An Investigation Into The Anxiolytic Effects Of Hand-squeezing Exercise And The Role Of Potential Moderators

Muscle contractions using a squeeze ball may acutely improve an individual’s state anxiety, however, that this effect may depend upon baseline levels. Most of this work is completed in surgery/medical procedures and it has been suggested that this could be working through a distraction effect. However, the methods of hand squeezing described in the literature are not clear and there is a lack of standardization for contraction intensity. PURPOSE: To determine: 1) the effect isometric handgrip exercise on state anxiety and exercise affect, and 2) if this effect depended on the baseline anxiety level. METHODS: 50 participants (22 years, 22 men) completed a single visit. Participants completed questionnaires about anxiety, worry, and exercise affect. Participants were then randomly assigned into either a handgrip exercise group (HG, n = 21) or time-matched non-exercise control group (CON, n = 29). HG performed 3 sets of maximal isometric handgrip exercise with 1-minute rest between sets for each hand (9 contractions total per hand). Following the initial 5 minutes (HG or rest), participants sat quietly for an additional 5 minutes of rest before completing a questionnaire on state anxiety and exercise affect. RESULTS: Baseline trait anxiety and worry for CON was 39.1 (SD 9) and 54.2 (SD 13) units and the HG group was 42.3 (SD 10) and 50.8 (SD 14) units. There was no evidence that state anxiety differed between groups (adjusted for pre-test: CON: 32.5 vs. HG: 32.1 units) at the post-test [p = 0.830, -0.41 (95% CI: -4.3, 3.4)] units. The impact of HG on state anxiety did not depend upon baseline levels of trait anxiety (p = 0.255 for group * trait) or worry (p = 0.11 for group*worry). Positive well-being (CON: 21.2 vs. HG: 20.1 units, p = 0.539), psychological distress (CON: 5.8 vs. HG: 6.1 units, p = 0.233), and fatigue (CON: 11 vs. HG: 12.6 units, p = 0.979) did not differ at the post-test between groups (adjusting for pre-test). CONCLUSIONS: We did not find anxiolytic effects or differences in exercise affect following maximal hand-squeezing. However, we are not able to rule out that the anxiolytic effect depends upon baseline levels of trait anxiety and worry (i.e. hand squeezing might be beneficial in those with high levels of baseline worry). Additional observations are necessary in order to better understand this possible moderating effect.