jobs depend on creative thinking (and for everyone else, too!). The presentation also touches on several other interesting sleep-related topics that I hope to expand on in a longer version. My sources are listed on the last slide -- check them out (they're interesting). If you know any additional interesting books or articles on sleep, any anecdotes about changes to your sleeping schedule, or find any errors in my presentation, let me know! I'd love to hear your thoughts.

1. Less Sleep, No Sleep,
and What Happens to You
Alex Koppel - @arsduo

2. Introduction

3. Why talk about sleep?
• Our job is to solve problems
• Sleep controls how well we think [4]
• We have a macho culture about sleep

4. How do we get the
most out of ourselves?

5. 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
• Probably no surprise to any of us
Source: [3]

6. Sleep Restriction
Or, less sleep, less brain

7. Sleep Needs
• Most people need 7-8.5 hours sleep [4, 6]
• Many don't get it
• How many of us got a full night of sleep?
• What happens then?

8. Less sleep, less brain
• Sleep restriction reduces brain function
• Surprise!
• Proportional to how much sleep you skip
• Cumulative effects over time

9. Question
• Is sleeping 6 hours a night reasonable?

10. Responsiveness Test
0 hours sleep:
errors rise quickly
1 tick = 2 days
Source: [1]

11. Responsiveness Test
8 hours/night:
effectively normal
1 tick = 2 days
Source: [1]

12. Responsiveness Test
4 hours a night:
in just one week,
you’re in
sleep-deprived
territory
1 tick = 2 days
Source: [1]

13. Responsiveness Test
6 hours a night:
in the second week,
you’re sunk
1 tick = 2 days
Source: [1]

14. Same test, similar results
Source: [2]

15. What's it gotta do w/ coding?
• Higher functions are affected too
• More complex tests show similar trends
• The normal learning process doesn’t happen
Source: [1]

16. Question redux
• Does 6 hours a night still seem reasonable?

17. Other Topics
A too-quick overview

18. Recovery Sleep
• Can't just recover over the weekend
• Brain seems to responds to less sleep
w/ long-term physiological adaptions
[2, 4]
• One study shows below baseline after 3 nights
• Recovery sleep is physically different
[4]

19. Chronotypes
• Natural sleep rhythms vary significantly
• "Social jet lag": always waking too early
• Usually to meet society's timetable
Source: [6]

20. Chronotype Spread
Only ~33% naturally wake up before 8 AM!
~45% wake up between 8 AM and 9:30 AM
Source: [6]

21. Consequences
• Are we handicapping ourselves?
• Entrepreneurs tend to later sleep cycles [7]
• When people's work aligns with their cycles,
they perform better [6]
• Valid limits: in-person time is valuable too

22. Conclusion

23. What does this mean in
practice?
• No crunch mode
• Get enough sleep!
• Encourage your team to sleep

24. Be like him

25. Thanks!
@arsduo
@6Wunderkinder
http://dev.6wunderkinder.com

26. Appendix

27. Caveats
• Sleep needs vary between individuals
• These are average numbers
• But most of us are average sleepers!
• Studies vary, but only so much
• Many other factors affect sleep & the brain

28. PVT
• Psychomotor vigilance test
• Measures two things:
• response time (ms)
• lapses (response > 500ms)

29. Sources
1. 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 http://
www.ncbi.nlm.nih.gov/pubmed/12603781
3. Belenky, G. (1997). Sleep , Sleep Deprivation , and Human Performance in Continuous Operations, 1-13.
Retrieved from http://isme.tamu.edu/JSCOPE97/Belenky97/Belenky97.htm
4. 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 http://
www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2849789&tool=pmcentrez&rendertype=abstract
5. Robinson, E. (2005). Why Crunch Mode Doesn’t Work: 6 Lessons. IGDA Retrieved Feb, 1-6. Retrieved
from http://www.igda.org/why-crunch-modes-doesnt-work-six-lessons
6. Roenneberg, Till. Internal Time: Chronotypes, Social Jet Lag, and Why You're 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 http://www.brainpickings.org/index.php/2012/05/11/internal-time-till-roenneber/