High Intensity Interval Training Is Associated With Decreased Negative Affect In Individuals With Anxiety Disorders

INTRODUCTION: Exercise has been shown to reduce negative affect (NA) in people with anxiety. PURPOSE: To investigate associations between 2 heart rate (HR)-derived indices of exercise volume and change scores on NA measures using a novel high intensity interval training (HIIT) protocol administered at home with remote coaching in people with anxiety disorders. METHODS: In a pilot study, eleven insufficient active people (Chester Step Test estimated baseline VO2peak 33.18±5.89 ml·kg-1·min-1) diagnosed with an anxiety disorder and State-Trait Anxiety Inventory (STAI) score > 44 performed a 6-week, 4 days/week HIIT program using a stepper machine. Each session included 8 to 12-minutes of HIIT (20/40 sec ratio - target HR 85% of estimated maximal HR) and data were uploaded to a cloud server. Questionnaires were collected at baseline, 3, and 6 wks. Continuous HR was recorded, producing an HR curve. Amount of exercise was computed as the sum (AUCS) and average (AUCA) area under these HR curves above the baseline resting HR. For each combination of the 6 clinical outcomes (STAI, Depression, Anxiety, and Stress Scales and Quality of Life Questionnaires) and 2 AUC measures, nonparametric correlations were calculated and adjusted by Bonferroni correction for multiple comparisons (significant if p<.0014). Correlations were calculated for change scores from baseline to wk 6, baseline to wk 3, and wk 3 to 6. RESULTS: 2 males and 9 females aged 25.05±2.82 years, BMI 23.95±4.27 completed the study. Adherence was 88%. AUCS and AUCA in the first 3 wks were negatively associated with wk 3-baseline change in state anxiety (r = -.95, p<.0001 and r = -.84, p<.0014 respectively), indicating that patients with greater volume of exercise experienced greater state anxiety reductions over the same period. AUCS and AUCA variance explained 90.25% and 70.56% of the variance in state anxiety change over the same period, respectively. Correlations between AUC indices and other NA measures also were negative but nonsignificant, possibly due to small sample size. CONCLUSIONS: AUC indices were significantly and inversely associated with changes in state anxiety from baseline to wk 3 and the remaining outcomes showed nonsignificant associations in the predicted directions. HIIT could be a promising intervention to reduce NA in anxiety disorders.