Subjective sleepiness and relaxation were anti-correlated pre-intervention, demonstrating they are distinct constructs, though this negative correlation was inconsistent post-intervention.
Meta-Analysis
Subjective sleepiness and relaxation are distinct mental constructs that are anti-correlated pre-intervention, though this relationship may change post-intervention.
Human well-being and functioning depend on two fundamental mental states: Relaxation and sleepiness. Relaxation and sleepiness are both assumed to be states of low physiological arousal and negatively correlated. However, it is still unclear how consistent this negative relationship is across different settings and whether it changes before and after an intervention. Here we investigated this intricate relationship between subjective momentary sleepiness and relaxation states by meta-analytically analyzing several data sets from studies using the Relaxation State Questionnaire. We discovered that subjective sleepiness and relaxation were in fact anti-correlated pre-intervention. This anti-correlation provides a quantitative dissociation between sleepiness and relaxation. Thus, even though sleepiness and relaxation both implicate a low arousal level, the two mental states are subjectively experienced in a qualitatively different fashion, and thus reflect distinct underlying constructs. For the post-intervention relationship, this negative correlation could not be consistently found. This indicates that there are aspects of the experimental setting or intervention that introduce changes in the dynamics of the relationship of the two constructs.
Steghaus et al. (Mon,) conducted a meta-analysis in Low physiological arousal. Subjective sleepiness and relaxation were anti-correlated pre-intervention, demonstrating they are distinct constructs, though this negative correlation was inconsistent post-intervention.