It looks good, although only two groups were sampled. It is worth noting that the “sleep period” was from 6.9 to 8.5 hr—that is, while they were resting in bed.
The article is pretty clear on why this might be the case:
“In these societies, electricity and its associated lighting and entertainment distractions are absent, as are cooling and heating systems. Individuals are exposed, from birth, to sunlight and a continuous seasonal and daily variation in temperature within the thermoneutral range for much of the daylight period, but above thermoneutral temperatures in the afternoon and below thermoneutrality at night.”
“The Tsimane and San live far enough south of the equator to have substantial seasonal changes in day length and temperature.”
“Because we noticed that the Hadza, Tsimane, and San did not initiate sleep at sunset and that their sleep was confined to the latter portion of the dark period, we investigated the role of temperature. We found that the nocturnal sleep period in the Hadza was always initiated during a period of falling ambient temperature, and we saw a similar pattern in the Tsimane. Therefore, we precisely measured ambient temperature at the sleeping sites along with finger temperature and abdominal temperature in our studies of the San. Figures 4 and S1 show that sleep in both the winter and summer occurred during the period of decreasing ambient temperature and that wake onset occurred near the nadir of the daily temperature rhythm. A strong vasoconstriction occurred at wake onset in both summer and winter, presumably functioning to aid thermogenesis in raising the brain and core temperature for waking activity. ”
Edit: I don’t know how to link an article with parentheses in the URL.
I should add a TLDR for LessWrongers interested in sleep patterns: if you are having trouble sleeping, you should consider temperature as a variable, perhaps more so than light. Napping was not a significant factor, but was present. Segmented sleep was not observed in this study. Sleep times were longer in the winter than in the summer by an average of 53 minutes.
I don’t have enough trouble with my own sleep to make the experiment very useful or decisive, but now that the nights are getting colder, it would be interesting to see what would happen if some LessWrongers experimented with space heaters on timers; set them to go off about 15 minutes before you want to wake up, and see it helps.
Full Article
It looks good, although only two groups were sampled. It is worth noting that the “sleep period” was from 6.9 to 8.5 hr—that is, while they were resting in bed.
The article is pretty clear on why this might be the case:
“In these societies, electricity and its associated lighting and entertainment distractions are absent, as are cooling and heating systems. Individuals are exposed, from birth, to sunlight and a continuous seasonal and daily variation in temperature within the thermoneutral range for much of the daylight period, but above thermoneutral temperatures in the afternoon and below thermoneutrality at night.”
“The Tsimane and San live far enough south of the equator to have substantial seasonal changes in day length and temperature.”
“Because we noticed that the Hadza, Tsimane, and San did not initiate sleep at sunset and that their sleep was confined to the latter portion of the dark period, we investigated the role of temperature. We found that the nocturnal sleep period in the Hadza was always initiated during a period of falling ambient temperature, and we saw a similar pattern in the Tsimane. Therefore, we precisely measured ambient temperature at the sleeping sites along with finger temperature and abdominal temperature in our studies of the San. Figures 4 and S1 show that sleep in both the winter and summer occurred during the period of decreasing ambient temperature and that wake onset occurred near the nadir of the daily temperature rhythm. A strong vasoconstriction occurred at wake onset in both summer and winter, presumably functioning to aid thermogenesis in raising the brain and core temperature for waking activity. ”
Edit: I don’t know how to link an article with parentheses in the URL.
Edit edit: now I do. Thank you, Gunnar_Zarncke.
I should add a TLDR for LessWrongers interested in sleep patterns: if you are having trouble sleeping, you should consider temperature as a variable, perhaps more so than light. Napping was not a significant factor, but was present. Segmented sleep was not observed in this study. Sleep times were longer in the winter than in the summer by an average of 53 minutes.
Thank you very much for the explanation.
You can escape the brackets by replacing with with %28 and %29.
I don’t have enough trouble with my own sleep to make the experiment very useful or decisive, but now that the nights are getting colder, it would be interesting to see what would happen if some LessWrongers experimented with space heaters on timers; set them to go off about 15 minutes before you want to wake up, and see it helps.