Evaluating current assessment techniques of cardiorespiratory fitness.

INTRODUCTION: Considerable and convincing global data from cohorts across the health spectrum (i.e. apparently healthy to known disease) indicate that cardiorespiratory fitness (CRF) is a major predictor of overall and cardiovascular disease (CVD)-survival, seemingly with greater prognostic resolution compared to other traditional CVD risk factors. Therefore, the assessment of CRF in research and clinical settings is of major importance. AREAS COVERED: In this manuscript, we review the technology of measuring CRF assessed by the 'gold standard,' cardiopulmonary exercise testing (CPET), as well as with various other methods (e.g. estimated metabolic equivalents, 6-minute walk tests, shuttle tests, and non-exercise equations that estimate CRF), all of which provide significant prognostic information for CVD- and all-cause survival. The literature through May 2024 has been cited. EXPERT OPINION: The promotion of physical activity in efforts to improve levels of CRF is needed throughout the world to improve lifespan and, more importantly, healthspan. The routine assessment of CRF should be considered a vital sign that is routinely assessed in clinical practice.

How to interpret a cardiorespiratory fitness assessment - Key measures that provide the best picture of health, disease status and prognosis.

Graded exercise testing is a widely accepted tool for revealing cardiac ischemia and/or arrhythmias in clinical settings. Cardiopulmonary exercise testing (CPET) measures expired gases during a graded exercise test making it a versatile tool that helps reveal underlying physiologic abnormalities that are in many cases only present with exertion. It also characterizes one's health status and clinical trajectory, informs the therapeutic plan, evaluates the efficacy of therapy, and provides submaximal and maximal information that can be used to tailor an exercise intervention. Practitioners can also modify the mode and protocol to allow individuals of all ages, fitness levels, and most disease states to perform a CPET. When used to its full potential, CPET can be a key tool used to optimize care in primary and secondary prevention settings.

The Impact of Light Physical Activity, Sedentary Behavior and Cardiorespiratory Fitness in Extending Lifespan and Healthspan Outcomes: How Little is Still Significant? A Narrative Review.

To describe the relationship between mortality and measures of low intensity physical activity (LIPA) as well as sedentary behavior (SB), and cardiorespiratory fitness (CRF). Study selection was performed through multiple database searches from January 1, 2000 until May 1, 2023. Seven LIPA studies, 9 SB studies, and 8 studies CRF studies were selected for primary analysis. LIPA and non-SB follow a reverse J shaped curve with mortality. The greatest benefits occur initially, and the rate of mortality reduction slows with increasing physical activity. Increasing CRF reduces mortality although the dose response curve is uncertain. For special populations such as individuals with, or at high risk of developing cardiovascular disease the benefit from exercise is heightened. LIPA, decreased SB and higher CRF lead to reductions in mortality and improved quality of life. Individualized counseling on the benefits of any amount of physical activity may increase compliance and serve as a starting point for lifestyle modifications.

The Impact of COVID-19 on the Social Determinants of Cardiovascular Health.

Cardiovascular disease is the leading noncommunicable disease and cause of premature mortality globally. Despite well established evidence of a cause-effect relationship between modifiable lifestyle behaviours and the onset of risk of chronic disease, preventive approaches to curtail increasing prevalence have been ineffective. This has undoubtedly been exacerbated by the response to COVID-19, which saw widespread national lockdowns implemented to reduce transmission and alleviate pressure on strained health care systems. A consequence of these approaches was a well documented negative impact on population health in the context of both physical and mental well-being. Although the true extent of the impact of the COVID-19 response on global health has yet to be fully realised or understood, it seems prudent to review effective preventative and management strategies that have yielded positive outcomes across the spectrum (ie, from individual to society). There is also a clear need to heed lessons learned from the COVID-19 experience in the power of collaboration and how this can be used in the design, development, and implementation of future approaches to address the longstanding burden of cardiovascular disease.

What has cardiac rehabilitation looked like in the COVID-19 pandemic: Lessons learned for the future.

The global coronavirus disease 2019 (COVID-19) pandemic prompted widespread national shutdown, halting or dramatically reducing the delivery of non-essential outpatient services including cardiac rehabilitation (CR). Center-based CR services were closed for as few as two weeks to greater than one year and the uncertainty surrounding the duration of the lockdown phase prompted programs to consider programmatic adaptations that would allow for the safe and effective delivery of CR services. Among the actions taken to accommodate in person CR sessions included increasing the distance between exercise equipment and/or limiting the number of patients per session. Legislative approval of reimbursing telehealth or virtual services presented an opportunity to reach patients that may otherwise have not considered attending CR during or even before the pandemic. Additionally, the considerable range of symptoms and infection severity as well as the risk of developing long lasting, debilitating symptoms has complicated exercise recommendations. Important lessons from publications reporting findings from clinical settings have helped shape the way in which exercise is applied, with much more left to discover. The overarching aim of this paper is to review how programs adapted to the COVID-19 pandemic and identify lessons learned that have positively influenced the future of CR delivery.

Long-Term Maintenance of Cardiorespiratory Fitness Gains After Cardiac Rehabilitation Reduces Mortality Risk in Patients With Multimorbidity.

PURPOSE: The objective of this study was to characterize the impact of multimorbidity and cardiorespiratory fitness (CRF) on mortality in patients completing cardiac rehabilitation (CR). METHODS: This cohort study included data from patients with a history of cardiovascular disease (CVD) completing a 12-wk CR program between January 1996 and March 2016, with follow-up through March 2017. Patients were stratified by the presence of multimorbidity, which was defined as having a diagnosis of ≥2 noncommunicable diseases (NCDs). Cox regression analyses were used to evaluate the effects of multimorbidity and CRF on mortality in patients completing CR. Symptom-limited exercise tests were completed at baseline, immediately following CR (12 wk), with a subgroup completing another test at 1-yr follow-up. Peak metabolic equivalents (METs) were determined from treadmill speed and grade. RESULTS: Of the 8320 patients (61 ± 10 yr, 82% male) included in the analyses, 5713 (69%) patients only had CVD diagnosis, 2232 (27%) had CVD+1 NCD, and 375 (4%) had CVD+≥2 NCDs. Peak METs at baseline (7.8 ± 2.0, 6.9 ± 2.0, 6.1 ± 1.9 METs), change in peak METs immediately following CR (0.98 ± 0.98, 0.83 ± 0.95, 0.76 ± 0.95 METs), and change in peak METs 1 yr after CR (0.98 ± 1.27, 0.75 ± 1.17, 0.36 ± 1.24 METs) were different ( P < .001) among the subgroups. Peak METs at 12 wk and the presence of coexisting conditions were each predictors ( P < .001) of mortality. Improvements in CRF by ≥0.5 METS from baseline to 1-yr follow-up among patients with or without multimorbidity were associated with lower mortality rates. CONCLUSION: Increasing CRF by ≥0.5 METs improves survival regardless of multimorbidity status.

Right Ventricular Contractile Reserve: A Key Metric to Identifying When Cardiorespiratory Fitness Will Improve With Pulmonary Vasodilators.

Cardiorespiratory fitness (CRF) has been proposed as a vital sign for the past several years, supported by a wealth of evidence demonstrating its significance as a predictor of health trajectory, exercise/functional capacity, and the quality of life. According to the Fick equation, oxygen consumption (VO2) is the product of cardiac output (CO) and arterial-venous oxygen difference, with the former being a primary driver of one's aerobic capacity. In terms of the dependence of aerobic capacity on a robust augmentation of CO from rest to maximal exercise, left ventricular (LV) CO has been the historic focal point. Patients with pulmonary arterial hypertension (PAH) or secondary pulmonary hypertension (PH) present with a significantly compromised CRF; as pathophysiology worsens, so too does CRF. Interventions to improve pulmonary hemodynamics continue to emerge and are now a standard of clinical care in several patient populations with increased pulmonary pressures; new pharmacologic options continue to be explored. Improvement in CRF/aerobic capacity has been and continues to be a primary or leading secondary endpoint in clinical trials examining the effectiveness of pulmonary vasodilators. A central premise for including CRF/aerobic capacity as an endpoint is that pulmonary vasodilation will lead to a significant downstream increase in LV CO and therefore peak VO2. However, the importance of right ventricular (RV) CO to the peak VO2 response continues to be overlooked. The current review provides an overview of relevant principles of exercise physiology, approaches to assessing RV contractile reserve and proposals for clinical trial design and subject phenotyping.

Role of BH4 deficiency as a mediator of oxidative stress-related endothelial dysfunction in menopausal women.

Endothelial function (brachial artery flow-mediated dilation [FMD]) is reduced in estrogen-deficient postmenopausal women, mediated, in part, by reduced nitric oxide (NO) bioavailability, secondary to tetrahydrobiopterin (BH4) deficiency and oxidative stress. FMD is increased, but not fully restored, in postmenopausal women after acute intravenous vitamin C (VITC; superoxide scavenger) or oral BH4 supplementation. In vitro studies demonstrate that coadministration of VITC with BH4 prevents endothelial nitric oxide synthase (eNOS) uncoupling and reductions in NO by peroxynitrite. To investigate mechanisms of endothelial dysfunction in women, we assessed the separate and combined effects of VITC and BH4 to determine whether coadministration of VITC + BH4 improves FMD in healthy postmenopausal women (n = 19, 58 ± 5 yr) to premenopausal (n = 14, 36 ± 9 yr) levels, with exploratory testing in perimenopausal women (n = 8, 51 ± 3 yr). FMD was measured during acute intravenous infusions of saline (control) and VITC (∼2-3 g) ∼3 h after a single dose of oral BH4 (KUVAN, 10 mg/kg body wt) or placebo (randomized crossover, separated by ∼1 mo). Under the placebo condition, FMD was reduced in postmenopausal compared with premenopausal women during the saline infusion (5.6 ± 0.7 vs. 11.6 ± 0.9%, P < 0.001) and increased in postmenopausal women during VITC (+3.5 [1.4, 5.6]%, P = 0.001) and acute BH4 (+1.8 [0.37, 3.2]%, P = 0.01) alone. Coadministration of VITC + BH4 increased FMD in postmenopausal women (+3.0 [1.7, 4.3]%, P < 0.001), but FMD remained reduced compared with premenopausal women (P = 0.02). Exploratory analyses revealed that VITC + BH4 did not restore FMD in perimenopausal women to premenopausal levels (P = 0.045). Coadministration of VITC + BH4 does not restore FMD in menopausal women, suggesting that additional mechanisms may be involved.NEW & NOTEWORTHY Endothelial function is reduced across the menopausal stages related to increased oxidative stress associated with estrogen deficiency. In vitro studies demonstrate that coadministration of VITC with BH4 prevents endothelial nitric oxide synthase (eNOS) uncoupling and reductions in NO by peroxynitrite; however, this remains untested in humans. We demonstrate that the coadministration of BH4 + VITC does not restore endothelial function in perimenopausal and postmenopausal women to the level of premenopausal women, suggesting that other mechanisms contribute.

It still takes a village: Advocating healthy living medicine for communities through social justice action.

Countless individuals in the United States continue to experience effects related to the coronavirus disease 2019 (COVID-19) pandemic, such as job/business instability, the breaking down of school systems, isolation, and negative health consequences. There are, however, certain populations and communities that continue to be disproportionately affected, resulting in severe health outcomes, decreased quality of life, and alarmingly high death rates. These populations typically live in historically excluded communities and identify as persons of color. To advance health equity in these communities, healthy living (HL) strategies are paramount. In fact HL Medicine - getting sufficient physical activity, practicing good nutrition, maintaining a healthy body weight, and not smoking, can be a viable solution. Applying these concepts, particularly the promotion of physical activity, through community collaboration can advance the goals of social justice action.

Exercise training in cardiac rehabilitation: Setting the right intensity for optimal benefit.

Cardiac rehabilitation (CR) programs are recommended standard-of-care by all major cardiovascular medicine professional organizations. Exercise training is the cornerstone for CR, with aerobic training being the primary form of training. The benefits of exercise training are multiple; however, improved cardiorespiratory fitness is of utmost importance. Moderate-intensity continuous training, supplemented with resistance training, has traditionally been the most common form of exercise training in CR. This review discusses the role of aerobic exercise training in CR and the importance of effective and personalized exercise prescription for optimized results. We also focus on the benefits and utility of high-intensity interval training across different clinical populations commonly seen in the CR setting.

Defining the importance of stress reduction in managing cardiovascular disease - the role of exercise.

Traditional risk factors for cardiovascular disease (CVD) have long been the focus of preventive strategies. The impact of family stress, depression, anxiety, hostility, pessimism, job strain, social isolation, lack of purpose in life and social support, are well recognized risks for CVD development, however they are under-appreciated in clinical practice guidelines. The purpose of this article is to review the impact of acute and chronic stress on CVD risk, elaborate repositioning in guidelines, with emphasis to approaches for stress reduction. Regular exercise, both aerobic and resistance, leads to better adaptiveness to other types of stress, however, it remains unknown whether the total amount of stress one can receive before negative health effects is unlimited. Evidently, marked reductions in stress related disorders are shown following formal cardiac rehabilitation programs. Attendance of cardiac rehabilitation is highly recommended for the stress-related mortality risk reduction. Innovative approaches to offset the broad challenges that CVD pose, augmented by sustained exposure to stress, are desperately needed, but hindered by a lack of successful population-level interventions that promote lasting change.

The importance of healthy lifestyle behaviors in the prevention of cardiovascular disease.

Cardiovascular disease (CVD) is the leading cause of death globally. Advancements in the treatment of CVD have reduced mortality rates, yet the global burden of CVD remains high. Considering that CVD is still largely a preventable disease, prioritizing preventative measures through healthy lifestyle (HL) behaviors is necessary to lessen the burden of CVD. HL behaviors, such as regular exercise, healthy eating habits, adequate sleep, and smoking cessation, can influence a number of traditional CVD risk factors as well as a less commonly measured risk factor, cardiorespiratory fitness (CRF). It is important to note that cardiac rehabilitation programs, which traditionally have focused on secondary prevention, also emphasize the importance of making comprehensive HL behavior changes. This review discusses preventative measures to reduce the burden of CVD through an increased uptake and assessment of HL behaviors. An overview of the importance of CRF as a risk factor is discussed along with how to improve CRF and other risk factors through HL behavior interventions. The role of the clinician for promoting HL behaviors to prevent CVD is also reviewed.

An Evolving Approach to Assessing Cardiorespiratory Fitness, Muscle Function and Bone and Joint Health in the COVID-19 Era.

Cardiorespiratory fitness (CRF) is now an established vital sign. CRF, along with muscle function and bone and joint health is related to functional independence and a higher quality of life. Wasserman and colleagues proposed a gear model illustrating the integrated role of the respiratory, cardiovascular, and skeletal muscle systems during aerobic exercise; in 2015, a revision to the original model was proposed. Our understanding of the effects and challenges associated with the coronavirus disease 2019 (COVID-19) are rapidly evolving. Initial evidence indicates higher levels of CRF, and muscle function protect individuals infected with COVID-19 from a complicated medical course. Moreover, for those individuals infected with COVID-19, there are initial signs of a reduction in CRF following the initial phase of recovery. We are also gaining an understanding of long COVID syndrome, where individuals who have recovered from the acute phase of viral infection present with lasting symptoms, which include but are not limited to reduced CRF, shortness of breath, and fatigue. Clearly, these individuals will require rehabilitation to restore and/or improve CRF, muscle function, bone and joint health, functional capacity (ie, the ability to perform activities of daily living), and quality of life. The importance of assessing the synergistic function of systems essential to performing activities that require physical exertion is a health care imperative. This graphical narrative provides an update to the gear model initially proposed by Wasserman and updated to a gear and circuit in 2015. External CRF, muscle function, and bone and joint health influencers and an approach to clinical assessment are also introduced.