Effects of breathing exercises on breathing patterns in obese and non-obese subjects

Chest physiotherapy in connection with abdominal surgery includes different deep-breathing exercises to prevent post-operative pulmonary complications. The therapy is effective in preventing pulmonary complications, especially in high-risk patients such as obese persons. The mechanisms behind the effect is unclear, but part of the effect may be explained by the changes in breathing patterns. The aim of this study was therefore to describe and to analyse the breathing patterns in obese and non-obese subjects during three different breathing techniques frequently used in the treatment of post-operative patients. Twenty-one severely obese [body mass index (BMI) > 40] and 21 non-obese (BMI 19–25) subjects were studied. All persons denied having any lung disease and were non-smokers. The breathing techniques investigated were: deep breaths without any resistance (DB), positive expiratory pressure (PEP) with an airway resistance of approximately +15 cmH₂O (1·5 kPa) during expiration, inspiratory resistance positive expiratory pressure (IR-PEP) with a pressure of approximately –10 cmH₂O (–1·0 kPa) during inspiration. Expiratory resistance as for PEP. Volume against time was monitored while the subjects were sitting in a body plethysmograph. Variables for volume and flow during the breathing cycle were determined. Tidal volume and alveolar ventilation were highest during DB, and peak inspiratory volume was significantly higher than during PEP and IR-PEP in the group of obese subjects. The breathing cycles were prolonged in all techniques but were most prolonged in PEP and IR-PEP. The functional residual capacity (FRC) was significantly lower during DB than during PEP and IR-PEP in the group of obese subjects. FRC as determined within 2 min of finishing each breathing technique was identical to before the breathing manoeuvres.     

New scale to assess breathing movements of the chest and abdominal wall: preliminary reliability testing

[Purpose] Physical examinations for chest movements by inspection and palpation are poorly reproducible. This study aimed to investigate the inter-rater reliability of a new breathing movement scale for patients with respiratory diseases, in clinical practice. [Subjects and Methods] Twenty-six patients with respiratory diseases were enrolled. BMS measurements were obtained during quiet breathing for 13 patients and during deep breathing for the other 13 patients. The BMS used to assess QB and DB movements of the upper chest, lower chest, and abdomen was based on a scale of −1 to 8. Scale values were measured while in the supine position using a pen-sized breathing movement-measuring device used by two raters during the same session. Scale values at five observation points and total values were recorded. A weighted Kappa coefficient and percentage agreement were used to assess inter-rater reliability with this BMS. [Results] The weighted Kappa coefficients during quiet and deep breathing had substantial to excellent strength of agreement (0.63–1.00) with percentage agreements of 31–100%. [Conclusion] Our results provide preliminary evidence to support the reliability of breathing movement scale measurements to assess breathing movements and chest and abdominal mobility for patients with respiratory diseases.Key words: Reliability, Breathing, Thoracic wall     

Breathing efficiency during inspiratory threshold loading in patients with chronic obstructive pulmonary disease

Patients with chronic obstructive pulmonary disease (COPD) demonstrate an increased oxygen cost of breathing. It is as yet unclear whether this is related to a decreased breathing efficiency. The aim of the present study was to compare breathing efficiency in 16 patients with COPD (11 men, five women) and 16 healthy elderly subjects (seven men, nine women), and to investigate a possible relationship between breathing efficiency and resting energy expenditure (REE). REE was measured using a ventilated hood system. Breathing efficiency was assessed by measuring oxygen consumption (V ^′O ₂), mean inspiratory mouth pressure (MIP) and flow during breathing at rest and subsequently during breathing against an inspiratory threshold (40% of maximal inspiratory pressure). During loaded breathing there was a significant increase in V ^′O ₂, MIP, and external work of breathing compared with unloaded breathing in both groups. As intended, ventilation did not increase significantly during the breathing efficiency test in the patients with COPD. The breathing efficiency (median, range) of the patients with COPD was similar (3·7%, 1·4–8·7%) to that of the healthy elderly subjects (3·2%, 1·7–8·3%). Breathing efficiency was not correlated with REE in either group. In the present study, in which dynamic hyperinflation was probably prevented, no difference in breathing efficiency was found between healthy elderly subjects and COPD patients when breathing against an external inspiratory threshold. Furthermore, breathing efficiency was not related to REE in both groups.     

Effects of diaphragm respiration exercise on pulmonary function of male smokers in their twenties

[Purpose] We investigated how diaphragm respiration exercises can affect pulmonary function in long-term male smokers in their twenties. [Subjects and Methods] Twenty-eight healthy males between 20 and 29 years of age were randomly divided into an experimental and a control group (14 members each). The experiment was conducted during 30 min sessions, 3 times a week for 4 weeks. The experimental group performed diaphragm respiration exercises and the control group performed exercises using MOTOmed. Pulmonary function (tidal volume, breathing capacity, inspiratory reserve volume, inspiratory capacity, and expiratory reserve volume) was evaluated and analyzed before and after the experiment. [Results] Our results revealed significant increases in tidal volume, inspiratory reserve volume, inspiratory capacity, and breathing capacity in the experimental group. These increases were greater in the experimental group than in the control group. [Conclusion] In our study, the experimental group which performed diaphragm respiration exercises showed a greater improvement in pulmonary function compared with the control group. It is hypothesized that greater improvement in pulmonary function is expected if diaphragm respiration exercises are implemented taking into account the age of the smokers.Key words: Pulmonary function, Diaphragm respiration exercise, Smoking     

Respiratory pattern of diaphragmatic breathing and pilates breathing in COPD subjects

BACKGROUND:

Diaphragmatic breathing (DB) is widely used in pulmonary rehabilitation (PR) of patients with chronic obstructive pulmonary disease (COPD), however it has been little studied in the scientific literature. The Pilates breathing (PB) method has also been used in the rehabilitation area and has been little studied in the scientific literature and in COPD.

OBJECTIVES:

To compare ventilatory parameters during DB and PB in COPD patients and healthy adults.

METHOD:

Fifteen COPD patients (COPD group) and fifteen healthy patients (healthy group) performed three types of respiration: natural breathing (NB), DB, and PB, with the respiratory pattern being analyzed by respiratory inductive plethysmography. The parameters of time, volume, and thoracoabdominal coordination were evaluated. After the Shapiro-Wilk normality test, ANOVA was applied followed by Tukey''s test (intragroup analysis) and Student''s t-test (intergroup analysis; p<0.05).

RESULTS:

DB promoted increase in respiratory volumes, times, and SpO₂ as well as decrease in respiratory rate in both groups. PB increased respiratory volumes in healthy group, with no additional benefits of respiratory pattern in the COPD group. With respect to thoracoabdominal coordination, both groups presented higher asynchrony during DB, with a greater increase in the healthy group.

CONCLUSIONS:

DB showed positive effects such as increase in lung volumes, respiratory motion, and SpO₂ and reduction in respiratory rate. Although there were no changes in volume and time measurements during PB in COPD, this breathing pattern increased volumes in the healthy subjects and increased oxygenation in both groups. In this context, the acute benefits of DB are emphasized as a supporting treatment in respiratory rehabilitation programs.     

The effect of continuous positive airway pressure versus positive end-expiratory pressure on the diaphragm

Continuous positive airway pressure (CPAP) and positive end-expiratory pressure (PEEP) both increase lung volume and hence may compromise diaphragm function. However, the effects of these two positive airway pressure modalities on inspiratory work of breathing are conflicting. In this study, we compared the effect of CPAP versus PEEP on diaphragm function in spontaneously breathing anesthetized dogs. Eight sodium pentobarbital-anesthetized dogs were randomly exposed to various levels of CPAP and PEEP. Measurements of diaphragmatic shortening, transdiaphragmatic pressure swings, and diaphragmatic electromyogram (EMG) were made. The change in lung volume and diaphragm length was similar at equivalent airway pressures during PEEP or CPAP. Therefore, expiratory muscle recruitment in the two conditions was equivalent. However, tidal diaphragmatic EMG and transdiaphragmatic pressure swings increased markedly during PEEP compared with CPAP. At a PEEP of 18 cm H₂O, crural and costal EMG activities were 185% ± 16% and 163% ± 8% of control, respectively, whereas during CPAP the EMG activity was 66% ± 11 % of control for both the costal and the crural diaphragms (±SE). During PEEP, the duration of neural inspiration (T_IEMG) was greater than the duration of inspiration as measured by airflow (T_IV). On the other hand, during CPAP, T_IEMG was less than T_IV. We conclude that although expiratory muscle recruitment is comparable and tidal volume greater during CPAP, the inspiratory activation of the diaphragm decreases with CPAP but increases markedly with PEEP.     

Implementation of a respiratory drive monitor on a Servo Ventilator

Objective. To design and evaluate a clinical monitor of respiratory drive (P_0.1) and other respiratory variables in a simple way, using a commercial ventilator. Methods. Nine healthy males were studied as they were breathing spontaneously in a Servo 900C Ventilator, at rest and during light exercise (50 W). The ventilator was slightly modified to improve its mechanical performance during spontaneous breathing, and was used as a measuring instrument. All the relevant information was retrieved, calculated and monitored by a PC. Respiratory drive was assessed as occlusion pressures from the inspiratory airway pressure signal. The equipment was compared with a two-way non-rebreathing laboratory system. Furthermore, negative and positive inspiratory pressures were applied from the ventilator, to study respiratory responses to mechanical loads. Results. At rest, the ventilator introduced a minor influence on inspiratory time and P_0.1, but not in ventilatio n, tidal volume, expiratory duration and respiratory frequency. During exercise, the influence was more evident. This effect could also be noticed in the coefficients of variation. The responses to mechanical loads were easily recorded and can be used as a simple test of central load-compensating mechanisms. Conclusions. The ventilator, with limitations, may be an alternative to conventional techniques, especially in clinical studies of the central inspiratory activity with and without respiratory loading.     

Breath-by-breath determination of inspiratory occlusion pressure

Summary. In order to determine the influence of breath-by-breath measurement of inspiratory occlusion pressure (P_0.1) on the pulmonary ventilation, the respiratory timing and the central inspiratory activity as reflected by P_0.1per se, nine healthy males were studied as they breathed in a valve assembly including an externally controlled occlusion valve. A new technique was used, terminating occlusions at a preset inspiratory threshold pressure and determining P_0.1 from linear regression of the mouth pressure curve. Subjects were studied at rest and during light exercise, with the occluding function (threshold pressure) on or off during alternating periods. Breath-by-breath variability of P_0.1 was of the order of 30%. We found no detectable influence of breath-by-breath short-lasting inspiratory occlusions on tidal volume and ventilation. However, mean inspiratory flow was slightly increased due to a shortened inspiratory duration at rest and during light exercise. Also, raising the threshold pressure for occlusions from 69 to 147 Pa (0.7 to 1.5 cm H₂O) resulted in a 20% increase of P_0.1. We conclude that breath-by-breath measurement of P_0.1 is a feasible technique, and that the slightly shortened inspiratory duration and the increased P_0.1 with increased threshold pressure may not necessarily be expressions of a true stimulation of the central inspiratory activity.     

The effect of opioids on inspiratory muscle fatigue during inspiratory resistive loading

Summary. The effect of opioids on inspiratory muscle function under high mechanical load is still unknown. Even less clear is the extent to which opioids influence the shift of the electromyographic power spectrum of the inspiratory muscles to lower frequencies during ventilatory stress. We studied seven healthy subjects breathing against high inspiratory threshold loads until exhaustion while keeping the minute ventilation constantly high. We compared runs with and without administration of 0.2 mg kg^-1 of morphine sulphate intramuscularly; two subjects were given 30 mg morphine sulphate so that we could study the effect of higher opioid concentration. The endurance time (T_lim), the diagraphragmatic electromyogram (EMG), the transdiaphragmatic pressures (Pdi) and the ventilatory effort sensation were analysed. Morphine did not have any effect on T_lim or on the effort sensation elicited by the inspiratory resistance in both concentrations. Analysing the spectral shifts of the diaphragmatic EMG, we did not find any significant difference in the decrease of the centroid frequency between drug and control runs. Furthermore, the activation pattern of the diaphragm and the intercostal muscles, evaluated from the percentage contribution of oesophageal and gastric pressures on the transdiaphragmatic pressure swings, did not change following the administration of morphine. Our study shows that morphine does not change the function of the inspiratory muscles during high-resistive breathing. Morphine does not affect the electromyographic power spectrum of the diaphragm during those resistive breathing runs, either. This points out that during stressful ventilatory situations, the shift of the electromyographic power spectrum is attributed to a peripheral (muscular) event consequent to muscle fatigue and not to the elaboration of endogenous opioids.     

Flow-triggering reduces inspiratory effort during weaning from mechanical ventilation

Objective To investigate whether a new flow-triggered (FT) system can reduce the patient's inspiratory effort compared to a traditional pressure-triggered (PT) system during weaning from mechanical ventilation.Design Prospective study.Setting Intensive care unit of a General Hospital.Patients and participants 10 mechanically ventilated patients, without chronic airway disease, ready to wean.Measurements Minute ventilation, breathing pattern, lung mechanics, inspiratory work of breathing (WI) and pressure time product (PTP) of Ppl were obtained in two conditions: 1) unsupported spontaneous breathing through the ventilator circuit (SB); 2) spontaneous breathing with continuous positive airway pressure set at 5 cmH₂O (CPAP). Two triggering systems, namely PT and FT, were used in each condition.Results Though there was no change in breathing pattern, minute ventilation, and lung mechanics, the magnitude of the inspiratory effort decreased significantly with FT compared to PT in both instances. The added resistance (total flow resistance minus pulmonary resistance) decreased by 37% on average when FT replaced PT. PTP decreased, on average, 27% and 15% during SB and CPAP, respectively, with FT compared to PT (p<0.05). A similar significant decrease was observed in WI.Conclusion The new FT system, i.e. flow-by system, reduces the unintentional ventilatory workload upon the patients' inspiratory muscles compared to traditional PT system during weaning from mechanical ventilation.     

Glottic-modulated lung ventilation during continuous transtracheal gas insufflation: an experimental study

We investigated a new method of pulmonary ventilation that included a minitracheostomy, a reverse thrust catheter to deliver continuous flow of gas to the carina, and a threshold valve to avoid lung overinflation. In six lightly sedated healthy sheep, at a continuous flow of 5, 10, or 15 L/min and a threshold valve of 5, 10, 15, or 20 cm H(2)O, we observed a novel respiratory pattern that was characterized either by active lung inflation followed by passive and prolonged inspiratory hold (mixed pattern) or by an absence of all active inspiratory effort and only passive inflation of the lungs (passive pattern). We correlated airway pressure changes with direct visualization of the glottic opening through a fiberoptic bronchoscope. We measured airway pressures at the level of the carina, the subglottic level, and in the pleural space, and respiratory events were monitored through inductive plethysmography. An increase in continuous flow, threshold valve, or both resulted in 1) an increase in glottic breathing; 2) a decrease in respiratory rate, with a decrease in inspiratory pleural pressure excursion; or 3) an increased inspiratory/expiratory ratio and mean airway pressure. During transtracheal gas insufflation, as in this study, a novel respiratory pattern evolved that was modulated by the glottis, accompanied by a decreased effort of breathing; coughing and swallowing remained, and vocalization remained unimpaired.     

Respiratory characteristics of individuals with non‐specific low back pain: A cross‐sectional study

Non‐specific low back pain (NS‐LBP) is known to cause respiratory dysfunction. In this study, we investigated alterations in breathing, respiratory strength and endurance, core stability, diaphragm mobility, and chest expansion among patients with NS‐LBP and healthy individuals. The specific aim of the study was to correlate between respiratory function and other variables among NS‐LBP patients. Thirty four patients with NS‐LBP were matched with 34 healthy participants before undergoing total faulty breathing scale, spirometer, respiratory pressure meter, chest expansion, ultrasound, and pressure biofeedback measurements. There were signs of faulty breathing in the NS‐LBP patients when compared to the healthy participants. Diaphragmatic mobility and respiratory muscle endurance were lower in the NS‐LBP group. Chest expansion exhibited a significant decrease at the level of the fourth intercostal space in the NS‐LBP group, but respiratory muscle strength and core stability were not significant between the two groups. Positive correlations were found to be fairly significant regarding respiratory muscle strength. The findings of this study indicated altered respiratory characteristics in the NS‐LBP patients, and suggested that they would improve through respiratory exercises.     

The changes of pulmonary function and pulmonary strength according to time of day: a preliminary study

[Purpose] The purpose of this study was to identify changes in pulmonary function and pulmonary strength according to time of day. [Subjects and Methods] The subjects were 20 healthy adults who had no cardiopulmonary-related diseases. Pulmonary function and pulmonary strength tests were performed on the same subjects at 9:00 am, 1:00 pm, and 5:00 pm. The pulmonary function tests included forced vital capacity (FVC), forced expiratory volume in 1 second (FEV₁), and forced expiratory flow between 25 and 75% of vital capacity (FEF_25–75%). Pulmonary strength tests assessed maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP). [Results] FEV1 showed statistically significant differences according to time of day. Other pulmonary function and pulmonary strength tests revealed no statistical differences in diurnal variations. [Conclusion] Our findings indicate that pulmonary function and pulmonary strength tests should be assessed considering the time of day and the morning dip phenomenon.Key words: Breathing, Time of day, Diurnal variations     

Respiratory Dysfunction in Individuals With Thoracic Outlet Syndrome

ObjectiveThe purpose of this study was to compare pulmonary function and respiratory muscle strength and endurance in individuals with thoracic outlet syndrome (TOS) and healthy participants.MethodsSixty-two individuals with TOS (mean age 30.81 ± 10.69 years; 10 male, 52 female) and 47 healthy individuals (mean age 30.64 ± 9.16 years; 14 male, 33 female) participated in this study. Pulmonary function testing was performed using a spirometer. Respiratory muscle strength (maximal inspiratory pressure [MIP] and maximal expiratory pressure [MEP]) were measured using a mouth pressure device. Respiratory muscle endurance was tested at 35% MIP and measured as the time in seconds from the start of the test to voluntary exhaustion.ResultsAge distribution and physical characteristics were similar between the groups (P > .05). All pulmonary function parameters except for peak expiratory flow rate were similar in patients with TOS and healthy controls (P > .05). Patients with TOS had significantly lower peak expiratory flow rate, MIP, MIP%, MEP, MEP%, and respiratory muscle endurance compared with controls (P < .05). Forty-six patients with TOS (74.2%) had MIP values below the lower limit of the 95% CI of the control group (97.05-113.88 cmH₂O), and 53 patients with TOS (85.2%) had MEP values below the lower limit of the 95% CI of the control group (124.74-146.49 cmH₂O).ConclusionExpiratory flow rate and respiratory muscle strength and endurance may be adversely affected in TOS. Trunk muscles perform both postural and breathing functions. Therefore, disruption in one function may negatively affect the other.     

Comparison of pressure support ventilation and assist control ventilation in patients with acute respiratory failure

We compared the effects of pressure support ventilation (PSV) with those of assist control ventilation (ACV) on the breathing pattern, work of breathing and blood gas exchange in 8 patients with acute respiratory failure. During ACV, the tidal volume was set at 10 ml/kg, and the inspiratory flow was set at 50 to 70l/min. During PSV, the pressure support level selected was 27±5 cm H₂O to make the breathing pattern regular. Tidal volume was significantly higher (908±179 ml vs. 633±96 ml) during PSV than during ACV at a lower peak airway pressure. Respiratory frequency was lower (15±4 breaths/min vs. 24±5 breaths/min) during PSV than during ACV, associated with a lower duty cycle, which improved synchrony between the patient and the ventilator. The oxygen cost of breathing, and estimate based on the inspiratory work added by a ventilator and the oxygen consumption, did not change significantly. PaO₂ was significantly higher during PSV than during ACV. We conclude that PSV using high levels of pressure support can improve the breathing pattern and oxygenation and fully sustain the patient's ventilation while matching his inspiratory efforts.     

The influences of position and forced respiratory maneuvers on spinal stability muscles

[Purpose] The purposes of this study were to investigate the influences of position on %MVIC of spinal stability muscles to establish for the most effective breathing pattern for activation of spinal stability muscles in order to provide an additional treatment method for use in spinal stability exercise programs. [Subjects and Methods] Thirty-three healthy subjects performed quiet breathing and four different forced respiratory maneuvers (FRM); [pursed lip breathing (PLB), diaphragmatic breathing (DB), combination breathing (CB) and respiration muscle endurance training (RMET)] in both standing and sitting positions. %MVIC of them (the multifidus (MF), erector spinae (ES), internal oblique/transversus abdominis (IO/TrA), external oblique (EO), rectus abdominis (RA) measured. [Results] IO/TrA, MF and EO showed greater activation in standing than in sitting, while RA and ES showed greater activation in sitting than in standing. RMET induced significantly greater activation of spinal stability muscles then other breathing patterns. %MVIC changes of muscle activities induced by FRM were independent of position with a few exceptions. [Conclusion] The increased respiratory demands of FRM induced greater activation of spinal stability muscles than QB. RMET was found to be the most effective breathing pattern for increasing the activation of the spinal stability muscles.Key words: Spinal stability muscles, Position, Forced respiratory maneuvers     

Imposed power of breathing associated with use of an impedance threshold device

OBJECTIVE: To measure the imposed power of breathing (imposed work of breathing per minute) associated with spontaneous breathing through an active impedance threshold device and a sham impedance threshold device. DESIGN: Prospective randomized blinded protocol. SETTING: University medical center. PATIENTS: Nineteen healthy, normotensive volunteers (10 males, 9 females, age range 20-56 y, mean +/- SD weight 54.8 +/- 7.7 kg for females, 84 +/- 8 kg for males). METHODS: The volunteers completed 2 trials of breathing through a face mask fitted with an active impedance threshold device set to open at -7 cm H(2)O pressure, or with a sham impedance threshold device, which was identical to the active device except that it did not contain an inspiratory threshold pressure valve diaphragm. Spontaneous breathing frequency (f), tidal volume (V(T)), exhaled minute ventilation, inspiratory pressure, and inspiratory time were measured with a respiratory monitor, and the data were directed to a laptop computer for real-time calculation of the imposed power of breathing. RESULTS: There were no significant differences in heart rate, respiratory rate, tidal volume, and minute ventilation, with and without inspiratory impedance. For the sham and active impedance threshold device groups, respectively, the mean +/- SD imposed power of breathing values were 0.92 +/- 0.63 J/min and 8.18 +/- 4.52 J/min (p < 0.001), the mean +/- SD inspiratory times were 1.98 +/- 0.86 s and 2.97 +/- 1.1 s (p = 0.001), and the mean +/- SD inspiratory airway/mouth pressures were -1.1 +/- 0.6 cm H(2)O and -11.7 +/- 2.4 cm H(2)O (p < 0.001). CONCLUSIONS: Breathing through an active impedance threshold device requires significantly more power than breathing through a sham device. All subjects tolerated the respiratory work load and were able to complete the study protocol.     

Cardiovascular autonomic nervous system tests: reference values in young people (15-19 years) and influence of age and gender

Objective: The aim of this study was to determine values of the deep breathing test (DB), orthostatic test (OT) and Valsalva manoeuvre (VM) parameters in young people and influence of age and gender. Methods: A total of 206 healthy subjects (100 girls, 106 boys) at the age of 15–19 years, BMI 21·3±2·3 (mean ± SD) were examined by system Varia Pulse TF3. Results: Reference values of DB, OT, VM parameters are presented as arithmetic mean ± SD and percentiles (P₉₀, P₇₅, P₅₀, P₂₅, P₁₀). In the whole group HRrest was lower in 19‐year‐old group, in OT this difference was significant already in 18‐year‐old group compared with 15‐year‐old group. DB: I/E was significantly increased in 19‐year‐old group compared with 15‐year‐old group. HRrest was higher in girls compared with boys in the whole group. DB: I/E was significantly lower in girls compared with boys. OT: 30:15 and HRmax/HRrest were significantly decreased in girls compared with boys. Conclusion: Reference values of DB, OT, VM parameters were determined in young people at the age of 15–19 years. The most sensitive test for ascertainment of developmental changes was test of deep breathing. I/E was increased in the 19‐year‐old group compared with 15‐year‐old group indicating an increase of vagal activity. Girls had decreased some parameters of deep breathing and orthostatic test compared with boys in the same group (15–19 years).     

Home-based respiratory muscle training on quality of life and exercise tolerance in long-term post-COVID-19: Randomized controlled trial

ObjectiveTo evaluate the effects of a home-based respiratory muscle training programme (inspiratory [IMT] or inspiratory/expiratory muscles [RMT]) supervised by telerehabilitation on quality of life and exercise tolerance in individuals with long-term post-COVID-19 symptoms. The secondary objective was to evaluate the effects of these programmes on respiratory muscle function, physical and lung function, and psychological state.Methods88 individuals with long-term symptoms of fatigue and dyspnoea after COVID-19 diagnosis were randomly (1:1 ratio) assigned to IMT, IMT_sham, RMT or RMT_sham groups for an 8-week intervention (40min/day, 6 times/week). Primary outcomes were quality of life (EuroQol-5D questionnaire) and exercise tolerance (Ruffier test). Secondary outcomes were respiratory muscle function (inspiratory/expiratory muscle strength; inspiratory muscle endurance), physical function (lower and upper limb strength [1-min Sit-to-Stand and handgrip force]), lung function (forced spirometry), and psychological status (anxiety/depression levels and post-traumatic stress disorder). All outcomes were measured pre-, intermediate- (4^th week), and post-intervention.ResultsAt post-intervention, there was a statistically significant and large (d>0.90) improvement in quality of life, but not in exercise tolerance, in the RMT group compared with the RMT_sham group. Both of the real training groups produced a statistically significant and large increase in inspiratory muscle strength and endurance (d≥0.80) and in lower limb muscle strength (d≥0.77) compared with the 2 sham groups. Expiratory muscle strength and peak expiratory flow showed a statistically significant and large (d≥0.87) increase in the RMT group compared with the other 3 groups.ConclusionOnly an 8-week supervised home-based RMT programme was effective in improving quality of life, but not exercise tolerance, in individuals with long-term post-COVID-19 symptoms. In addition, IMT and RMT programmes were effective in improving respiratory muscle function and lower limb muscle strength, but had no impact on lung function and psychological status.