{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,2]],"date-time":"2025-10-02T00:41:19Z","timestamp":1759365679985,"version":"build-2065373602"},"reference-count":41,"publisher":"MDPI AG","issue":"19","license":[{"start":{"date-parts":[[2025,10,1]],"date-time":"2025-10-01T00:00:00Z","timestamp":1759276800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["www.mdpi.com"],"crossmark-restriction":true},"short-container-title":["Sensors"],"abstract":"<jats:p>This study investigated the physiological effects of seat vibration during prolonged sitting in a simulated autonomous driving environment. Eleven healthy participants (3 young adults and 8 older adults) viewed a 120-min highway driving video under two conditions: rhythmic seat vibration (2 Hz, mimicking natural respiration) and no vibration. Physiological and behavioral metrics\u2014including Psychomotor Vigilance Task (PVT), seat pressure distribution, heart rate variability (HRV), body acceleration, and skin temperature\u2014were assessed across three phases. Results demonstrated that seat vibration significantly enhanced parasympathetic activity, as evidenced by increased HF power and decreased LF\/HF ratio (p &lt; 0.05), suggesting reduced autonomic stress. Additionally, seated posture remained more stable under vibration, with reduced asymmetry and sway, while the no-vibration condition showed time-dependent postural degradation. Interestingly, skin surface temperature was lower in the vibration condition (p &lt; 0.001), indicating a possible thermoregulatory mechanism. In contrast, PVT performance revealed more false starts in the vibration condition, particularly among older adults, suggesting that vibration may not enhance\u2014and could slightly impair\u2014cognitive alertness. These findings suggest that low-frequency seat vibration can support physiological stability and postural control during prolonged sedentary conditions, such as in autonomous vehicles. However, its effects on vigilance appear limited and age-dependent. Overall, rhythmic vibration may contribute to enhancing passenger comfort and reducing fatigue-related risks, particularly in older individuals. Future work should explore adaptive vibration strategies to balance physiological relaxation and cognitive alertness in mobility environments.<\/jats:p>","DOI":"10.3390\/s25196039","type":"journal-article","created":{"date-parts":[[2025,10,1]],"date-time":"2025-10-01T09:37:21Z","timestamp":1759311441000},"page":"6039","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Effects of Seat Vibration on Biometric Signals and Postural Stability in a Simulated Autonomous Driving Environment"],"prefix":"10.3390","volume":"25","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1865-7735","authenticated-orcid":false,"given":"Emi","family":"Yuda","sequence":"first","affiliation":[{"name":"Innovation Center for Semiconductor and Digital Future, Mie University, Tsu 514-0102, Japan"},{"name":"Department of Management Science and Technology, Graduate School of Engineering, Tohoku University, Sendai 980-8577, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5676-3048","authenticated-orcid":false,"given":"Yutaka","family":"Yoshida","sequence":"additional","affiliation":[{"name":"Faculty of Engineering, Mie University, Tsu 514-0102, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kunio","family":"Sato","sequence":"additional","affiliation":[{"name":"Alps Alpine Co., Ltd., Tokyo 145-8501, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hideki","family":"Sakamoto","sequence":"additional","affiliation":[{"name":"Alps Alpine Co., Ltd., Tokyo 145-8501, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Makoto","family":"Takahashi","sequence":"additional","affiliation":[{"name":"Department of Management Science and Technology, Graduate School of Engineering, Tohoku University, Sendai 980-8577, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,10,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"37","DOI":"10.1016\/S0161-4754(00)90112-X","article-title":"Sitting biomechanics, part II: Optimal car driver\u2019s seat and optimal driver\u2019s spinal model","volume":"23","author":"Harrison","year":"2000","journal-title":"J. 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