Anxiety disorders

Compared to the wide range of research on the positive effects of exercise in major depression, anxiety disorders have been less frequently studied. In addition, the clinical diversity of anxiety disorders does not allow to generalize from studies in one specific anxiety disorder to other disor-ders. Changes in the diagnostic criteria further complicate the interpretation of early studies. However, there is no doubt on the possible anxiolytic effects of aerobic exercise training on healthy volunteers (Long and Satvel 1995). In addition, studies on healthy subjects and two case reports (Orwin 1974; Muller and Armstrong 1975) suggest that an acute bout of exercise is anxiolytic as well. In contrast, exercise may induce acute panic attacks (Broocks et al. 1998; Barlow and Craske 1994) or increase subjective anxiety in patients with panic disorder more than in other people. However, there is preliminary evidence that an acute bout of exercise has an antipanic activity in healthy subjects (Stro¨hle et al. 2005) and in patients with panic disorder (Esquivel et al. 2002), and that patients with panic disorder are more vulnerable to experience somatic symptoms after exercise. Numerous meta analyses have been published on the effect of exercise on anxiety (Petruzzello et al. 1991; Long and van Stavel 1995; Guszkowska 2004). However, only two have examined the effects of exercise in subjects with increased anxiety levels. In one meta-analysis, 11 studies have been analyzed reporting trait anxiety for subjects being identified as highly anxious: the mean effect size was 0.47, indicating that relative to control, exercise training resulted in a moderate reduction in anxiety (Petruzzello et al. 1991). The second meta analysis studied the effects of aerobic and anaerobic exercise on depression and anxiety symptomatology in subjects with anxiety scores above the 50th percentile. Eleven randomized studies compared the effects of an exercise training with a wait-list control and analyses revealed an effect size of 0.94. Within these comparisons, the effect size of studies with formal anxiety disorders (n = 7) was 0.99 (Stich 1998). In patients with high trait anxiety or generalized anxiety disorder, aerobic exercise training was superior to strength and mobility exercises (Steptoe et al. 1989) or no treatment and comparable effective as cognitive behavior therapy (McEntee and Halgin 1999). In a mixed patient sample (panic disorder, generalized anxiety disorder or social phobia), a home-based walking program improved the clinical efficacy of a group cognitive behavioral therapy as compared to educational sessions with a focus on healthy eating (Merom et al. 2007). Case reports (Dractu 2001) and two published clinical studies suggest that exercise training may be used thera-peutically in patients with anxiety neurosis (Sexton et al. 1989) and panic disorder (Broocks et al. 1998); Broocks and coworkers compared clomipramine, exercise training and placebo in patients with panic disorder and demon-strated that although clomipramine had a more rapid onset of action, both the active treatments were significantly better than (pill) placebo. In the most recent study of this group, exercise training was not superior to relaxation in panic disorder patients treated with paroxetine or placebo (Wedekind et al. submitted). Preliminary evidence exists, that panic disorder responds to both aerobic and nonaerobic interventions (Martinsen et al. 1989). Posttraumatic stress disorder may also respond to exer-cise training (Manger 2000; Manger and Motta 2005). However, comparable to the situation in agoraphobia, social phobia and specific phobia adequately sized ran-domized controlled clinical trials are necessary to conclude that exercise training is an effective treatment for patients with specific anxiety disorders. At the moment, we have the best evidence for the effectiveness of exercise training in patients with panic disorder, although replication of these results is still missing