Effekte von Intervalltraining versus dem Training nach der Dauermethode auf dem Laufband bei COPD-Patienten

Pulmonary rehabilitation (PR) is a multidisciplinary therapy concept which leads to improvements of quality of life and physical performance as well as alleviation of disease sequelae in patients with COPD on the highest level of evidence (Ries et al. 2007, GOLD Report 2021). Based on a study with end-stage COPD patients, it was shown that ergometer training with intensive interval training (IT) is superior to moderate endurance training (DM) in terms of subjectively perceived breathlessness (measured by the Borg scale) as well as the number of unplanned breaks (Gloeckl et al. 2012). The aim of this study was to compare the effects of these both types of training on a treadmill due to the potential greater relevance to patients' daily life activities. This study was a prospective, randomized, controlled intervention study without blinding. During a 3-week inpatient pneumological rehabilitation (PR) at the Schön Klinik Berchtesgadener Land, 43 patients with COPD GOLD stage III and IV (Age: 64 ± 9 years, FEV1: 37 ± 14 % of target, 6-MWT: 381 ± 112 meters) were randomized 1:1 into one of two training groups. All subjects underwent the same multimodal rehabilitation program consisting of medical monitoring, respiratory physiotherapy, psychosocial counseling, education, and exercise training (MTT) including standardized strength training (5x/week). The only difference in the content of the rehabilitation program was seen in the endurance training, which was either a moderate endurance training (DM) or an intensive interval training (IT). The individual submaximal performance of each patient was determined using the 6-minute walk test (6-MWT). Twenty patients performed treadmill walking training (5x/week) at an intensity of 60% of their 6-MWT walking speed as moderate DM, and 22 patients performed an intensive IT at 120%, there was one drop-out in the DM before the start of the first training session. Training duration was progressively increased during PR from 10 minutes (1x/day) to 32 minutes (2x/day). During the course of training, the patient's perceived dyspnea and leg fatigue were assessed using the Borg scale scores. To assess physical performance, the 6-MWT was performed at the beginning and end of the PR. Changes in leg strength were documented using the CRT and strength measurement of leg flexor and extensor. Quality of life was also assessed both before and after PR using questionnaires such as the SF-36, the CRQ, and the HADS. During the individual training sessions on the treadmill, continuous monitoring of heart rate (HR) and oxygen saturation (SpO2) was performed. Furthermore, any unplanned breaks required during the endurance training were recorded. Perceived breathlessness, measured by the Borg scale scores from 0-10, was during all training sessions in average significantly lower in the IT group than in the DM group, with a group difference of 0.5 points (IT: 3.7 ± 1.0 points vs. 4.2 ± 1.2 points) and decreased from the beginning of the intervention (average of first and second training session) to the end of the intervention (average of last and penultimate training session) slightly more in the IT than in the DM group (IT: -1.0 (-1.7 to -0.4) points vs. DM: -0.3 (-1.4 to 0.3) points). This improvement turned out to be highly statistically significant (p<0.01) in IT as well as clinically relevant with no significant between-group difference of Δ 0.8 points to DM. The improvement in 6-MWT (IT: +45.0 (37.7 to 69.4) meters vs. DM: +40.0 (26.6 to 58.4) meters) was shown to be highly significant (p<0.01) and clinically relevant in both study groups with no significant between-group difference of Δ 5.0. In the 5-CRT (5 Chair-Rise-Test), all study subjects were able to improve their 5 repetitions in the stand-up test statistically highly significant (p<0.01) by a mean of -2.1 seconds (IT: -2.3 (-4.2 to -0.7) seconds vs. DM: -2.1 (-3.4 to -0.6) seconds, p<0.01) with no significant group difference of Δ 0.2. The strength measurement of leg extensor and flexor by a dynamometer showed a significant increase in muscle strength (p<0.05) in each case in the IT group as a result of the intervention (leg extensor: +1.0 (0.6 to 3.2) % predicted, leg flexor: +3.0 (1.9 to 4.1) % predicted) with no significant group difference to the DM. In the DM group, the increase in muscle strength over the same period was +2.0 (0.9 to 2.6) % predicted for leg extensors and +2.0 (0.4 to 5.6) % predicted for leg flexors, and was not statistically significant. Subjectively perceived leg fatigue after Borg decreased similarly from the beginning to the end of the intervention in both groups (IT: -0.5 (-1.5 to -0.1) points vs. DM: -0.5 (-1.0 to 0.6) points). This improvement was shown to be statistically significant in the IT group (p<0.05). The mean value of Borg leg fatigue during all training sessions was clearly lower in the IT group than in the DM group with a group difference of 0.7 points (IT: 2.2 ± 1.3 points vs. 2.9 ± 1.5 points). By using 3 questionnaires on health-related quality of life, it could be shown that the study subjects tended to rate their quality of life better after completion of the 3-week PR than at the beginning. In some cases, significant improvements could even be detected. The DM group experienced a highly significant greater number of unscheduled breaks during training than the IT group (DM: 6.7 ± 15.0 breaks vs. IT: 0.6 ± 1.4 breaks, p<0.01). No exercise-related complications or other adverse side effects were observed. In conclusion, it was shown that subjects in the interval training group had to take less unplanned breaks. In terms of physical performance, muscle strength in the legs and health-related quality of life, both moderate endurance training and intensive interval training appear to be comparably effective training methods on the treadmill. Subjectively perceived breathlessness and leg fatigue showed significant decreases in IT during PR. If this assumption is confirmed in follow-up studies with a larger number of cases, in the future greater focus could be placed on treadmill training in pulmonary rehabilitation of patients with COPD, using the interval method.