Deceleration Capacity and Periodic Repolarization Dynamics As Predictors of Acute Mountain Sickness.

Hamm, Wolfgang, Sari Kassem, Lukas von Stülpnagel, Florian Maier, Mathias Klemm, Dominik Schüttler, Felix Grabher, Ludwig T. Weckbach, Bruno C. Huber, Axel Bauer, Konstantinos D. Rizas, and Stefan Brunner. Deceleration capacity and periodic repolarization dynamics as predictors of acute mountain sickness. High Alt Med Biol. 21:417-422, 2020. Background: The autonomic nervous system plays an important role in adaptive changes after acute altitude exposure. Periodic repolarization dynamics (PRD) and deceleration capacity (DC) of heart rate are advanced electrocardiogram (ECG)-based parameters reflecting sympathetic (PRD) and parasympathetic (DC) tone. These parameters have not been investigated in the context of acute mountain sickness (AMS) yet. Methods: In 23 healthy individuals (13 women), a high-resolution digital 30-minute ECG in Frank leads configuration was performed in a resting supine position at baseline (521 m altitude) and after a sojourn of 24 hours at the Environmental Research Station Schneefernerhaus (UFS) at Zugspitze (2,650 m altitude). PRD and DC were assessed using validated software. Symptoms of AMS were assessed with the Lake Louise Acute Mountain Sickness Score (LLS). Results: During altitude exposure, PRD significantly increased from 1.50 ± 1.01 (mean ± standard deviation) deg2 to 3.51 ± 4.46 deg2 (p = 0.03). DC significantly decreased from 11.48 ± 2.91 ms to 9.94 ± 2.78 ms (p = 0.001). An increase of PRD and/or a decrease of DC correlated significantly with the level of LLS. The combined finding of an increase of PRD and a decrease of DC had a sensitivity of 100% and a specificity of 76.5% to diagnose AMS (LLS ≥3). Receiver operating characteristic (ROC) analysis showed an AUC (area under the ROC curve) of 0.77. Linear regression analysis revealed a significant association between LLS and an increase in PRD during high-altitude exposure. Conclusions: Our findings show an increase of PRD and a decrease of DC during altitude exposure. Combined PRD and DC analysis may have potential for the diagnosis of AMS.

The Association of Hair Cortisol with Self-Reported Chronic Psychosocial Stress and Symptoms of Anxiety and Depression in Women Shortly after Delivery.

BACKGROUND: Psychosocial stress during pregnancy including anxiety and depression is known to have adverse health effects on newborns. However, measuring these psychological constructs is complex with psychological, endocrinological, and physiological systems being affected. Hair cortisol concentrations (HCC), assumed to reflect long-term endocrine consequences of stress exposure, represent a promising instrument for epidemiological research. However, the association between HCC and questionnaire-based instruments is unclear. METHODS: In the Ulm SPATZ Health Study, mothers were recruited shortly after delivery in the University Medical Centre Ulm, Germany between April 2012 and May 2013. HCC of 768 participants were determined in scalp-near 3 cm maternal hair segments, assumed to reflect cortisol exposure over the last trimester of pregnancy. Chronic stress, anxiety, and depressive symptomatology were self-reported in questionnaire-based instruments. Spearman correlation coefficients between HCC and these instruments as well as means of HCC in highly and low stressed subgroups were calculated. RESULTS: HCC were not correlated with self-reported chronic stress, anxiety, or depressive symptomatology. Furthermore, the investigation of sub-populations did not reveal substantial differences of HCC across highly and low stressed women. CONCLUSIONS: HCC were not found to correlate with self-reports of chronic stress, anxiety, or depressive symptomatology. Among other things, these findings could reflect problems with questionnaire-based assessments obtained shortly after delivery such as recall bias and/or suggest that associations between cortisol secretion and psychosocial stress are difficult to detect due to, e.g. a strong physiological increase of cortisol in the last trimester.

Determinants of maternal hair cortisol concentrations at delivery reflecting the last trimester of pregnancy.

Hair cortisol concentrations (HCC) are emerging as a promising marker of chronic psychosocial stress. However, limited information on relevant correlates of this biomarker in late pregnancy is available. In the Ulm SPATZ Health Study mothers were recruited between 04/2012 and 05/2013 shortly after delivery in the University Medical Center Ulm, Germany. Cortisol concentrations of N=768 participants were determined by HPLC-MS/MS in the scalp-near 3cm of maternal hair reflecting stress exposure over the preceding three months. Sociodemographic characteristics, pregnancy-related variables and comorbidities were assessed. We conducted bivariate and multiple linear regression analyses using log transformed HCC. In bivariate analyses, significantly higher cortisol concentrations were found in obese compared to normal weight (b=0.32, p<0.001) and smoking as opposed to non-smoking mothers (b=0.34, p=0.002). Conversely, primary C-section was associated with lower HCC compared to spontaneous delivery. Besides, a strong impact of season of delivery with significantly higher HCC in summer and autumn as opposed to winter (both bs=0.58, p<0.001) was found. Further determinants of HCC were maternal education, number of persons in the household, premature delivery and hair characteristics. In a mutually adjusted model, all but education, multiple jobholding, hair characteristics and premature delivery remained statistically significant. Maternal hair cortisol in the last trimester of pregnancy is determined by many factors. Delivery mode, body mass index and season of delivery should be considered when investigating the association between HCC and further outcomes in mothers shortly after delivery.