Prediction of Exercise Capacity and Training Prescription from the 6-Minute Walk Test and Rating of Perceived Exertion

The impact of working night shifts on cardiac autonomic nervous regulation during the six-minute walk test in nurses

BACKGROUND

Clinical nurses frequently face the necessity of working night shifts, often with insufficient opportunities for timely sleep recovery, which may negatively impact autonomic nervous system regulation. The aim of this study was to evaluate changes in heart rate variability (HRV) after the six-minute walk test (6MWT) in nurses post-night shift and to explore the impact of night shift work on cardiac autonomic regulation.

METHODS

Thirty-five female nurses, with a mean age of 28.7 years (range 21.0-37.0 years), participated in this study. On the first and second mornings after a night shift, the nurses performed the 6MWT. During the test, electrocardiogram (ECG) signals, blood pressure, and walking distance were recorded simultaneously.

RESULTS

Compared with the second postshift morning, on the first postshift morning, nurses presented higher ratings of perceived exertion (RPE), higher Borg scale scores, and a slower pulse rate before and after the 6MWT but covered a shorter walking distance. Additionally, HRV indicators such as the SDNN, RMSSD, pNN50, TP, VLF, LF, and HF were all higher on the first postshift morning. Regarding the amplitude of cardiac autonomic nervous regulation, variations in the RMSSD and pNN50 were both greater during the 6MWT on the first postshift morning, although there was no significant difference in post-6MWT recovery.

CONCLUSIONS

Night shifts appear to increase the activity of the autonomic nervous system in nurses on the first postshift morning and exert a greater inhibitory effect on parasympathetic activity during the 6MWT. Therefore, it is important to ensure timely recovery sleep and improve autonomic regulation after working night shifts.

KEYWORDS

Heart rate variability; Night shift; Autonomic nervous system; Six-minute walk test; Nurses.

TRIAL REGISTRATION

This study was retrospectively registered in the Clinicaltrials.gov. Registration Date: August 1, 2024.

CLINICALTRIALS

gov ID: NCT06542510.

2023 TAMIS/TSOC/TACVPR Consensus Statement for Patients with Acute Myocardial Infarction Rehabilitation

Cardiac rehabilitation is a comprehensive intervention recommended in international and Taiwanese guidelines for patients with acute myocardial infarction. Evidence supports that cardiac rehabilitation improves the health-related quality of life, enhances exercise capacity, reduces readmission rates, and promotes survival in patients with cardiovascular disease. The cardiac rehabilitation team is comprehensive and multidisciplinary. The inpatient, outpatient, and maintenance phases are included in cardiac rehabilitation. All patients admitted with acute myocardial infarction should be referred to the rehabilitation department as soon as clinically feasible. Pre-exercise evaluation, including exercise testing, helps physicians identify the risks of cardiac rehabilitation and organize appropriate exercise prescriptions. Therefore, the Taiwan Myocardial Infarction Society (TAMIS), Taiwan Society of Cardiology (TSOC), and Taiwan Academy of Cardiovascular and Pulmonary Rehabilitation (TACVPR) address this consensus statement to assist healthcare practitioners in performing cardiac rehabilitation in patients with acute myocardial infarction.

Optimal management of patients after acute coronary syndrome

Patients with clinically established atherosclerotic cardiovascular disease are at a very high risk of recurrent cardiovascular events. An adequate management of risk factors and the implementation of healthy behaviours significantly decrease the risk of unfavourable clinical outcomes and future cardiovascular events, including death. Patients discharged after an acute coronary syndrome should be managed according to their individual risk level in order to ensure the appropriate treatment. Nevertheless, care pathways should also take into consideration the available resources and the logistical/structural aspects. In this setting, cardiac rehabilitation is prosed as a multidisciplinary approach to improving daily function and reducing cardiovascular risk factors. The organization of a network with the involvement of different medical and non-medical figures is essential to ensure successful outcomes and expected cost-effectiveness.

Exercise Evaluation and Prescription-Second Edition

In the first volume of "Exercise Evaluation and Prescription" in the Journal of Functional Morphology and Kinesiology [...].

Cardiorespiratory Fitness in the Prevention and Management of Cardiovascular Disease

Cardiovascular disease (CVD) is the leading cause of death among adults in the U.S. and elsewhere. Variation in the presence, severity, and control of major modifiable risk factors accounts for much of the variation in CVD rates worldwide. Cardiorespiratory fitness (CRF) reflects the integration of ventilation, circulation, and metabolism for the delivery and utilization of oxygen in support of dynamic aerobic physical activity. The gold standard measure of CRF is maximal oxygen uptake. Because the primary factor underlying differences in this measure between individuals is maximal cardiac output, it can serve as a clinical indicator of cardiac function. Higher CRF is associated with favorable levels of major CVD risk factors, lower prevalence and severity of subclinical atherosclerosis, and lower risks of developing both primary and secondary clinical CVD events. The beneficial associations between CRF and CVD are seen in women and men, older and younger adults, in those with multiple coexisting risk factors or prior diagnosis of CVD. Exercise training and regular physical activity of at least moderate intensities and volumes improves CRF in adults, and improvements in CRF are associated with lower risks of subsequent CVD and mortality. Routine assessment of CRF in primary care settings could enhance individual-level CVD risk assessment and thereby guide implementation of appropriate measures to prevent future clinical events.

Oxygen Saturation Behavior by Pulse Oximetry in Female Athletes: Breaking Myths

The myths surrounding women’s participation in sport have been reflected in respiratory physiology. This study aims to demonstrate that continuous monitoring of blood oxygen saturation during a maximal exercise test in female athletes is highly correlated with the determination of the second ventilatory threshold (VT2) or anaerobic threshold (AnT). The measurements were performed using a pulse oximeter during a maximum effort test on a treadmill on a population of 27 healthy female athletes. A common behavior of the oxygen saturation evolution during the incremental exercise test characterized by a decrease in saturation before the aerobic threshold (AeT) followed by a second significant drop was observed. Decreases in peripheral oxygen saturation during physical exertion have been related to the athlete’s physical fitness condition. However, this drop should not be a limiting factor in women’s physical performance. We found statistically significant correlations between the maximum oxygen uptake and the appearance of the ventilatory thresholds (VT1 and VT2), the desaturation time, the total test time, and between the desaturation time and the VT2. We observed a relationship between the desaturation time and the VT2 appearance. Indeed, a linear regression model between the desaturation time and the VT2 appearance can predict 80% of the values in our sample. Besides, we suggest that pulse oximetry is a simple, fairly accurate, and non-invasive technique for studying the physical condition of athletes who perform physical exertion.

Is the Clinical Delivery of Cardiac Rehabilitation in an Australian Setting Associated with Changes in Physical Capacity and Cardiovascular Risk and Are Any Changes Maintained for 12 Months?

Long-term maintenance of changes in cardiovascular risk factors and physical capacity once patients leave the supervised program environment have not previously been reported. This study investigated the changes in physical capacity outcomes and cardiovascular risk factors in an Australian cardiac rehabilitation setting, and the maintenance of changes in these outcomes in the 12 months following cardiac rehabilitation attendance. Improvements in mean (95% CI) cardiorespiratory fitness (16.4% (13.2–19.6%), p < 0.001) and handgrip strength (8.0% (5.4–10.6%), p < 0.001) were observed over the course of the cardiac rehabilitation program, and these improvements were maintained in the 12 months following completion. Waist circumference (p = 0.003) and high-density lipoprotein cholesterol (p < 0.001) were the only traditional cardiovascular risk factors to improve during the cardiac rehabilitation program. Vigorous-intensity aerobic exercise was associated with significantly greater improvements in cardiorespiratory fitness, Framingham risk score, and waist circumference in comparison to moderate-intensity exercise. An increase in the intensity of the exercise prescribed during cardiac rehabilitation in Australia is recommended to induce larger improvements in physical capacity outcomes and cardiovascular risk. A standardized exercise test at the beginning of the rehabilitation program is recommended to facilitate appropriate prescription of exercise intensity.