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Hormone physiology and sleep dynamics among BaYaka foragers of the Congo Basin: Gendered associations between nighttime activity, testosterone, and cortisol

Gettler, Lee T; Samson, David R; Kilius, Erica; Sarma, Mallika S; Miegakanda, Valchy; Lew-Levy, Sheina; Boyette, Adam H

Authors

Lee T Gettler

David R Samson

Erica Kilius

Mallika S Sarma

Valchy Miegakanda

Adam H Boyette



Abstract

Sleep quality is an important contributor to health disparities and affects the physiological function of the immune and endocrine systems, shaping how resources are allocated to life history demands. Past work in industrial and post-industrial societies has shown that lower total sleep time (TST) or more disrupted nighttime sleep are linked to flatter diurnal slopes for cortisol and lower testosterone production. There has been little focus on these physiological links in other socio-ecological settings where routine sleep conditions and nighttime activity demands differ. We collected salivary hormone (testosterone, cortisol) and actigraphy-based sleep data from Congolese BaYaka foragers (N = 39), who have relatively short and fragmented nighttime sleep, on average, in part due to their typical social sleep conditions and nighttime activity. The hormone and sleep data collections were separated by an average of 11.23 days (testosterone) and 2.84 days (cortisol). We found gendered links between nighttime activity and adults' hormone profiles. Contrary to past findings in Euro-American contexts, BaYaka men who were more active at night, on average, had higher evening testosterone than those with lower nighttime activity, with a relatively flat slope relating nighttime activity and evening testosterone in women. Women had steeper diurnal cortisol curves with less disrupted sleep. Men had steeper cortisol diurnal curves if they were more active at night. BaYaka men often hunt and socialize when active at night, which may help explain these patterns. Overall, our findings indicate that the nature of nighttime activities, including their possible social and subsistence contexts, are potentially important modifiers of sleep quality-physiology links, meriting further research across contexts.

Citation

Gettler, L. T., Samson, D. R., Kilius, E., Sarma, M. S., Miegakanda, V., Lew-Levy, S., & Boyette, A. H. (2023). Hormone physiology and sleep dynamics among BaYaka foragers of the Congo Basin: Gendered associations between nighttime activity, testosterone, and cortisol. Hormones and Behavior, 155, Article 105422. https://doi.org/10.1016/j.yhbeh.2023.105422

Journal Article Type Article
Acceptance Date Aug 21, 2023
Online Publication Date Sep 6, 2023
Publication Date 2023-09
Deposit Date Sep 11, 2023
Journal Hormones and Behavior
Print ISSN 0018-506X
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 155
Article Number 105422
DOI https://doi.org/10.1016/j.yhbeh.2023.105422
Public URL https://durham-repository.worktribe.com/output/1734532