Investigation of Humidity Regulation and Heart Rate Variability in Indoor Environments with <i>Larix kaempferi</i> Wood Interiors

Wood, as a natural material that stores carbon, is gaining increasing attention and has potential for use in interior architectural applications. Given the long indoor stay time characteristic of modern society, it is important to scientifically understand the effects of indoor wood application on t...

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Main Authors: Su-Yeon Lee, Yoon-Seong Chang, Chang-Deuk Eom, Oh-Won Kwon, Chun-Young Park
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Applied Sciences
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Online Access:https://www.mdpi.com/2076-3417/15/15/8392
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author Su-Yeon Lee
Yoon-Seong Chang
Chang-Deuk Eom
Oh-Won Kwon
Chun-Young Park
author_facet Su-Yeon Lee
Yoon-Seong Chang
Chang-Deuk Eom
Oh-Won Kwon
Chun-Young Park
author_sort Su-Yeon Lee
collection DOAJ
description Wood, as a natural material that stores carbon, is gaining increasing attention and has potential for use in interior architectural applications. Given the long indoor stay time characteristic of modern society, it is important to scientifically understand the effects of indoor wood application on the occupants. In this study, three residential buildings with an identical area and structure were constructed with different degrees of wood coverage (0%, 45%, 90%) using <i>Larix kaempferi</i>. Subsequently, indoor air quality (IAQ) evaluations and relative humidity measurements were conducted to assess the physical and chemical changes in each environment. The IAQ in wooden and non-wooden environments met the recommended IAQ standards established in South Korea. The results of the 8-month observation showed that, the higher the wood coverage ratio, the more the indoor humidity fluctuations were alleviated, and, in the case of the 90% wood coverage ratio condition, the humidity was maintained 5.2% lower in the summer and 10.9% higher in the winter compared to the 0% condition. To further assess the physiological responses induced by the wooden environment, the heart rate variability (HRV) was measured and compared for 26 participants exposed to each environment for two hours. In environments with a 0% and 90% degree of wood coverage, no statistically significant differences were found in the participants’ HRV indicators. But, in the group exposed to the 45% wooden environment, the results showed an increase in HRV indicators, natural logarithm of high frequency power (lnHF): 4.87 → 5.40 (<i>p</i> < 0.05), and standard deviation of normal-to-normal intervals (SDNN): 30.57 → 38.48 (<i>p</i> < 0.05), which are known indicators of parasympathetic nervous system activation.
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spelling doaj-art-aca0a782e0cd4dc39604cced12c6ace82025-08-20T03:35:57ZengMDPI AGApplied Sciences2076-34172025-07-011515839210.3390/app15158392Investigation of Humidity Regulation and Heart Rate Variability in Indoor Environments with <i>Larix kaempferi</i> Wood InteriorsSu-Yeon Lee0Yoon-Seong Chang1Chang-Deuk Eom2Oh-Won Kwon3Chun-Young Park4National Institute of Forest Science, Seoul 02455, Republic of KoreaNational Institute of Forest Science, Seoul 02455, Republic of KoreaNational Institute of Forest Science, Seoul 02455, Republic of KoreaKorea Association of Wood Culture, Seoul 02455, Republic of KoreaKorea Association of Wood Culture, Seoul 02455, Republic of KoreaWood, as a natural material that stores carbon, is gaining increasing attention and has potential for use in interior architectural applications. Given the long indoor stay time characteristic of modern society, it is important to scientifically understand the effects of indoor wood application on the occupants. In this study, three residential buildings with an identical area and structure were constructed with different degrees of wood coverage (0%, 45%, 90%) using <i>Larix kaempferi</i>. Subsequently, indoor air quality (IAQ) evaluations and relative humidity measurements were conducted to assess the physical and chemical changes in each environment. The IAQ in wooden and non-wooden environments met the recommended IAQ standards established in South Korea. The results of the 8-month observation showed that, the higher the wood coverage ratio, the more the indoor humidity fluctuations were alleviated, and, in the case of the 90% wood coverage ratio condition, the humidity was maintained 5.2% lower in the summer and 10.9% higher in the winter compared to the 0% condition. To further assess the physiological responses induced by the wooden environment, the heart rate variability (HRV) was measured and compared for 26 participants exposed to each environment for two hours. In environments with a 0% and 90% degree of wood coverage, no statistically significant differences were found in the participants’ HRV indicators. But, in the group exposed to the 45% wooden environment, the results showed an increase in HRV indicators, natural logarithm of high frequency power (lnHF): 4.87 → 5.40 (<i>p</i> < 0.05), and standard deviation of normal-to-normal intervals (SDNN): 30.57 → 38.48 (<i>p</i> < 0.05), which are known indicators of parasympathetic nervous system activation.https://www.mdpi.com/2076-3417/15/15/8392<i>Larix kaempferi</i>wooden interiorshumidity regulationphysiological responses
spellingShingle Su-Yeon Lee
Yoon-Seong Chang
Chang-Deuk Eom
Oh-Won Kwon
Chun-Young Park
Investigation of Humidity Regulation and Heart Rate Variability in Indoor Environments with <i>Larix kaempferi</i> Wood Interiors
Applied Sciences
<i>Larix kaempferi</i>
wooden interiors
humidity regulation
physiological responses
title Investigation of Humidity Regulation and Heart Rate Variability in Indoor Environments with <i>Larix kaempferi</i> Wood Interiors
title_full Investigation of Humidity Regulation and Heart Rate Variability in Indoor Environments with <i>Larix kaempferi</i> Wood Interiors
title_fullStr Investigation of Humidity Regulation and Heart Rate Variability in Indoor Environments with <i>Larix kaempferi</i> Wood Interiors
title_full_unstemmed Investigation of Humidity Regulation and Heart Rate Variability in Indoor Environments with <i>Larix kaempferi</i> Wood Interiors
title_short Investigation of Humidity Regulation and Heart Rate Variability in Indoor Environments with <i>Larix kaempferi</i> Wood Interiors
title_sort investigation of humidity regulation and heart rate variability in indoor environments with i larix kaempferi i wood interiors
topic <i>Larix kaempferi</i>
wooden interiors
humidity regulation
physiological responses
url https://www.mdpi.com/2076-3417/15/15/8392
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AT changdeukeom investigationofhumidityregulationandheartratevariabilityinindoorenvironmentswithilarixkaempferiiwoodinteriors
AT ohwonkwon investigationofhumidityregulationandheartratevariabilityinindoorenvironmentswithilarixkaempferiiwoodinteriors
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