Respiratory Muscle Training and Walking Exercise in Women Recovering From COVID-19 Pneumonia (RECOVID-EX)

This was a single-blind, experimental, pretest-posttest intervention study conducted in adult women who had recovered from COVID-19-related pneumonia and continued to experience dyspnea during the post-discharge period. Participants were recruited from routine post-discharge follow-up settings and were informed about the study procedures before participation. Written informed consent was obtained from all participants before any study-related procedures were performed.

Before the start of the intervention period, participants completed a familiarization session and trial measurements to reduce learning-related variability during the actual assessments. Baseline measurements were then performed, and participants were allocated into four study groups according to their pretest results: respiratory muscle training, respiratory muscle training plus walking exercise, walking exercise, and control.

The respiratory muscle training intervention was performed for 8 weeks using a pressure-threshold respiratory muscle training device. The training load was set at 50% of each participant's maximal inspiratory pressure. Participants in the respiratory muscle training group performed the intervention 5 days per week, twice daily, with 30 breaths in each session. Respiratory muscle strength was reassessed weekly, and the training load was updated according to changes in maximal inspiratory pressure.

The combined intervention group completed the same respiratory muscle training protocol in addition to a structured walking exercise program. The walking exercise consisted of 40 minutes of walking, 3 days per week, either outdoors or on a treadmill, at a pace of approximately 4 to 6 km/hour. Exercise intensity was prescribed using a target heart rate approach corresponding to 40% intensity and was monitored during the sessions with an optical heart rate sensor. Before walking exercise, participants completed a 10-minute warm-up and stretching routine for the upper and lower extremities.

The walking exercise group completed only the structured walking program using the same frequency, duration, intensity, and monitoring procedures as the walking component of the combined intervention group. The control group did not receive a structured exercise intervention and continued their usual daily routine during the study period.

Study data were collected using individual participant forms. These forms included health history, medication use, smoking status, previous physical activity status, basic physical characteristics, and all pre- and post-intervention measurement values. The intervention process and exercise sessions were monitored throughout the study period. Measurements were repeated after the 8-week intervention period to evaluate changes within and between the study groups.