Author(s): KINGHORN, D., PAVAL, D.R., GALLAGHER, I.J., VOLLAARD, N.B.J., Institution: THE UNIVERSITY OF STIRLING, Country: UNITED KINGDOM, Abstract-ID: 2157

INTRODUCTION:
Affective valence (AV; i.e., feelings of pleasure (positive affect) or displeasure (negative affect)) can be modified by exercise. Whether exercise makes someone feel ‘good’ or ‘bad’ may influence exercise enjoyment, and subsequently the uptake of, and adherence to, exercise routines. The dual-mode theory (DMT; Ekkekakis et al., 2008) proposes a homogenous increase in affective valence during exercise at intensities below the ventilatory threshold (VT), and a decreasing level of pleasure above the VT. This has led to an increase in studies investigating the effect of exercise at intensities prescribed relative to the VT on AV. The aim of the present study was to analyse the relationship between exercise intensity relative to the VT and the change in affective valence during exercise.
METHODS:
A systematic review and meta-analysis (PROSPERO ID: CRD42022331507) was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The databases PubMed, Web of Science, Scopus and PsycInfo were searched up to August 2022 for the 4 possible combinations of the search terms “affective valence” OR “feeling scale” AND “ventilatory threshold” OR “lactate threshold”. Studies were eligible if they investigated affective responses to exercise in apparently healthy adults with intensities set relative to the VT or lactate threshold (LT). Bayesian meta-analysis using linear and non-linear modelling was conducted to examine the relationship between exercise intensity relative to the VT and the greatest change in affective valence from baseline (pre-exercise) to any time points during exercise. Studies missing baseline affect data and trials implementing interventions in addition to exercise were excluded.
RESULTS:
The search yielded 18 trials, involving n=533 participants, and exercise intensities equivalent to 80-110% of VT. Four of eight trials at intensities ranging from 80% to 96% of VT, four of five trials at 100% of VT, and all trials at intensities >100% of VT resulted in decreases in affective valence. Meta-regression analysis demonstrated a considerable effect of exercise intensity (effect size=1.41, 95% highest density interval (HDI): 0.41-2.39). No meaningful moderating effects of age, sex, BMI, and VO2max were observed at 95% HDI. The DMT proposes a non-linear relation between exercise intensity and the change in AV during exercise, but over the (limited) range of intensities in the available trials, the best fitting non-linear model was not superior to a linear model.
CONCLUSION:
Although the analysis provides some support for the role of the VT as a turning point for changes in AV during exercise, there was no evidence for a homogenous positive response at intensities at or below the VT. Future research should identify factors explaining the variance in the change in affective valence during exercise at intensities at or below the VT.