TY - JOUR
T1 - Is There a Testosterone Awakening Response in Humans?
AU - Kuzawa, Christopher W
AU - Georgiev, Alexander V.
AU - McDade, Thomas
AU - Bechayda, Sonny Agustin
AU - Gettler, Lee T.
N1 - Funding Information:
Acknowledgments We thank the many researchers at the Office of Population Studies, University of San Carlos, Cebu, Philippines, for their central role in study design and data collection, and the Filipino participants, who generously provided their time for this study. Elizabeth Quinn, Katy Sharrock, Jeffrey Huang, Iram Azam, Divya Mallampati, Brian Dubin, and Laura Rogers helped with various phases of lab work. We thank the editor and two anonymous reviewers for their helpful comments. This study was funded by the Wenner Gren Foundation (Gr. 7356) and the National Science Foundation (BCS-0542182). Fieldwork and sample collection were supported with pilot funds from the Interdisciplinary Obesity Center (RR20649) and the Center for Environmental Health and Susceptibility (ES10126; project 7-2004-E).
Publisher Copyright:
© 2015, Springer International Publishing.
PY - 2016/6/1
Y1 - 2016/6/1
N2 - Circulating testosterone (T) follows a diurnal pattern with high waking levels that decline across the day. The hypothalamic-pituitary-adrenal axis produces cortisol in a similar manner but also undergoes an abrupt increase in hormone secretion immediately upon waking (a cortisol awakening response, CAR). Whether the hypothalamic-pituitary-gonadal axis, and circulating T levels, exhibit a similar post-waking response is unclear. Here we describe post-waking T changes in a sample of 108 young adult males from metropolitan Cebu City, the Philippines. As expected, salivary T was higher at waking than in the evening but, remarkably, 60 % of this diurnal decline occurred within 30 min of awakening. There was a strong inverse linear relationship between waking T and the post-waking T decline, such that men with higher waking T experienced a more rapid decline in the hormone. Even though fathers had lower waking T, they experienced a greater post-waking decline than non-fathers. Men with a larger positive CAR had modestly attenuated post-waking T declines. We speculate that these findings reflect a testosterone awakening response (TAR) that helps partition the target tissue effects of T by time of day. T rises overnight to facilitate muscle anabolism at a time when the hormone’s impacts on social behavior are limited. Upon waking, the rapid drop in T helps shift from anabolic to catabolic processes in support of physical activity, while also calibrating T levels in line with the competing social priorities of the individual, as determined by the current balance of behavioral investment towards mating and parental effort.
AB - Circulating testosterone (T) follows a diurnal pattern with high waking levels that decline across the day. The hypothalamic-pituitary-adrenal axis produces cortisol in a similar manner but also undergoes an abrupt increase in hormone secretion immediately upon waking (a cortisol awakening response, CAR). Whether the hypothalamic-pituitary-gonadal axis, and circulating T levels, exhibit a similar post-waking response is unclear. Here we describe post-waking T changes in a sample of 108 young adult males from metropolitan Cebu City, the Philippines. As expected, salivary T was higher at waking than in the evening but, remarkably, 60 % of this diurnal decline occurred within 30 min of awakening. There was a strong inverse linear relationship between waking T and the post-waking T decline, such that men with higher waking T experienced a more rapid decline in the hormone. Even though fathers had lower waking T, they experienced a greater post-waking decline than non-fathers. Men with a larger positive CAR had modestly attenuated post-waking T declines. We speculate that these findings reflect a testosterone awakening response (TAR) that helps partition the target tissue effects of T by time of day. T rises overnight to facilitate muscle anabolism at a time when the hormone’s impacts on social behavior are limited. Upon waking, the rapid drop in T helps shift from anabolic to catabolic processes in support of physical activity, while also calibrating T levels in line with the competing social priorities of the individual, as determined by the current balance of behavioral investment towards mating and parental effort.
KW - Cortisol
KW - Life history
KW - Mating
KW - Psychophysiology
KW - Reproductive strategies
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U2 - 10.1007/s40750-015-0038-0
DO - 10.1007/s40750-015-0038-0
M3 - Article
AN - SCOPUS:85020579834
SN - 2198-7335
VL - 2
SP - 166
EP - 183
JO - Adaptive Human Behavior and Physiology
JF - Adaptive Human Behavior and Physiology
IS - 2
ER -