The efficacy of aerobic exercise and resistance training as transdiagnostic interventions for anxiety-related disorders and constructs: A randomized controlled trial
Introduction
Anxiety-related disorders (including anxiety disorders, obsessive-compulsive disorder, and posttraumatic stress disorder) are highly prevalent and comorbid, affecting approximately 28.8% of individuals over their lifetime (Kessler et al., 2005). Although these disorders share superficial similarities, such as overlap in diagnostic criteria (Barlow, 2014), evidence suggests that they also share common etiology (Bienvenu, Hettema, Neale, Prescott, & Kendler, 2007; Brown and Naragon-Gainey, 2013, Carleton, 2016, Hettema, 2006), latent structure and higher dimensions (Brown, 2007; Paulus, Talkovsky, Heggeness, & Norton, 2015), and response to treatment (Hadjistavropoulos et al., 2014, Norton and Barrera, 2012). These shared factors have fostered the development of transdiagnostic treatments that can effectively target a relatively wide array of anxiety-related psychopathological concerns and that can be widely and efficiently distributed to the individuals in need of treatment.
In recent years, there has been increasing empirical support for the role of exercise as a legitimate standalone or adjuvant treatment for a variety of mental health concerns (Asmundson et al., 2013). Particularly, specific types of exercise, such as aerobic exercise and resistance training, have shown promise for social anxiety disorder, panic disorder, generalized anxiety disorder, obsessive-compulsive disorder, and posttraumatic stress disorder (Broocks et al., 1998, Fetzner and Asmundson, 2015; Herring, Jacob, Suveg, & O’Connor, 2011; Jazaieri, Goldin, Werner, Ziv, & Gross, 2012; Powers et al., 2015; Rector, Richter, Lerman, & Regev, 2015). Potential differences in the efficacy of distinct exercise paradigms have seldom been systemically evaluated using robust empirical methodology in the form of randomized controlled trials.
The effects of exercise on constructs thought to underlie and maintain anxiety-related disorders have been studied to varied and limited extent, including anxiety sensitivity (i.e., fear of anxiety-related sensations based on negative or catastrophic beliefs regarding their consequences; Reiss & McNally, 1985; Wheaton, Deacon, McGrath, Berman, & Abramowitz, 2012), distress tolerance (i.e., the ability to tolerate emotional distress; Leyro, Zvolensky, & Bernstein, 2010; Simons & Gaher, 2005), and intolerance of uncertainty (i.e., the inability to withstand ambiguous or uncertain situations; Carleton, 2012; Laugesen, Dugas, & Bukowski, 2003; McEvoy & Mahoney, 2011). Aerobic exercise appears to reduce anxiety sensitivity (e.g., Fetzner and Asmundson, 2015, LeBouthillier and Asmundson, 2015, Smits et al., 2008), but only one study to date has examined the effects of resistance training (Broman-Fulks, Kelso, & Zawilinski, 2015). Limited evidence suggests that distress tolerance and intolerance of uncertainty are not amenable to change after acute exercise (Broman-Fulks et al., 2015, LeBouthillier and Asmundson, 2015), but the effect of longer exercise interventions remains untested. Greater research on the effects of exercise on these constructs could bolster exercise as a legitimate intervention for anxiety-related disorders and help elucidate mechanisms of action.
Likewise, little is known regarding factors that may affect the efficacy of exercise for anxiety-related psychopathology. Evidence suggests a role of physical fitness in predicting the effectiveness of these interventions: While individuals with posttraumatic stress disorder generally benefit from aerobic exercise, those with lower cardiorespiratory fitness experience relatively greater reductions in symptoms (LeBouthillier & Asmundson, 2015). Sedentary individuals also benefit more from acute exercise than active individuals (Ensari, Greenlee, Motl, & Petruzzello, 2015). Enjoyment of exercise is another potentially important factor that is seldom investigated. Individuals have greater enhancements in mood states following their most preferred compared to their least preferred exercise modality (Lane, Jackson, & Terry, 2005) and engaging in exercise that increases self-efficacy appears to effect greater reductions in anxiety (Bodin & Martinsen, 2004).
Despite the flourishing and diverse nature of research on the mental health benefits of exercise, integrative and controlled research on the relationship between exercise and anxiety-related disorders and constructs is lacking. Consequently, the purposes of the current trial were to: (1) quantify the effects of aerobic exercise and resistance training on anxiety-related disorder status, symptoms, and constructs, (2) evaluate whether both modalities of exercise are equivalent, and (3) to determine whether exercise enjoyment and physical fitness are associated with symptom reduction. We tested three hypotheses, namely that (1) aerobic exercise and resistance training would both be efficacious in improving disorder status, disorder-specific symptoms, and related construct (i.e., general psychological distress, depression, anxiety, stress, anxiety sensitivity, distress tolerance, intolerance of uncertainty) when compared to a waitlist control; (2) the efficacy of both types of exercise would be generally equivalent in reducing disorder-specific symptoms and related constructs, and (3) greater enjoyment of the assigned exercise condition and lower fitness would predict the magnitude of reductions in disorder-specific symptoms and related constructs. The present trial also addressed limitations in current literature by using a transdiagnostic approach to study a mixed sample of individuals with anxiety-related disorders, quantifying changes in other important anxiety-related constructs, and utilizing a randomized controlled trial design.
Section snippets
Participants
Ethical approval for the trial was obtained from the University of Regina Research Ethics Board. Data were from 48 community individuals diagnosed with an anxiety-related disorder (see below). Participants were eligible for the trial if they were between 18 and 65 years of age, resided in the Regina, Saskatchewan area, reported fewer than 150 min of moderate to vigorous exercise weekly, could safely engage in exercise, were not engaged in empirically supported therapy for anxiety (e.g.,
Descriptive statistics
Participant demographics at pre-intervention by trial group are presented in Table 1. Scores for disorder-specific and transdiagnostic outcomes measures, as well as exercise and fitness-related measures at baseline are presented in Table 2. Individuals enrolled in the trial were primary female, White, single, married or cohabiting, and employed full time. In all trial groups, participants were most likely to meet criteria for social anxiety disorder or generalized anxiety disorder.
An overview
Discussion
The primary purpose of the present trial was to determine and compare the efficacy of two types of exercise in reducing anxiety-related disorder symptoms and constructs. Additionally, a secondary purpose of the present trial was to determine whether individual factors, namely physical fitness and enjoyment of exercise, were associated with greater benefits from exercise. Taken together, the primary findings of the present trial provide evidence for the role of exercise in reducing
Conclusions
The present trial is the first to investigate the efficacy of different types of exercise on anxiety-related disorders and related constructs and using a randomized controlled design. Both aerobic exercise and resistance training appear to be efficacious in effecting improvements in anxiety-related disorder symptoms and related constructs. While exercise enjoyment does not appear to predict the effectiveness of exercise, lower physical fitness is associated with greater reductions in specific
Conflicts of interest
The authors declare no conflicts of interest.
Acknowledgments
Daniel M. LeBouthillier is supported by a Canadian Institutes of Health Research Doctoral Research Award (FRN: 146270). Gordon J. G. Asmundson was supported, in part, by the University of Regina President’s Chair for Academic Excellence in Adult Mental Health Research.
The authors would like to thank Dr. Darren Candow and the Aging Muscle and Bone Health Laboratory at the University of Regina for graciously providing exercise training amenities to participants during the trial.
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