Correlations Detected Between Transepidermal Water Loss and Barrier Repair Kinetics, Heart Rate Variability

Skin barrier repair kinetics (sympathetic activity) and heart rate variability (parasympathetic activity) were found to be correlated in a recent study published in Skin Research and Technology.¹

According to researchers, this is the first known study to correlate epidermal barrier recovery kinetics with autonomic nervous system activity over a 24-hour duration.

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Background and Methods

Studies in both rodents and humans have shown that psychological stress disrupts barrier function, a process that is reversible with the use of sedatives and glucocorticoid receptor antagonists.²

In rodents, psychological stress activates the hypothalamic-pituitary-adrenal axis, leading to the secretion of glucocorticoid, which suppresses immune responses and impairs barrier function. Similar mechanisms are also observed in humans, where psychological stress correlates with elevated plasma glucocorticoid levels, increased skin infections, and exacerbated conditions such as atopic dermatitis.³

The study was designed as a non-invasive, experimental skin bioengineering trial including 20 skin-healthy female volunteers (Fitzpatrick skin phototype I-II), aged 21-32 years.

Researchers measured skin surface pH using a flat glass electrode, assessed barrier function by measuring transepidermal water loss (TEWL) with a Tewameter TM300, and evaluated barrier integrity through tape stripping on the volar forearm using commercially available adhesive tape.

They also recorded electrodermal activity using MentalBioScreen K3, with electrodes placed on the right-hand thenar/hypothenar sites. Heart rate was recorded using the eMotion ECG sensor, and heart rate variability was analyzed with the HRV Scanner software. Participants also completed a standardized 24-item Trierer Inventar zum chronischen Stress questionnaire.

Participants acclimatized for 30 minutes in a controlled environment before TEWL measurements were taken. Following experimental barrier perturbation via tape stripping, electrodes were placed for 24-hour recordings. TEWL measures were taken again after 24 hours, following a 30-minute rest period.

Findings

Key findings revealed a significant negative correlation between heart rate variability and delta TEWL after 24 hours, indicating that higher heart rate variability was associated with better barrier recovery. This was observed during both diurnal and nocturnal phases.

Furthermore, a positive correlation between heart rate variability and percent barrier regeneration after 24 hours was noted, which researchers argue is suggestive of a higher heart rate variability being linked to improved barrier regeneration.

No significant correlation was found between electrodermal activity measurements and barrier recovery kinetics. However, a negative correlation between these measurements and skin surface pH prior to perturbation was observed.

No correlation was found between questionnaire results and either skin physiological or psychophysiological measures.

Conclusions

These findings align with previous research demonstrating that psychological stress negatively impacts skin barrier function, corroborating the observed correlations between heart rate variability and barrier recovery.²

Electrodermal activity parameters did not correlate with barrier recovery kinetics, possibly due to the variability in sympathetic-controlled sweat gland activity. However, the significant negative correlation between baseline electrodermal activity and skin surface pH may suggest that sympathetic nerve activity influences skin surface pH.

"In the presented non-invasive, experimental, skin bioengineering trial, significant correlations were shown for skin barrier repair kinetics (sympathetic activity) and heart rate variability (parasympathetic activity). Further correlations were noted for electrodermal activity and skin surface pH," wrote study authors Schürer et al. "The presented approach may provide a basis for non-invasive objective research on the correlation between psychological stressors and epidermal barrier function in the future."

References

1. Schürer NY, Symanzik C, Kukshausen O, Stürmer R. Correlation of non-invasive psycho-physiological and skin-physiological measures. Skin Res Technol. Published online June 9, 2024. https://doi.org/10.1111/srt.13745
2. Garg A, Chren MM, Sands LP, et al. Psychological stress perturbs epidermal permeability barrier homeostasis: implications for the pathogenesis of stress-associated skin disorders. Arch Dermatol. 2001; 137(1): 53-59.
3. Denda M, Tsuchiya T, Elias PM, Feingold KR. Stress alters cutaneous permeability barrier homeostasis. Am J Physiol Regul Integr Comp Physiol. 2000; 278(2): R367-R372.