Temperature and lighting level are relatively important parameters of indoor environment in a university classroom because they affect students' learning performance. Previous research primarily focused on analyzing students' learning performance, ignoring the learning process involved and the impact of physiological reactions to their learning environment. This study investigates the learning process as well as the influence of students' sensations/comfort and physiological responses. Experiments were carried out in a university classroom with 17 students performing cognitive tests while wearing an EEG headset and an ECG wristband at different temperatures (20-23°C, 23-26°C, 26-29°C) and lighting levels (100-300 lux, 300-600 lux,600-900 lux). The results showed brighter light improved concentration, while neutral temperature was important for working memory, and a comfortable environment and emotional state were important in increasing motivation for better learning performance. The findings can be used to develop an IEQ management plan that will contribute to improve the learning environment.