Cardiorespiratory Response to Different Exercise Tests in Interstitial Lung Disease

Assessing Functional Capacity in Directly and Remotely Monitored Home-Based Settings in Individuals With Chronic Respiratory Diseases: Protocol for a Multinational Validation Study

BACKGROUND

Pulmonary rehabilitation is widely recommended to improve functional status and as secondary and tertiary prevention in individuals with chronic pulmonary diseases. Unfortunately, access to timely and appropriate rehabilitation remains limited. To help close this inaccessibility gap, telerehabilitation has been proposed. However, exercise testing is necessary for effective and safe exercise prescription. Current gold-standard tests, such as maximal cardiopulmonary exercise testing (CPET) and the 6-minute walk test (6MWT), are poorly adapted to home-based or telerehabilitation settings. This was an obstacle to the continuity of services during the COVID-19 pandemic. It is essential to validate tests adapted to these new realities, such as the 6-minute stepper test (6MST). This test, strongly inspired by 6MWT, consists of taking as many steps as possible on a "stepper" for 6 minutes.

OBJECTIVE

This study aims to evaluate the metrological qualities of 6MST by (1) establishing concurrent validity and agreement between the 6MST and CPET, as well as with the 6MWT; (2) determining test-retest reliability in a home-based setting with direct and remote (videoconferencing) monitoring; and (3) documenting adverse events and participant perspectives when performing the 6MST in home-based settings.

METHODS

Three centers (Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec in Québec, Groupement des Hôpitaux de l'Institut Catholique de Lille in France, and FormAction Santé in France) will be involved in this multinational project, which is divided into 2 studies. For study 1 (objective 1), 30 participants (Québec, n=15; France, n=15) will be recruited. Two laboratory visits will be performed to assess anthropometric data, pulmonary function, and the 3 exercise tolerance tests (CPET, 6MWT, and 6MST). Concurrent validity (paired sample t tests and Pearson correlations) and agreement (Bland-Altman plots with 95% agreement limits) will be evaluated. For study 2 (objectives 2 and 3), 52 participants (Québec, n=26; France, n=26) will be recruited. Following a familiarization trial (trial 1), the 6MST will be conducted on 2 separate occasions (trials 2 and 3), once under direct supervision and once under remote supervision, in a randomized order. Paired sample t test, Bland-Altman plots, and intraclass correlations will be used to compare trials 2 and 3. A semistructured interview will be conducted after the third trial to collect participants' perspectives.

RESULTS

Ethical approval was received for this project (October 12, 2023, in Québec and September 25, 2023, in France) and the first participant was recruited in February 2024.

CONCLUSIONS

This study innovates by validating a new clinical test necessary for the development and implementation of new models of rehabilitation adapted to home and telerehabilitation contexts. This study also aligns with the United Nations Sustainable Development Goals by contributing to augmenting health care service delivery (goal 3) and reducing health care access inequalities (goal 11).

TRIAL REGISTRATION

ClinicalTrials.gov NCT06447831; https://clinicaltrials.gov/study/NCT06447831.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/57404.

Which field test should be used to compare the functional exercise capacities of patients with type 2 diabetes mellitus with and without diabetic peripheral neuropathy? Cross-sectional study

BACKGROUND

The 6-minute step test (6MST) has begun to be used as a simple and effective alternative for assessing functional exercise capacity. There is no study using 6MSTs to evaluate the exercise capacities of patients with type 2 diabetes mellitus (DM) with and without diabetic peripheral neuropathy (DPN).

OBJECTIVE

To compare the cardiorespiratory responses of the 6-minute walk test (MWT) and the 6MST exercise tests and to analyze the usability of the 6MST in Type 2 DM patients with and without neuropathy.

METHODS

32 non-neuropathic Type 2 DM, 32 neuropathic Type 2 DM patients, and 30 healthy volunteers were included in this cross-sectional study. Functional exercise capacity was evaluated with the 6MWT and the 6MST. The 30-second sit-stand test (30s STS) was used to evaluate general lower extremity muscle strength and function.

RESULTS

There was a significant difference in the results of 6MWT (m), 6MST (number of steps), and 30s STS of the three groups (p<0.05). The 6MST results of patients with neuropathic Type 2 DM were significantly lower than those of non-neuropathic diabetics and those who were healthy (number of steps; 114.07±25.57 vs. 133.48±33.57 vs. 160.35±28.52, respectively) (p=0.001). The change in cardiorespiratory response in systolic blood pressure, heart rate, perceived dyspnea, and leg fatigue severity was significantly higher at 6MST than 6MWT in the three groups (p<0.05). 6MST was correlated with 6MWT (r=0.679, p=0.001), and 30s STS (r=0.589, p=0.001) in patients with Type 2 DM.

CONCLUSIONS

Cardiorespiratory responses increased more in 6MST compared to 6MWT. In patients with Type 2DM, 6MWT and 6MST were moderately correlated with each other. 6MST is an effective and safe assessment method that may better reveal the differences in functional exercise capacity between neuropathic and non-neuropathic individuals in clinics.

Use of the six-minute walk test in exercise prescription in male patients after coronary artery bypass surgery

INTRODUCTION

It is unclear whether it is possible to determine the training load on the basis of the 6-minute walk test (6-MWT) in patients after cardiac surgery with low tolerance of physical exercise.

AIM

Use of the 6-MWT to determine an individual initial training load in walking training on a treadmill in the early phase of cardiac rehabilitation in men after coronary artery bypass graft (CABG) surgery.

MATERIAL AND METHODS

Twenty-two men aged 54 to 74 years, up to 3 months after CABG surgery participated in walking training on a treadmill (12-15 sessions). Patients underwent the initial and final treadmill exercise stress test (TEST) and the 6-MWT. Based on 6-MWT results, the initial training load was prescribed. Before the 6-MWT and 3 minutes after its completion, lactate concentration was determined.

RESULTS

The 6-MWT distance increased from 420 ±80 m to 519 ±61 m (p < 0.001), and the energy expenditure from 4.4 ±1.4 MET to 6.3 ±1.3 MET (p < 0.001). There was a positive correlation between 6-MWT distance and energy expenditure in the TEST before rehabilitation (r = 0.60, p = 0.005), and after rehabilitation (r = 0.75, p < 0.001). A negative correlation was found between the baseline 6-MWT distance and distance increment in the final 6-MWT (r = -0.66, p = 0.002). The 6-MWT did not induce hyperlactatemia.

CONCLUSIONS

The 6-MWT can be used in exercise intensity prescription, especially for determining the individual initial training load, load progression, as well as its correction during follow-up tests.

Home-based or remote exercise testing in chronic respiratory disease, during the COVID-19 pandemic and beyond: A rapid review

Objectives:

To identify exercise tests that are suitable for home-based or remote administration in people with chronic lung disease.

Methods:

Rapid review of studies that reported home-based or remote administration of an exercise test in people with chronic lung disease, and studies reporting their clinimetric (measurement) properties.

Results:

84 studies were included. Tests used at home were the 6-minute walk test (6MWT, two studies), sit-to-stand tests (STS, five studies), Timed Up and Go (TUG, 4 studies) and step tests (two studies). Exercise tests administered remotely were the 6MWT (two studies) and step test (one study). Compared to centre-based testing the 6MWT distance was similar when performed outdoors but shorter when performed at home (two studies). The STS, TUG and step tests were feasible, reliable (intra-class correlation coefficients >0.80), valid (concurrent and known groups validity) and moderately responsive to pulmonary rehabilitation (medium effect sizes). These tests elicited less desaturation than the 6MWT, and validated methods to prescribe exercise were not reported.

Discussion:

The STS, step and TUG tests can be performed at home, but do not accurately document desaturation with walking or allow exercise prescription. Patients at risk of desaturation should be prioritised for centre-based exercise testing when this is available.

The 1-minute sit-to-stand test to detect exercise-induced oxygen desaturation in patients with interstitial lung disease

BACKGROUND

Although the 6-min walk test (6MWT) is the gold standard for assessing exercise-induced impairment of gas exchange, it cannot easily be performed in a clinical office environment. The aim of this study was to compare the 1-min sit-to-stand test (1STST) with the 6MWT for the ability to assess exercise-induced oxygen desaturation in patients with interstitial lung diseases (ILDs).

METHODS

A total of 107 patients were enrolled and classified into three groups: sarcoidosis, fibrotic idiopathic interstitial pneumonia (f-IIP), and other forms of ILD. The 6MWT and 1STST were performed on the same day, and pulmonary function tests, pulse oxygen saturation (SpO2), and dyspnea and fatigue (modified Borg scale) were assessed. SpO2 desaturation was evaluated by intraclass correlation coefficient (ICC), Bland-Altman analysis, and kappa (κ) coefficient in the whole population and the patient subgroups.

RESULTS

The SpO2 nadir during the 1STST and 6MWT showed good consistency [mean ± standard deviation: 92.5% ± 5% and 90% ± 7%, respectively; ICC 0.77, 95% confidence interval (CI) 0.71-0.83] and correlated strongly ( r = 0.9, p < 0.0001). The frequency of patients with oxygen desaturation ⩾4% was also consistent for the two exercise tests ( κ = 0.68, 95% CI 0.54-0.82). The number of repetitions in the 1STST correlated with the 6MWT distance ( r = 0.5, p < 0.0001), but the dyspnea scores were higher during the 1STST than the 6MWT ( p < 0.0001). These findings did not differ for the three patient subgroups.

CONCLUSION

The 1STST can measure exercise-induced desaturation in ILD patients and could be used as an alternative test to the 6MWT in office practice.

Relationships between heart rate target determined in different exercise testing in COPD patients to prescribed with individualized exercise training

Background

It has been scientifically proven that pulmonary rehabilitation improves exercise tolerance and facilitates the carrying out of daily physical activities. To optimize the physical and physiological benefits, it is necessary to individualize the training intensity for each patient. The aim of this study is to compare the heart rate (HR) responses to three exercise modalities measuring aerobic fitness in chronic obstructive pulmonary disease patients, in order to easily prescribe individual target HRs for endurance training.

Patients and method

Fifty COPD patients (mean age: 60.1±8.5 years) were included in the study. Each patient carried out a cardiopulmonary exercise test, a 6-minute walk test (6MWT) and a 6-minute stepper test (6MST). During these tests, HR was recorded continuously. After the cardiopulmonary exercise test, the HR was noted at the ventilatory threshold (VT) and at the end of the two exercise field tests (6MWT_peak and 6MST_peak). The values of the HR during the last 3 minutes of both field tests were averaged (6MWT₄₅₆ and 6MST₄₅₆). Finally, the HR at 60% of the HR reserve was calculated with the values of the HR measured during 6MWT and 6MST (HRr_60%walk, HRr_60%step).

Results

The HRs measured during the 6MST were significantly higher than those measured during the 6MWT. The HRr_60%step was not significantly different from 6MWT₄₅₆ and 6MWT_peak HR (P=0.51; P=0.48). A significant correlation was observed between 6MWT₄₅₆ and 6MWT_peak (r=0.58). The 6MWT₄₅₆ and 6MWT_peak HR were correlated with HRr_60%step (r=0.68 and r=0.62). The VT could be determined in 28 patients. The HR_VT was not different from 6MWT₄₅₆, 6MWT_peak, and HRr_60%step (P=0.57, P=0.41 and P=0.88) and was correlated to 6MWT₄₅₆, 6MWT_peak, and HRr_60%step (r=0.45, r=0.40, r=0.48).

Conclusion

An individualized target HR for endurance training can be prescribed from the HR measured during routine tests, such as 6MWT or 6MST.