Effects of the green view index on anxiety reduction and perceived exertion during cycling in older adults

Tsai-Chiao Wang; Ta-Wei Tang; Shang-Min Ma; Tsu-Kung Lin; Chia-Liang Tsai

doi:10.1016/j.exger.2025.112820

Effects of the green view index on anxiety reduction and perceived exertion during cycling in older adults

Exp Gerontol. 2025 Jun 30:208:112820. doi: 10.1016/j.exger.2025.112820. Online ahead of print.

Authors

Tsai-Chiao Wang¹, Ta-Wei Tang², Shang-Min Ma³, Tsu-Kung Lin⁴, Chia-Liang Tsai⁵

Affiliations

¹ General Research Service Center, National Pingtung University of Science and Technology, Taiwan.
² Department of Business Administration, Asia University, Taiwan. Electronic address: twtang5@gmail.com.
³ Department of Recreational Sport and Health Promotion, National Pingtung University of Science and Technology, Taiwan.
⁴ Department of Neurology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taiwan; Center for Parkinson's Disease, Kaohsiung Chang Gung Memorial Hospital, Taiwan; Center for Mitochondrial Research and Medicine, Kaohsiung Chang Gung Memorial Hospital, Taiwan.
⁵ Institute of Physical Education, Health & Leisure Studies, National Cheng Kung University, Taiwan. Electronic address: andytsai@mail.ncku.edu.tw.

PMID: 40602732
DOI: 10.1016/j.exger.2025.112820

Abstract

Anxiety is associated with significant functional impairments and diminished mental health and quality of life in older adults. According to stress reduction theory, engaging in physical activity in natural settings may play a critical role in alleviating anxiety among older populations. This study aimed to examine the effects of green exercise under different levels of green view index (GVI) on older adults' psychophysiological responses, including pupil size, anxiety, perceived exertion, and environmental preference. A total of 90 older adults aged 50-75 years were recruited and successfully completed the experiment. Participants were assigned to one of three natural cycling environments, each defined by a different level of GVI: high (60 %), medium (35 %), and low (0 %, control group). The selected environment was a tree-lined path within an urban park featuring lawns, vegetation, and shaded areas. The control group cycled while facing gray urban buildings. All participants completed a single, 20-min moderate-intensity cycling session as the intervention. Pupil size was measured using Tobii Pro Glasses 2, a wearable eye-tracking device operating at 100 Hz. The results showed that the HGVI and MGVI received the smaller pupil size and higher favorable preferences from older adult participants than those from control group. Both excessively high and low levels of GVI in natural environments tend to produce a trade-off between reductions in anxiety and increases in perceived physical exertion. Furthermore, environments with medium to high levels of visible greenery (GVI ≥ 35 %) significantly enhance the psychophysiological benefits of exercise in older adults. Exercise environments with MGVI are considered optimal in balancing anxiety reduction with adequate physical exertion, making them ideal targets for age-friendly urban design.

Keywords: Anxiety reduction; Green exercise; Green view index; Perceived exertion; Pupil size.