Respiratory Muscle Training and Walking Exercise in Women Recovering From COVID-19 Pneumonia

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.

Inclusion criteria

• Female participants aged 20 to 45 years
• History of COVID-19-related pneumonia
• Presence of dyspnea after COVID-19
• Modified Borg dyspnea score between 1 and 7 after the 6-minute walk test
• Resting oxygen saturation between 90% and 95%
• Incomplete resolution of COVID-19-related lesions on chest radiography
• Voluntary agreement to participate in the study
• Signed written informed consent form

Exclusion criteria

• Modified Borg dyspnea score between 0 and 1
• Modified Borg dyspnea score greater than 7
• History of chronic obstructive pulmonary disease, heart failure, or pulmonary fibrosis causing dyspnea before COVID-19 pneumonia
• Upper abdominal or thoracic surgery within the previous 3 months
• Cancer
• Pregnancy
• Presence of another disease contributing to dyspnea in addition to COVID-19-related dyspnea
• Cardiovascular, musculoskeletal, or nervous system involvement related to COVID-19
• Mental disorder or mental instability
• Language barrier preventing understanding of Turkish
• Refusal to participate or withdrawal from the study at any stage
• History of being a competitive athlete
• Lack of voluntary participation or refusal to sign the written informed consent form