Discussion
tachycardia, POTS, anxiety, stroke, diabetes, bodily pain, Thomas, orthostatic tachycardia, orthostatic symptoms
STROKE, DIABETES
Data from this study demonstrated that providing minimal supervision resulted in better improvements in exercise tolerance and symptoms than receiving exercise recommendation or guidance with no supervision. Additionally, data suggested that improved efficacy is likely due to increased likelihood of exercise being performed at the correct dose (frequency, duration, and intensity).In line with previous work, the individuals with POTS recruited in this study were primarily deconditioned and over half were severely deconditioned. Although symptoms for individuals with POTS are caused by a variety of factors, results of this study highlight that an exercise intervention can improve deconditioning with an observed increase in peak VOOne of the limitations of a prior community-based POTS registry study was that it had a 59% dropout rate, and within those dropouts 40% of participants stopped because training was too difficult (59/148 enrolled) and seven continued training, but at a lower intensity [Although the current study did not have a complete resolution of symptoms which 71% of participants reported in the POTS registry community-based study, those in the ET group demonstrated greater improvement in orthostatic symptoms and a greater improvement in bodily pain (SF-36) compared to the SOC group. Although the 3-month exercise training program may not have resulted in a significant change in reported functional ability score or the orthostatic tachycardia with standing, these were trending in the positive direction. With the significantly greater improvement in exercise tolerance based on improvements in peak workload, time in peak workload, and delay in symptom worsening or onset, as well as signs of improved efficiency at submaximal workloads, this suggests better tolerance of activities of daily living. Further, it has recently been proposed that exercise can provide beneficial vascular conditioning [During the exercise test cardiac output was measured at rest, matched workload of 25 W, and anaerobic threshold to assess improvements in cardiac function with the semi-supervised exercise training anticipating both a reduction in tachycardia and improvement in pumping efficiency or stroke volume. Similar to previous work those in the ET group demonstrated a reduction in heart rate at all submaximal workloads and an increase in stroke volume at anaerobic threshold which maintained cardiac output within the ET group [To achieve the level of improvement observed in this study, the data suggests that exercise dose needs to be sufficient. Work by Thomas et al. demonstrated that only 34% of patients with diabetes start a physical activity routine when provided as a recommended treatment for their condition, and of these that start to exercise only 9% of these patients perform the exercise at a sufficient intensity to be effective [Aspects of the implemented semi-supervised ET program utilized in this study are important to highlight for those trying to implement a similar program. First, cardiopulmonary exercise testing followed by a face-to-face consultation with a clinical understanding of condition-specific limitation allowed for a personalized exercise prescription for each participant. At a minimum, it would be beneficial to have all participants complete a staged progressive exercise test/session with heart rate and symptom monitoring while on their normal medication in the gym where training is occurring or as part of the initial exercise consultation if a clinical cardiopulmonary exercise test is not feasible. Second, receiving occasional real-time instruction in a group environment allows participants to gain comfort in knowing how best to train, can ease fears or anxiety about exercising with their health condition or conditions, and provides guidance on when to progress based on how the prior week’s sessions went. This bridges the gap between the exercise consultation and independent training in a more administratively feasible option. Third, the ability to attend supervised sessions virtually or in-person made the program accessible to those who were from out of state and was more convenient for busy working individuals regardless of location. Fourth, prior work evaluating the characteristics of physical activity promotion programs which are effective for causing and maintaining a behavioral change identified that self-monitoring and social connectivity were two features that appeared to improve initiation rates and maintenance of behavior/lifestyle modifications [