The relationship between exercise intensity and affective responses demystified: To crack the 40-year-old nut, replace the 40-year-old nutcracker!

Background: A causal chain linking exercise intensity, affective responses (e.g., pleasure-displeasure), and adherence has long been suspected as a contributor to the public health problem of physical inactivity. However, progress in the investigation of this model has been limited, mainly due to inconsistent findings on the first link between exercise intensity and affective responses. Purpose: The purpose was to reexamine the intensity-affect relationship using a new methodological platform. Methods: Thirty young adults (14 women and 16 men) participated in 15-min treadmill exercise sessions below, at, and above their ventilatory threshold. The innovative elements were the following: (a) Affect was assessed in terms of the dimensions of the circumplex model; (b) assessments were made repeatedly during and after exercise; (c) patterns of interindividual variability were examined; (d) intensity was determined in relation to the ventilatory threshold; and (e) hypotheses derived from the dual-mode model were tested. Results: Intensity did not influence the positive changes from pre- to post-exercise, but it did influence the responses during exercise, with the intensity that exceeded the ventilatory threshold eliciting significant and relatively homogeneous decreases in pleasure. Conclusions: Exceeding the intensity of the ventilatory threshold appears to reduce pleasure, an effect that could negatively impact adherence.