| Reference code: | PT/FB/BL-2010-096.08 |
| Location: | Arquivo PCA - Pasta 8/2010
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Title:
| The cortisol awakening response: why tolerable errors in timing may not be so tolerable and why linearity of cortisol rise should not be assumed
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| Publication year: | 2013
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URL:
| http://www.psychosomatic.org/anmeeting/PDF/2013abstractBooklet.pdf
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| Abstract/Results: | ABSTRACT:
Research linking the Cortisol Awakening Response (CAR) to psychosocial and health domains needs CAR measures to be based on
accurately timed saliva samples. How accurate? Typically a CAR is big and brief, and even quite modest delays between awakening and initial saliva sample might theoretically be expected to compromise accuracy; but delays up to 15 min reportedly do not do so. This paradox is explored and predictions examined in new data for effects of moderate delays (5-15 min) on several different CAR magnitude measures, and on timing of the CAR peak. Both self-reported awakening and sampling times were objectively checked by actigraphy and track caps. 50 healthy females (21±4 years) were told to collect saliva on 4 days at 0, 15, 30 and 45 min post-awakening. Self-reports were significantly later by 8 (±11) min than objective estimates of awakening. Selfreported sampling time intervals were accurate (< 2 min mean error). Minimally delayed data (< 5 min) were compared with moderately delayed (5-15 min). CAR magnitude was significantly greater for delayed data and peaked earlier. Plots of cortisol values in real time suggested effects were due to a time lag between awakening and start of cortisol rise; cortisol rise was not linear. Further evidence for this was sought and found in an intensive investigation of 10 participants who collected saliva every 5 min from 0-30 min post-awakening. We conclude that moderate delays in saliva sampling previously thought tolerable lead to errors in estimating CAR magnitude and peak-timing, due to an approximate 10 min lag between awakening and cortisol rise. Ignoring this lag in calculations leads to overestimation of CAR magnitude, even if sampling is only moderately delayed. These findings, if generalizable, clarify how the physiology of the CAR unfolds, but are methodologically challenging for researchers since self-reported awakening times are not accurate enough to override concerns raised. Objective measurement of sampling time would, however, permit known delays to be taken into account when computing CAR estimates.
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| Accessibility: | Document does not exist in file
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Language:
| eng
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Author:
| Evans, P.
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Secondary author(s):
| Smyth, N., Thorn, L., Hucklebridge, F., Clow, A.
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Document type:
| Abstract book
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Number of reproductions:
| 1
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Reference:
| Evans, P., Smyth, N., Thorn, L., Hucklebridge, F., & Clow, A. (2013). The cortisol awakening response: why tolerable errors in timing may not be so tolerable and why linearity of cortisol rise should not be assumed. Abstracts of the American Psychosomatic Society 71st Annual Meeting: “Impact and Innovation” (A - 48). Miami, FL.
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| Indexed document: | No
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| Keywords: | Cortisol awakening response / Saliva / Sampling delay / Actigraphy / Track caps / Time lag / Sampling delay
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The cortisol awakening response: why tolerable errors in timing may not be so tolerable and why linearity of cortisol rise should not be assumed |