Effects of different classroom temperatures on cardiac autonomic control and cognitive performances in undergraduate students

Abstract

Objective: Indoor microclimate may affect students’ wellbeing, cardiac autonomic control and cognitive performance with potential impact on learning capabilities. To assess the effects of classroom temperature variations on the autonomic profile and students’ cognitive capabilities. Approach: Twenty students attending Humanitas University School, (14M, age 21 ± 3 years) underwent a single-lead ECG continuous recording by a portable device during a 2 h lecture when classroom temperature was set ‘neutral’ (20 °C–22 °C, Day 1) and when classroom temperature was set to 24 °C–26 °C (Day 2). ECGs were sent by telemetry to a server for off-line analysis. Spectral analysis of RR variability provided indices of cardiac sympathetic (LFnu), vagal (HF, HFnu) and cardiac sympatho-vagal modulation (LF/HF). Symbolic analysis of RR variability provided the percentage of sequences of three heart periods with no significant change in RR interval (0V%) and with two significant variations (2V%) reflecting cardiac sympathetic and vagal modulation, respectively. Students’ cognitive performance (memory, verbal comprehension and reasoning) was assessed at the end of each lecture using the Cambridge Brain Sciences cognitive evaluation tool. Main results: Classroom temperature and CO2 were assessed every 5 min. Classroom temperatures were 22.4 °C ± 0.1 °C (Day 1) and 26.2 °C ± 0.1 °C (Day 2). Student’s thermal comfort was lower during Day 2 compared to Day 1. HR, LF/HF and 0V% were greater during Day 2 (79.5 ± 12.1 bpm, 6.9 ± 7.1 and 32.8% ± 10.3%) than during Day 1 (72.6 ± 10.8 bpm, 3.4 ± 3.7, 21.4% ± 9.2%). Conversely, 2V% was lower during Day 2 (23.1% ± 8.1%) than during Day 1 (32.3% ± 11.4%). Short-term memory, verbal ability and the overall cognitive C-score scores were lower during Day 2 (10.3 ± 0.3; 8.1 ± 1.2 and 10.9 ± 2.0) compared to Day 1 (11.7 ± 2.1; 10.7 ± 1.7 and 12.6 ± 1.8). Significance: During Day 2, a shift of the cardiac autonomic control towards a sympathetic predominance was observed compared to Day 1, in the presence of greater thermal discomfort. Furthermore, during Day 2 reduced cognitive performances were found.

Classrooms' indoor environmental conditions affecting the academic achievement of students and teachers in higher education: A systematic literature review

“…Thermal discomfort, caused by high or low temperatures, affects students' cognitive performance 22,23,31,33,34 . Barbic et al 31 observed a decrease of as much as 24% when students experienced thermal discomfort due to high temperature. However, not all thermal discomfort sensations lead to a deterioration of cognitive performance, 27 and the effect is most likely task dependent.…”

“…As observed for thermal conditions, the extent of this effect was also task‐dependent. To quantify students' short‐term academic performance, seven of the 11 studies used standard cognitive performance tests 22,23,26‐28,31,33,34 . Castro‐Martínez et al 42 used a different method to quantify students' short‐term academic performance.…”

Thermal Comfort in School Classes in the Era of Global Warming: A Prospective Multicenter Study

“…9,10,[30][31][32] These existing questionnaires were analyzed and we designed our questionnaire for the current survey ( Table 1). The authors intended to conduct the survey at high schools and to adjust the questionnaire to an adolescents' level (age [15][16][17]. This one-page questionnaire consisted of 5 preliminary yes/no questions to assess the physiological and neuropsychological status of a participant at the moment of the survey, outdoor and indoor thermal sensations scales, and comfort level scale after 15 minutes in class (adaptation process).…”

“…14,15 Coming to the more recent times, several schoolbased thermal comfort studies were published from 2009 to 2019. [16][17][18][19] These studies were location-specific and their results cannot be generalized; however, the authors agreed that thermal discomfort reduces the attention index and general cognitive performances in adolescents. This general topic of thermal comfort is connected with various specific topics such as agerelated thermoregulatory differences, 20,21 the effect of clothing, 16,[22][23][24] and gender differences.…”

“…Specifically for schools, it was demonstrated that thermal conditions in classes were not adequate already during the pre‐global warming era 14,15 . Coming to the more recent times, several school‐based thermal comfort studies were published from 2009 to 2019 16‐19 . These studies were location‐specific and their results cannot be generalized; however, the authors agreed that thermal discomfort reduces the attention index and general cognitive performances in adolescents.…”