A new randomized trial shows that short bursts of supervised high-intensity exercise may retrain the brain’s fear response to bodily sensations, offering a scalable and engaging new therapeutic pathway for people with panic disorder.
Study: Brief intermittent intense exercise as interoceptive exposure for panic disorder: a randomized controlled clinical trial. Image credit: Pixel-Shot/Shutterstock.com
Interoceptive exposure (IE) is a key component of cognitive-behavioral therapy (CBT) for panic disorder (PD). However, current modes of IE tend to be monotonous and unattractive to patients. A recent study published in the journal Frontiers in Psychiatry directly compared intense physical exercise as a stand-alone IE intervention with relaxation training (RT) in patients with PD, testing exercise as a targeted IE strategy.
Why triggering symptoms can reduce panic responses
Panic attacks (PA) are sudden episodes of intense fear that arise in association with physiological changes like a speeded-up heart rate or dizziness, resulting from autonomic arousal. With repeated PA, as in panic disorder (PD), patients tend to interpret these bodily cues as threatening. They first become wary of them and then anxious and fearful.
This results in PD patients becoming abnormally sensitive to their internal sensations and tending to overestimate their severity and consequences. For example, false feedback on the heart rate can make PD patients believe they have tachycardia. Despite the absence of any symptoms, they become anxious and panicky. Similarly, PD often impairs the ability to accurately judge one’s bodily cues, like assessing the degree of exertion at the anaerobic threshold during ergospirometry tests.
Such individuals often try to avoid PA by avoiding physical activity and becoming sedentary. One hypothesis is that in PD patients, the hyperactive autonomic sensations become learned triggers for feelings of threat and anxiety, an interoceptive conditioned stimulus.
CBT is an effective treatment for PD, and includes IE as a central component. IE improves PA frequency and severity, and reduces functional impairment due to PD. IE involves the deliberate induction of uncomfortable physical feelings like dyspnea, palpitations, and dizziness. Being similar to PA triggers, these help retrain the brain to tolerate them without distress.
However, typical office-based IE practices, such as spinning in one’s chair to elicit trigger sensations, are often unacceptable to patients or relatively ineffective.
In contrast, brief intermittent intensive exercise (BIE) is perceived as a type of natural and healthy behavior. Thus, it is a more agreeable way to produce interoceptive cues, including a faster heart rate and breathing rate. Since exercise is often perceived as non-threatening, it might offer a faster route to retraining.
Only one prior study examined the role of exercise in PD as part of a standardized CBT intervention. During that study, another primary IE strategy was used, with exercise being an add-on. However, the researchers did not assess PD-specific outcomes.
The current study sought to fill this gap by using a standardized, stand-alone exercise-based IE intervention rather than a full CBT package and comparing it with RT. RT was chosen as a psychological placebo that is accepted as a credible therapy by patients, although it is not considered a first-line treatment for PD, ensuring a valuable comparison.
Randomized trial tests exercise against relaxation therapy
The researchers conducted a two-arm parallel randomized trial of both brief intermittent intensive exercise (BIE) and Jacobson’s RT. The latter involves deep breathing, followed by alternating tensing and relaxing different muscle groups throughout the body.
The study enrolled 102 randomized participants with panic disorder, of whom 72 completed the intervention and follow-up assessments. The mean age was 33 years, and both groups had comparable panic attack frequency and severity at baseline. All participants were free from psychotropic medication for at least 12 weeks before the program, were not meeting moderate physical activity guidelines, had no history or current substance abuse or dependence, and had no cardiovascular risk factors.
The focus on sedentary participants was intended to recruit individuals who might have stronger fear responses to exercise-induced bodily sensations, potentially increasing the sensitivity of the study to detect interoceptive learning effects.
The participants were randomized to BIE or RT. For BIE, they alternated walking with brief 30-second high-intensity jogging or sprint intervals, performed within structured 30-minute sessions that included warm-up, walking intervals, and progressive increases in sprint repetitions over the 12-week program, under supervision. RT participants followed a standardized progressive muscle relaxation protocol conducted three times weekly in 45-minute sessions over 12 weeks.
All patients were put on the same placebo pills. All were assessed using the Panic Agoraphobia Scale (PAS) score at baseline and at 6, 12, and 24 weeks, with an additional assessment performed shortly before treatment initiation. The participants were also assessed for the frequency and severity of panic attacks. In addition, they were evaluated for depression and anxiety using Hamilton Anxiety Rating Scale (HAM-A) and Hamilton Depression Rating Scale (HAM-D) scores.
Exercise program delivers stronger, longer-lasting symptom improvements
Of the 102 randomized participants, 72 completed the full intervention and follow-up period, with only three participants discontinuing after entering the final analysis cohort. The low drop-out rate may reflect the perceived health benefits of the intervention, its intrinsically rewarding nature, and potentially the motivating experience of receiving treatment in a high-performance clinical setting such as the Movement Laboratory of the Orthopedics Institute, as suggested by the study authors.
Changes in PAS
The PAS score improved in both groups over time. However, when group × time interactions were analyzed, the groups showed distinctly different trajectories.
At baseline, the BIE and RT groups had PAS scores of 32.1 and 30.4, respectively. The mean scores decreased in both groups. However, the drop was steeper, with scores of 14.9 and 23.1 by week 12, representing a clinically meaningful reduction in panic severity in the exercise group.
At week 24, the improvement was maintained in the BIE group, with the PAS being 14.2. Conversely, the score rose slightly in the RT group, to 24.7.
PA frequency and severity
Both groups also showed steep decreases in PA frequency and severity at 12 weeks, with a partial rebound at 24 weeks. The rebound was more muted with BIE, most of the improvement being sustained at the 24-week follow-up. This was not the case with RT, corroborating previous studies that suggest short-term benefits only with RT.
Depression and anxiety
Both groups also showed lower HAM-D and HAM-A scores over time. The most significant difference between groups was in depressive symptoms at week 24. BIE was associated with sustained and more marked improvement. Conversely, symptoms showed a relative worsening beyond 12 weeks with RT.
The long-term gains with BIE suggest that new learning occurs, allowing patients to reinterpret bodily cues as non-threatening. This may extend to daily life, reducing overall arousal. Previous research by the same group supports this, indicating durable benefits of office-based IE.
These sedentary patients were reported by the authors not to experience panic attacks during intensive exercise, which is often associated with hyperventilation and breathlessness. A plausible explanation is that exercise-induced metabolic acidosis counteracts hyperventilation-linked respiratory alkalosis, which is known to induce panic. The environment may also have contributed to the feeling of safety.
The study suggests that BIE is a low-cost, scalable, and more engaging IE strategy with greater efficacy and longer-lasting benefits than RT in this cohort. It offers health benefits and is intrinsically rewarding. The outcomes of using BIE as IE in this study agree with the observation that “more intensive IE can maximize clinical gains, particularly in reducing respiratory and overall anxiety indices.”
The findings also directly support the efficacy of exercise-based IE compared to RT in PD specifically, extending prior research in this area, though the results should not be interpreted as demonstrating equivalence to comprehensive CBT programs.
However, the study has some limitations, notably its small, sedentary young-adult sample with low cardiovascular risk, which may limit generalizability to physically active or broader PD populations. The use of placebo pills in both arms might have confounded the analysis. Also, only one trained rater was used to assess PD throughout the study, and diagnoses were not independently verified by multiple evaluators. Future trials could use multiple assessments to ensure a more accurate diagnosis and compare BIE-CBT with standard IE-CBT protocols for PD.
Exercise-based exposure offers scalable panic disorder treatment
The study suggests that while both RT and BIE were beneficial in PD, the BIE program provided intensive IE associated with more effective and sustained reductions in the severity and frequency of PD symptoms. This may offer a feasible and low-cost alternative to current office-based IE procedures, particularly as an adjunct or targeted IE strategy within broader therapeutic frameworks.
“These findings support the incorporation of structured exercise-based IE into PD treatment programs as a low-cost and engaging option.”
Further research is necessary to identify the target population for maximum benefit, and explore the use of exercise-based IE in various therapeutic models for PD.
Intense exercise proves more effective for panic disorder treatment