Effect of a Cool Classroom Microclimate on Symbolic Indexes of Cardiac Autonomic Control and Cognitive Performances in Undergraduate Students

The effect of classroom temperature reduction on cognitive performance and cardiac autonomic control were assessed in 12 healthy undergraduate students during a 2-hour lasting lecture. In all subjects ECG was continuously recorded by a portable device when classroom temperature was “neutral” (22.4±0.1
^°
C, Day1) and “cool” (18.4
^°
C±0.3
^°
C, Day2). Symbolic analysis of RR variability provided the percentage of three heart period sequences with no significant change in RR interval (0V%) and with two significant variations (2UV%), reflecting cardiac sympathetic and vagal modulation, respectively. Students' cognitive performance was assessed at the end of each lecture by the Cambridge Brain Sciences cognitive evaluation tool. In Day2 the 0V% was greater and 2UV
^%
was lower compared to Day1. Cognitive performance rated better in Day2 compared to Day1. Students' cognitive performance was improved and their cardiac sympathetic modulation was enhanced when the lecture was performed in a cooler environment.