Effects of outdoor activity intensities on college students’ indoor thermal perception and cognitive performance

Using neurobehavioral tests, electroencephalogram signal monitoring, and questionnaire surveys, we recruited 158 healthy college students to explore the effects of light, moderate, and vigorous intensity activities on indoor thermal perception, cognitive performance, physical health and emotions in a hot outdoor environment. Our results suggested four principal outcomes: (1) compared with the pre-exercise, reduction in mean thermal sensation gradually increased while reduction in mean thermal comfort decreased as the proportion of thermal symptoms increased by 17.0%, 48.0%, and 76.0% during light to vigorous activity; (2) when the Universal Thermal Climate Index changed between 23.0 °C and 49.2 °C, moderate intensity activity can maximize the cognitive performance of college students indoors; (3) the skin temperature measured at the upper arm increased at higher intensity activity. Systolic pressure, diastolic pressure, and eardrum temperature significantly increased after engaging in different intensity activities. Heart rate showed a significant increase after moderate to vigorous intensity, while oxyhemoglobin saturation decreased following vigorous intensity; and (4) when returning indoors after engaging in outdoor activities, frontal brain asymmetry increased by 0.17 as positive emotions enhanced; but after vigorous intensity, the frontal lobe asymmetry decreased by 0.11 as negative emotions increased. Our results could provide fundamental guidance to improve the indoor learning efficiency and thermal comfort of college students. • Effects of outdoor activities on cognitive performance indoors were studied in Xi'an, China. • Thermal comfort vote was decreased by 0.44, 0.81, and 1.20 from light to vigorous intensity. • Moderate intensity activity increased indoor cognitive performances of college students. • Positive emotions were enhanced when returning indoors after light and moderate intensity.