Access to Electric Light Is Associated with Shorter Sleep Duration - PowerPoint PPT Presentation

Access to Electric Light Is Associated with Shorter Sleep Duration in Toba Communities of The Argentinean Chaco Horacio O. de la Iglesia Eduardo Fernández-Duque Norberto Lanza Diego A. Golombek Jeanne F. Duffy Charles D. Czeisler and Claudia R. Valeggia

Components of Mammalian Circadian System Clock Overt circadian rhythms Environmental Photoreceptors (suprachiasmatic nucleus) (e.g. sleep-wake cycle) Cycle (retina) (e.g.. light-dark cycle) Output Input pathways pathways I IX III VI

The circadian system is highly sensitive to light resetting Flying squirrels can be entrained by one second of light per day one second!

The human circadian system can be reset by artificial light

Could our ancestral sleep timing have changed by the access to artificial light, particularly electric light?

The Toba uá árez Latitude: 23º 47min Longitude: 61º 48min

Activity data loggers

November (summer) 900 800 700 600 500 400 300 900 200 800 Locomotor activity 100 700 600 0 1000 1060 1120 1180 1240 1300 1360 time 40 100 160 220 280 340 400 460 520 580 640 700 760 820 880 940 500 400 300 900 200 800 100 700 0 0 80 160 240 320 400 480 560 640 720 800 880 960 1040 1120 1200 1280 1360 600 16 20 00 4 8 12 12 500 Clock time 400 300 200 100 0 time 40 100 160 220 280 340 400 460 520 580 640 700 760 820 880 940 1000 1060 1120 1180 1240 1300 1360 16 20 00 4 8 12 12 Clock time Sunset Sunrise

November (summer) Rise time Bedtime Time in bed Sleep Sleep NO-electricity onset offset Sleep duration Rise Bedtime time Time in * bed Sleep Sleep Electricity onset offset Sleep † duration 1700 2200 0300 0800 1300 Clock time

August (winter) 900 800 700 Locomotor activity 600 500 400 300 200 100 0 0 80 160 240 320 400 480 560 640 720 800 880 960 1040 1120 1200 1280 1360 16 20 00 4 8 12 12 Clock time Sunset Sunrise

August (winter) Rise time Bedtime Time in bed Sleep Sleep NO-electricity onset offset Sleep duration Rise time Bedtime Time in * bed Sleep Sleep Electricity onset offset Sleep † ¥ duration 1700 2200 0300 0800 1300 Clock time

NO-electricity Get up Bedtime time Time in bed Sleep Sleep Winter onset offset Sleep duration Get up Bedtime time Time in bed Sleep Sleep Summer onset offset Sleep # ¥ duration 1700 2200 0300 0800 1300 Clock time

Electricity Rise Bedtime time Time in bed Sleep Sleep Winter onset offset Sleep duration Rise Bedtime time Time in * bed Sleep Sleep Summer onset offset Sleep ¥ duration 1700 2200 0300 0800 1300 Clock time

Acknowledgments The Toba communities of Sombrero Negro and Barrio Qompi. Thank you for your friendship!