Cardiopulmonary response during incremental shuttle walking test in a hallway versus on treadmill in Phase IV cardiac rehabilitation: a cross-sectional study
Osailan A. Cardiopulmonary response during incremental shuttle walking test in a hallway versus on treadmill in Phase IV cardiac rehabilitation: a cross-sectional study. Scientific Reports. 2023;13(1). doi:10.1038/s41598-023-39999-2Link to Original Article: https://www.nature.com/articles/s41598-023-39999-2
Key Points
1. The incremental shuttle walking test (ISWT) is commonly used to measure functional capacity in cardiac rehabilitation patients.
2. When physical space is limited, an incremental shuttle walking test on a treadmill (ISWT-T) has been suggested as an alternative.
3. This study aimed to compare the cardiopulmonary responses between ISWT and ISWT-T and investigate factors associated with the distance achieved in both tests.
4. Thirteen participants attending phase IV cardiac rehabilitation participated in the study.
5. The study found no significant differences in the cardiopulmonary responses between ISWT and ISWT-T, except for peak oxygen uptake (VO2PEAK).
6. Age and height were significantly correlated with the distance achieved in both tests, while leg length was only correlated with the distance achieved on ISWT-T.
7. The findings suggest that ISWT-T evoked a higher metabolic demand than ISWT, but the difference in cardiopulmonary responses was marginal and not clinically relevant.
8. ISWT-T can be used as an alternative to ISWT in cases of physical space limitation, but exercise training should be based on actual assessment and measurement during the tests.
9. Further research with a larger and more diverse sample is needed to confirm these findings.
Introduction
The incremental shuttle walking test (ISWT) is a widely used field test to measure functional capacity in patients with chronic obstructive pulmonary diseases and cardiovascular diseases. It involves walking on a flat surface marked with cones while following audible bleeps. However, finding an appropriate physical space to conduct the test can be challenging, leading to the suggestion of performing ISWT on a treadmill (ISWT-T). Previous studies have found no differences in walking distance and physiological responses between ISWT and ISWT-T. However, it has also been argued that there may be a reduction in walking distances achieved on a treadmill compared to a hallway. Gait mechanics and energy demands may differ between walking on a treadmill and in a hallway, which could impact physiological responses. ISWT and ISWT-T are commonly used as field tests in cardiac rehabilitation, with ISWT-T being an alternative when physical space is limited. However, there is limited knowledge about the physiological responses and differences between the two tests, particularly in Phase IV cardiac rehabilitation patients. The current study aims to compare cardiopulmonary responses between ISWT and ISWT-T in Phase IV cardiac rehabilitation attendees and investigate factors associated with the achieved distance of each test. It is hypothesized that both tests will produce similar physiological responses. This information will help determine if ISWT-T can be used as an alternative to ISWT when physical space is limited.
Methods
The study recruited thirteen participants (66.3 ± 7.3 years, 84.6% males) from a cardiac rehabilitation center. Inclusion criteria were cardiac revascularization and confirmed diagnosis of stable cardiovascular disease, while exclusion criteria included musculoskeletal disorders, neurological conditions, unstable hypertension, and uncontrolled diabetes, among others. The study had a power of 0.82 with an effect size of 0.75. The study was conducted following the Declaration of Helsinki and approved by the ethical committee at the university. The study protocol involved two visits, with participants randomized to perform the Incremental Shuttle Walking Test (ISWT) or ISWT on a treadmill first, with a familiarization period before starting the test. Measurements such as height, weight, resting heart rate, and resting blood pressure were taken before the test. Participants wore a heart rate monitor and a face mask connected to a gas analyzer during the test. The ISWT was performed on a non-slippery surface with cones set 9m apart, consisting of 12 levels with increasing speed. The test was terminated if termination criteria were met, including angina symptoms, severe shortness of breath, or failure to meet speed requirements. The ISWT on a treadmill followed a similar protocol, with termination criteria being the inability to maintain speed. The same variables were measured during both tests.
Gas Exchange Analysis
In this study, a portable breath-by-breath gas analyzer was used to analyze the gas exchange during two tests and the recovery period. The variables measured included the volume of oxygen (VO2), carbon dioxide (CO2), minute ventilation (VE), and tidal volume (VT). The highest recorded VO2 during each test was defined as VO2PEAK and expressed as VO2 ml/kg/min.
Anthropemetic Measurements
Additionally, anthropometric measurements such as waist circumference and leg length were taken. Waist circumference was measured using a tape placed in the middle between the bottom of the ribs and the top of the hips, while leg length was measured from the anterior superior iliac spine to the medial distance. During the Incremental Shuttle Walk Test (ISWT), the distance covered was measured by multiplying the number of shuttles performed by the total distance of the course (10 m). After the test was terminated, the distance was measured from the last cone to the participant's sitting spot. During the ISWT-T, the distance was automatically recorded from the treadmill's control display.
Conclusions
Comparison in cardiopulmonary response between ISWT and ISWT-T.
This research paper aimed to compare the cardiopulmonary responses between the Incremental Shuttle Walking Test (ISWT) and the ISWT-T. The study found that there were no significant differences in the cardiopulmonary responses, except for VO2PEAK.
Factors related to the achieved distance in ISWT and ISWT-T
The achieved distance in both tests was also analyzed, and age was strongly and inversely correlated with the distance achieved in both ISWT and ISWT-T. Height was moderately correlated with the distance achieved in both tests as well. Leg length, on the other hand, was only moderately correlated with the distance achieved in the ISWT-T. Overall, this study provides insights into the similarities and factors influencing cardiopulmonary responses and achieved distance in these tests.
Discussions
This study compared the cardiopulmonary responses between the Incremental Shuttle Walk Test (ISWT) and ISWT on a treadmill (ISWT-T) and examined factors associated with the achieved distance in each test. The results showed that both tests produced similar cardiopulmonary responses, except for peak oxygen consumption (VO2PEAK). Age and height were strongly associated with the achieved distance in both tests, while leg length was moderately associated with distance achieved on ISWT-T only. ISWT produced higher cardiorespiratory and metabolic demands than ISWT-T in phase IV cardiac rehabilitation. In clinical practice, ISWT and ISWT-T are reliable and valid assessment tools for cardiac rehabilitation programs. There was no significant difference in cardiovascular response between the two tests, although previous studies have reported conflicting findings. The 6-minute walking test (6MWT) performed on a treadmill resulted in shorter distances achieved compared to field tests. ISWT and ISWT-T showed similar pulmonary responses, except for VO2PEAK, which was higher during ISWT. ISWT-T may be a viable alternative in limited physical space, while ISWT can be used when laboratory access is limited. Age, height, and leg length were associated with achieved distance in both tests, emphasizing the importance of individualized assessments. In conclusion, ISWT and ISWT-T have similar cardiopulmonary responses, and factors such as age, height, and leg length influence the achieved distance. Exercise training should be based on actual measurements and assessments of functional capacity during these tests.
Opportunities for Future Research
1. Further research is needed to investigate the differences in cardiopulmonary response between the incremental shuttle walking test (ISWT) and the incremental shuttle walking test on a treadmill (ISWT-T) in various populations, such as individuals with chronic obstructive pulmonary disease (COPD) or other clinical populations.
2. Future studies should explore the energy cost per meter and metabolic demands of ISWT and ISWT-T in different settings and conditions, such as at different walking speeds or in individuals with different levels of physical fitness.
3. Additional research is warranted to examine the factors associated with the distance achieved during ISWT and ISWT-T in larger and more diverse populations, including individuals with different cardiac conditions and varying levels of functional capacity.
4. Further investigation is needed to determine the impact of familiarity with walking on a treadmill on the cardiopulmonary response during ISWT-T, particularly in older individuals or those who are not accustomed to using a treadmill.
5. Future studies should explore the influence of gait mechanics on the physiological responses during ISWT and ISWT-T, including the energy demands of maintaining balance during treadmill walking.
6. Additional research is needed to determine the clinical significance of the marginal difference in peak oxygen uptake (VO2peak) between ISWT and ISWT-T, particularly in terms of its impact on exercise prescription and functional capacity assessment.
7. Further studies should explore the association between leg length and the distance achieved during ISWT and ISWT-T, including the influence of stride length on walking performance in these tests.
8. Future research could investigate the differences in cardiopulmonary response and factors associated with distance achieved during ISWT and ISWT-T in individuals with different heights, ages, and body compositions.
9. Additional studies are needed to validate the findings of the current study and provide further evidence for the use of ISWT-T as an alternative to ISWT in cases of physical space limitation or the need for physical distancing, such as during pandemics like COVID-19.
