Affective response and arousal (alertness)
bipolar
HYPOXIC
The Feeling Scale (FS), a bipolar scale comprising 11 items ranging from − 5 (very bad) to + 5 (very good), developed, and validated by Hardy and Rejeski was used to measure affective response. The positive numbers represent pleasure, the negative numbers represent displeasure, and zero represents a neutral affective valence. Perceived activation (arousal) was measured using the Felt Arousal Scale (FAS) consisting of 6 items ranging from 1 (low arousal) to 6 (high arousal). During the familiarization session, the participants were acquainted with the concept of affective response, arousal, and how to report their perceptual responses while performing the endurance task under the hypoxic condition (at every 3 min during the task and at exhaustion). All these responses were used to calculate average FS and FAS responses for each experimental condition and used for statistical analyses. The Circumplex Model of Affect proposed by Russell et al. (1980), was used to analyze the perceptual responses since it has been reported to be more consistent with many current findings from behavioral, cognitive neuroscience, neuroimaging, and developmental studies of affect. This model contains two interrelated neurophysiological systems including valence (a pleasure-displeasure continuum) and arousal or alertness (an activation-deactivation continuum). Accordingly, each emotion is considered a linear combination of valence and arousal [