Circadian Rhythms and the Embodiment of Social Zeitgebers: Linking the \u3cem\u3eBio\u3c/em\u3e and \u3cem\u3eSocial\u3c/em\u3e

Virtually all biological processes are under direct or indirect control of the circadian system. Chronic disruption of circadian rhythms, termed chronodisruption, is linked to increased risk for adverse health outcomes such as cancer, depression, and cardiometabolic disease. Circadian rhythms are highly sensitive to sociocultural contexts. As a result, circadian rhythms provide a valuable entryway to explore issues of embodiment. Here, embodiment refers to processes through which social experiences ‘get under the skin’ to become biological and manifest in health. To better understand what proximate social factors influence chronodisruption, this study assessed chronodisruption and social zeitgebers among a population of 15 college students (mean age = 24±7.10 years). Social zeitgebers are any persons, social demands, or tasks that have the potential to influence an individual’s circadian rhythms. This research used wearable devices, interviews, questionnaires, and a photo food journal app to assess free-living circadian rhythms, measure social zeitgebers, and draw out narratives concerning the cultural ecology of circadian rhythms. Chronodisruption was linked to a flattened wrist temperature rhythm, irregular eating times, and greater preoccupation with schoolwork and Light Emitting Device (LED) use before bed. Nearly all participants, even those without chronodisruption, ate after 8:00 pm, skipped breakfast, went to bed after midnight, and used LEDs after sundown. Blackout curtains and class schedules that started at different times on different days were each identified as potentially novel risk factors for chronodisruption. Conversely, hydration status and the university dining program were each identified as potential protective buffers against chronodisruption. The insights generated by this study will help anthropology as a field further delineate the health consequences of political, cultural, and socio-economic influences on circadian rhythms. This information is critical for informing biocultural perspectives and interventions for supporting health in this era of obesity, diabetes, heart disease, hypertension, cancer, and depression