Psychological and Behavioral Responses to Interval and Continuous Exercise

Does sex mediate the affective response to high intensity interval exercise?

High intensity interval exercise (HIIE) is identified as an alternative to moderate intensity continuous exercise (MICE) due to its similar effects on outcomes including maximal oxygen uptake and glycemic control. Nevertheless, its widespread implementation in adults is questioned because acute HIIE elicits more aversive responses (negative affective valence) than MICE which may make it impractical to perform long-term. Differences in muscle mass, fiber type, and substrate utilization exist between men and women that alter physiological responses which may cause differences in affective valence, yet the effect of sex on this outcome is unresolved. This study compared changes in affective valence between active men and women (mean age = 24.0 ± 4.8 yr) performing HIIE and sprint interval exercise (SIE) on a cycle ergometer. Affect (+5 to -5), rating of perceived exertion (RPE 1-10), and blood lactate concentration (BLa) were measured before and throughout exercise, and enjoyment was assessed post-exercise. Results showed that women exhibit more positive affect (p < .05) during HIIE and SIE than men (0.6-1.8 units higher values). In addition, women exhibited lower BLa (p = .003) than men during SIE (11.8 ± 2.4 mM vs. 14.9 ± 3.1 mM). In contrast, there was no effect of sex on RPE (p = .32 and p = .54) or enjoyment (p = .24 and p = .37) in response to HIIE or SIE. Practitioners should consider the sex of their clients when assessing change in affective valence induced by interval-based exercise.

Interval Training Improves Depressive Symptoms But Not Anxious Symptoms in Healthy Women

Background: Despite important advances in the relationship between exercise and mood disorders, especially regarding moderate-intensity continuous training, there is a lack of information about the chronic effects of interval training protocols. We compared the effects of two different interval training protocols [sprint interval training (SIT) and high-intensity interval training (HIIT)] on depressive and anxious symptoms in healthy women. Methods: Thirty-six women were randomly allocated to HIIT (n = 18) or SIT (n = 18) groups and performed 24 training sessions over 8 weeks (thrice a week). Levels of state-trait anxiety and depressive symptoms were evaluated using State-Trait Anxiety Inventory and Beck Depression Inventory, respectively, before and after training intervention. Results: Two-way analysis of variance (ANOVA) did not reveal a significant effect of time (p > 0.05), group intervention (p > 0.05), or time × group interaction (p > 0.05) on state-trait anxiety; however, two-way ANOVA showed a significant effect of time on depressive symptoms (p = 0.025) but not group effect (p = 0.548) or time × group interaction (p = 0.373). Depressive symptoms of the participants in both HIIT and SIT groups were reduced from baseline, (Δ_HIIT) -17.5 ± 27.9% and (Δ_SIT) -28.6 ± 47.5%, respectively. Conclusion: HIIT and SIT groups similarly improved depressive symptoms but not anxiety levels in healthy and physically active young adult women.