Publications

Original Publication

CARWatch was introduced in the following publication:

Richer, R., Abel, L., Küderle, A., Eskofier, B. M., & Rohleder, N. (2023). CARWatch - A smartphone application for improving the accuracy of cortisol awakening response sampling. Psychoneuroendocrinology, 151, 106073. https://doi.org/10.1016/j.psyneuen.2023.106073

This paper describes the original motivation for CARWatch and its use in improving the accuracy of cortisol awakening response sampling.

Citation

If you use CARWatch in your work, please cite the publication above and report the version you used where appropriate.

Scientific Background

CARWatch is a tool for supporting more objective assessment of cortisol awakening response sampling in real-world settings. This motivation is closely aligned with the expert consensus literature on CAR assessment.

In their 2016 expert consensus guidelines, Stalder and colleagues emphasized that CAR data are only interpretable when sampling starts at awakening and the timing of subsequent samples is controlled as closely as possible in field settings:

Stalder, T., Kirschbaum, C., Kudielka, B. M., Adam, E. K., Pruessner, J. C., Wüst, S., Dockray, S., Smyth, N., Evans, P., Hellhammer, D. H., Miller, R., Wetherell, M. A., Lupien, S. J., & Clow, A. (2016). Assessment of the cortisol awakening response: Expert consensus guidelines. Psychoneuroendocrinology, 63, 414–432. https://doi.org/10.1016/j.psyneuen.2015.10.010

The central methodological issue is that CAR estimates are highly sensitive to even short delays between awakening and the first saliva sample. In unsupervised field studies, those deviations are often difficult to detect when researchers rely only on self-reported sampling times.

CARWatch was developed to address this specific problem by combining reminders, barcode-based recording of sample events, and standardized log export. In the original validation work, this supported more precise timing and more reliable field-based CAR assessment.

The broader relevance of this issue was reinforced in the 2022 update of the consensus guidelines, which concluded that key methodological recommendations are still not consistently implemented across CAR studies and called for continued attention to timing accuracy and reporting standards:

Stalder, T., Lupien, S. J., Kudielka, B. M., Adam, E. K., Pruessner, J. C., Wüst, S., Dockray, S., Smyth, N., Evans, P., Kirschbaum, C., Miller, R., Wetherell, M. A., Finke, J. B., Klucken, T., & Clow, A. (2022). Evaluation and update of the expert consensus guidelines for the assessment of the cortisol awakening response (CAR). Psychoneuroendocrinology, 146, 105946. https://doi.org/10.1016/j.psyneuen.2022.105946

Publications that used CARWatch

As of April 2026, the following publications have used CARWatch in their research:

Richer, R., Küderle, A., Dörr, J., Rohleder, N., & Eskofier, B. M. (2021). Assessing the Influence of the Inner Clock on the Cortisol Awakening Response and Pre-Awakening Movement. 2021 IEEE EMBS International Conference on Biomedical and Health Informatics (BHI), 1–4. https://doi.org/10.1109/BHI50953.2021.9508529

Did you use CARWatch in your own publication? Let us know at robert.richer@fau.de.