Sex differences in daily activity intensity and energy expenditure and their relationship to cortisol among BaYaka foragers from the Congo Basin

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

Abstract

Objectives
The pooling of energetic resources and food sharing have been widely documented among hunter-gatherer societies. Much less is known about how the energetic costs of daily activities are distributed across individuals in such groups, including between women and men. Moreover, the metabolic physiological correlates of those activities and costs are relatively understudied.

Materials and methods
Here, we tracked physical activity, energy expenditure (EE), and cortisol production among Congo Basin BaYaka foragers engaged in a variety of daily subsistence activities (n = 37). Given its role in energy mobilization, we measured overall daily cortisol production and short-term cortisol reactivity through saliva sampling; we measured physical activity levels and total EE via the wGT3X-bt actigraph and heart rate monitor.

Results
We found that there were no sex differences in likelihood of working in common activity locations (forest, garden, house). Across the day, women spent greater percentage time in moderate-to-vigorous physical activity (%MVPA) and had lower total EE than men. Females with higher EE (kCal/hr) produced greater cortisol throughout the day. Though not statistically significant, we also found that individuals with greater %MVPA had larger decreases in cortisol reactivity.

Discussion
BaYaka women sustained higher levels of physical activity but incurred lower energetic costs than men, even after factoring in sex differences in body composition. Our findings suggest that the distribution of physical activity demands and costs are relevant to discussions regarding how labor is divided and community energy budgets take shape in such settings.

Citation

Sarma, M. S., Boyette, A. H., Lew-Levy, S., Miegakanda, V., Kilius, E., Samson, D. R., & Gettler, L. T. (2020). Sex differences in daily activity intensity and energy expenditure and their relationship to cortisol among BaYaka foragers from the Congo Basin. American journal of physical anthropology, 172(3), 423-437. https://doi.org/10.1002/ajpa.24075

• Journal Article Type: Article
• Acceptance Date: Apr 17, 2020
• Online Publication Date: May 22, 2020
• Publication Date: 2020-07
• Deposit Date: Sep 11, 2023
• Journal: American Journal of Physical Anthropology
• Print ISSN: 0002-9483
• Electronic ISSN: 1096-8644
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 172
• Issue: 3
• Pages: 423-437
• DOI: https://doi.org/10.1002/ajpa.24075
• Public URL: https://durham-repository.worktribe.com/output/1734320