Interstitial cortisol measurements aligned by wake time, healthy volunteers

Background: Cortisol is released upon activation of the hypothalamic-pituitary-adrenal axis, varies across the day, and possesses an underlying diurnal rhythm reactive and responsive to stressors. While the endogenous peak of cortisol occurs in the morning, the observed cortisol rise post-awakening has been named the cortisol awakening response (CAR) based on the belief that the act of waking up stimulates cortisol secretion. However, objective evidence that awakening universally induces cortisol secretion is limited.
Methods: We used a mixed effects model with a linear spline fitted to the data to examine tissue free cortisol measurements obtained from 201 healthy volunteers by automated ambulatory microdialysis before and after awakening in their home environments. We also examined rate of change of cortisol depending on sleep duration and relative timing.
Results: We found no evidence for a change in the rate of cortisol increase in the hour after waking when compared with the hour p..., This dataset contains serial measurements of cortisol collected by ambulatory microdialysis as described in https://doi.org/10.1126/scitranslmed.adg8464
The original data available at https://doi.org/10.18710/5TW8YF have been processed using Python code to realign time series for each participant relative to wake time.
There are 5 CSV files containing the following fields:
\"value\" : measurements of cortisol in nmol/L
\"minutes\" : time (in minutes) of the observation relative to wake time
\"bins\" : the 20 minute time range the observation occured within, placeholder only, not used for analysis
\"SID\" : subject identifier - anonymised, identifies each unique participant
There is one .R code file:
contains code to run mixed linear models using the CSV files in the repository. Version of R and R packages included in the code file, , # Interstitial cortisol measurements aligned by wake time, healthy volunteers

[https://doi.org/10.5061/dryad.2280gb62w](https://doi.org/10.5061/dryad.2280gb62w)

## Description of the data and file structure

The aim of this analysis was to investigate whether waking was associated with an increase in tissue free cortisol in a cohort of night-sleeping healthy volunteers, free from active medical diagnoses or regular medication, and who chose their own sleep period. To do this, we analysed data collected as part of the Dynamic Hormone Diagnostics (ULTRADIAN) observational cohort study (NCT02934399) and available in a public repository (UiB Open Research Data, https://doi.org/10.18710/5TW8YF).

The methods of data collection and preparation are described in detail in Upton, Zavala, Methlie et al. (2023) but briefly, involved the use of a portable microdialysis-based sampling system that enabled continuous sampling in subcutaneous tissue. Each participant completed a 24-hour sampling ses...