Physical activity, adiponectin, and cardiovascular structure and function

Relationship between objectively measured physical activity and subclinical cardiovascular disease: a systematic review

Introduction

The association of physical activity (PA) with subclinical cardiovascular disease (CVD) is unclear. Clarifying this relationship may inform cardiovascular prevention strategies.

Methods

We performed a systematic review (CRD42021226089) using Medline, Embase, CINAHL and Cochrane (1 January 2000 to 1 September 2023). Studies published with adult populations exploring the relationship between objectively measured PA and subclinical CVD were included. Subclinical CVD was assessed using: ankle-brachial index (ABI); arterial stiffness; carotid artery disease; coronary artery atherosclerosis; endothelial function; and measures of cardiac structure and function. The Risk Of Bias In Non-randomised Studies - of Interventions (ROBINS-I) and Cochrane Risk of Bias tools were used for quality review.

Results

Of 68 included studies, most supported an inverse relationship between PA and subclinical CVD. Arterial stiffness was the most common outcome (n=40), and 33 studies suggested that less sedentary behaviour (SB), increased PA and/or higher intensity PA was associated with less arterial stiffness. Ten studies of carotid artery disease (total n=18), six of endothelial function (n=10), two of coronary artery disease (n=3) and all of ABI (n=6) suggested that PA or less SB is associated with less subclinical disease. Five studies assessing cardiac structure/function (n=6) suggested alterations in structure/function with PA.

Conclusions

PA reduces the risk of CVD events, and this systematic review demonstrates that some of the benefits may be mediated by an inverse association between PA and subclinical CVD. Interventions to increase PA are important for CVD prevention, so we provide a comprehensive overview of which surrogate outcome measures may be most useful to assess future CVD prevention interventions.

PROSPERO registration number

CRD42021226089.

Is Stiffness Parameter β Useful for the Evaluation of Atherosclerosis?~ Its Clinical Implications, Limitations, and Future Perspectives ~

Atherosclerosis comprises two components, atherosis and sclerosis, characterized by morphological wall thickening and functional stiffening, respectively, of the arterial wall. In recent years, much interest has been directed to the role of functional changes in large arteries, i.e., increased stiffness or decreased elasticity, on the development of cardiovascular diseases. In fact, the clinical evaluation of arterial stiffness is increasingly performed in patients with cardiovascular risk factors. Local arterial stiffness is measured using an ultrasound technique implemented with an echo-tracking system at the common carotid and femoral arteries. Several indices of local arterial stiffness are obtained by ultrasound, among which stiffness parameter β is unique because it is the least affected by blood pressure at the time of measurement. Evidence from cross-sectional studies indicates that increased stiffness parameter β is associated with a number of cardiovascular risk factors, such as older age, smoking, insufficient physical activity, hypertension, obesity, metabolic syndrome, insulin resistance, type 2 diabetes, chronic kidney disease, and comorbid cardiovascular disease. Results from several prospective observational studies also suggest that carotid stiffness parameter β is a useful surrogate marker of cardiovascular events and/or mortality, although the results differ depending on the characteristics of the study subjects. Furthermore, several interventional studies have shown that carotid stiffness parameter β improved after lifestyle modification or drug treatment. In this review, we summarize the current evidence of stiffness parameter β of the carotid artery and discuss its clinical implications as a marker of vascular health or as a predictor of cardiovascular outcomes.

The physiological benefits of sitting less and moving more: Opportunities for future research

Sedentary behavior (SB) and physical activity (PA) are important risk factors of cardiovascular disease morbidity and mortality. In addition to increasing the amount of moderate-to-vigorous PA (MVPA), the current PA guidelines recommend that adults should reduce SB, or any waking activity performed while sitting, reclining, or lying, with low energy expenditure. While mounting evidence has emphasized the benefits of increasing MVPA, little has focused on the effect of SB on health. Therefore, this review discusses the pathophysiological effects of SB and the potential physiological benefits of reducing/breaking up SB at the levels below the current guidelines for PA. Such knowledge is important, given that the majority of the United States population performs insufficient or no MVPA and is at high risk of being negatively impacted by SB. Interventions targeting sedentary time, such as breaking up SB by standing and moving, may be safe, feasible, and applicable to execute daily for a wide range of the population. This review also discusses the importance of monitoring SB in the era of the coronavirus disease 2019 (COVID-19) pandemic and the clinical implications of sitting less and moving more.

Effects of Hypobaric Hypoxia on Endothelial Function and Adiponectin Levels in Airforce Aviators

Background: Hypobaric hypoxia (HH) increases the risk of high altitude-related illnesses (HARI). The pathophysiological mechanism(s) involved are still partially unknown. Altered vascular reactivity as consequence of endothelial dysfunction during HH might play a role in this phenomenon. Adiponectin exerts protective effect on cardiovascular system since it modulates NO release, antagonizing endothelial dysfunction. Aims of this study, performed in a selected population of airforce aviators, were (1) to investigate whether exposure to acute HH might be associated with endothelial dysfunction and (2) to evaluate whether adiponectin might be involved in modulating this phenomenon. Methods: Twenty aviators were exposed to acute HH in a hypobaric chamber by simulating altitude of 8000 and then 6000 m for 2 hours. Vascular reactivity was evaluated by the EndoPAT test immediately before and after the HH; salivary and blood adiponectin levels were measured. Results: EndoPAT performed immediately after HH divided pilots in two groups: 12 pilots with preserved vascular reactivity and 8 pilots with reduction of vascular reactivity, indicating that HH exposure might cause endothelial dysfunction. Salivary and blood adiponectin levels increased post-HH in a time-dependent manner in all aviators, but the significant increase was observed only in those with preserved vascular reactivity suggesting that HH stimulated release of adiponectin that, in turn, by exerting a protective effect, might reduce endothelial dysfunction. Conclusions: Acute HH may cause endothelial dysfunction due, at least in part, to reduced release of adiponectin. This phenomenon might be involved in pathophysiology of HARI.

A Review on the Role of Irisin in Insulin Resistance and Type 2 Diabetes Mellitus

Irisin is a novel hormone like polypeptide that is cleaved and secreted by an unknown protease from fibronectin type III domain-containing protein 5 (FNDC5), a membrane- spanning protein and which is highly expressed in skeletal muscle, heart, adipose tissue, and liver. Since its discovery in 2012, it has been the subject of many researches due to its potent physiological role. It is believed that understanding irisin’s function may be the key to comprehend many diseases and their development. Irisin is a myokine that leads to increased energy expenditure by stimulating the ‘browning’ of white adipose tissue. In the first description of this hormone, increased levels of circulating irisin, which is cleaved from its precursor fibronectin type III domain-containing protein 5, were associated with improved glucose homeostasis by reducing insulin resistance. Irisin is a powerful messenger, sending the signal to determine the function of specific cells, like skeletal muscle, liver, pancreas, heart, fat and the brain. The action of irisin on different targeted tissues or organs in human being has revealed its physiological functions for promoting health or executing the regulation of variety of metabolic diseases. Numerous studies focus on the association of irisin with metabolic diseases which has gained great interest as a potential new target to combat type 2 diabetes mellitus and insulin resistance. Irisin is found to improve insulin resistance and type 2 diabetes by increasing sensitization of the insulin receptor in skeletal muscle and heart by improving hepatic glucose and lipid metabolism, promoting pancreatic β cell functions, and transforming white adipose tissue to brown adipose tissue. This review is a thoughtful attempt to summarize the current knowledge of irisin and its effective role in mediating metabolic dysfunctions in insulin resistance and type 2 diabetes mellitus.

Adiponectin, Leptin and Objectively Measured Physical Activity in Adults: A Narrative Review

The objective of this study was to compile and analyse existing scientific evidences reporting the effects of objectively measured physical activity on the levels of adiponectin and leptin. Articles related to the effects of objectively measured physical activity on the levels of adiponectin and leptin were searched from the Medline and PubMed databases. The search was limited to 'objectively measured' physical activity, and studies that did not objectively measure the physical activity were excluded. Only English articles were included in the search and review. A total of 18 articles encompassing 2,026 respondents met the inclusion criteria. The eligible articles included all forms of evidence (e.g., cross-sectional and intervention). Seventeen and 11 studies showed the effects of objectively measured physical activity on adiponectin and leptin, respectively. Five and four cross-sectional studies showed the effects of objectively measured physical activity on adiponectin and leptin, respectively. Two out of five studies showed a weak to moderate positive association between adiponectin and objectively measured physical activity, while three out of four studies showed a weak to moderate inverse association between leptin and objectively measured physical activity. For intervention studies, six out of 12 studies involving adiponectin and five out of seven studies involving leptin showed a significant effect between the proteins and objectively measured physical activity. However, a definitive conclusion could not be drawn due to several methodological flaws in the existing articles and the acute lack of additional research in this area. In conclusion, the existing evidences are encouraging but yet not compelling. Hence, further well-designed large trials are needed before the effectiveness of objectively measured physical activity in elevating adiponectin levels and in decreasing leptin levels could be strongly confirmed.

Irisin, an exercise-induced myokine as a metabolic regulator: an updated narrative review

Irisin, as a new hormone-like myokine, is discovered in the presence of exercise-induced peroxisome proliferator-activated receptor gamma coactivator-1-alpha (PGC-1α). Which substance plays an important role in energy metabolism in each organ in the body and the regulation of metabolic diseases such as obesity and diabetes. The finding of irisin can contribute to the exploration of the novel and effective therapeutic targets or therapeutic strategies of these metabolic diseases or metabolism-associated health issues. To date, little is known regarding the functions and regulatory mechanisms of irisin with respect to metabolic diseases or metabolism-associated health issues. In this narrative review article, we systematically introduce its structural characteristics, production and distribution in tissues and organs, and the regulation and corresponding mechanisms for metabolic diseases or metabolism-associated health issues of irisin. Meanwhile, its future prospects and the development of irisin-related products for the promotion of human health have also been proposed, which will benefit future research and application of irisin. Copyright © 2015 John Wiley & Sons, Ltd.

Higher physical activity is associated with lower aortic stiffness but not with central blood pressure: the ADDITION-Pro Study

Physical activity is associated with reduced cardiovascular disease risk. However, improvements in conventional risk factors due to physical activity do not explain its full benefit. Therefore, we examined associations of objectively measured physical activity energy expenditure and intensity with central hemodynamics to provide new insight into the link between physical activity and cardiovascular disease. We analyzed data from 1816 Danes (median age: 66 years) without cardiovascular disease. Physical activity was estimated using combined accelerometry and heart rate monitoring. Aortic stiffness was assessed by applanation tonometry, as aortic pulse wave velocity, and central blood pressure was estimated from radial waveforms. Associations between physical activity energy expenditure and central hemodynamics were examined by linear regression. Furthermore, the consequence of substituting 1 hour sedentary behavior with 1 hour light or moderate-to-vigorous physical activity on central hemodynamics was examined. Median physical activity energy expenditure was 28.0 kJ/kg/d (IQR: 19.8; 38.7). A 10 kJ/kg/d higher energy expenditure was associated with 0.75% lower aortic pulse wave velocity (CI: -1.47; -0.03). Associations with central systolic blood pressure and central pulse pressure were not statistically significant. We observed no difference in central hemodynamics when substituting 1 hour sedentary behavior with 1 hour light or moderate-to-vigorous physical activity. In this relatively inactive population, higher physical activity energy expenditure was associated with lower aortic stiffness, while there was no statistically significant association between substitution of activity intensity and central hemodynamics. This suggests that lower aortic stiffness is one of a number of health benefits attributed to higher habitual physical activity.

Adiponectin is not associated with blood pressure in normotensives and untreated hypertensives with normal kidney function

The role of adiponectin in hypertension is still a matter of debate. Obtained conflicting results could be mostly explained with diversity of subjects included in different studies. Our aim was to analyze association of adiponectin with blood pressure (BP) in a group of normotensive and untreated hypertensive subjects. Participants (N=257) were selected from a random sample of 2487 subjects enrolled in an observational cross-sectional study. Subjects with diabetes and chronic kidney diseases were excluded. BP was measured using Omron M6 device following ESH/ESC guidelines. Adiponectin concentration was determined by ELISA. There were no differences in adiponectin values (mg/L) between hypertensives and normotensives (median 9.75; iqr: 7.44-17.88 vs 11.35; iqr: 7.43-12.63; P=0.17). On univariate linear regression adiponectin was not associated with systolic or diastolic BP (P>0.05). Furthermore, multivariate analysis did not show significant contribution of log-transformed adiponectin either to systolic (β=-0.040; P=0.43) or diastolic BP (β=0.066; P=0.33). In our group of normotensives and untreated hypertensives with normal kidney function adiponectin was not associated with BP even after adjustment for other risk factors. Our results and conclusions should not be extrapolated to subjects with other characteristics.

Myocardial deformational adaptations to different forms of training: a real-time three-dimensional speckle tracking echocardiographic study

The hemodynamic load due to physical activity leads to structural and functional cardiac adaptations known as "Athlete's heart". We aimed to compare myocardial performance in different groups of trained athletes by means of 3D echocardiography and 3D speckle tracking echocardiography (3D-STE). 66 athletes [26 strength-trained athletes (STA) and 40 endurance athletes (ETA)] were prospectively enrolled. A control group of 40 sedentary subjects (sedentary group) was also included. All subjects underwent both standard and 3D evaluation of left ventricular (LV) function including 3D-STE. Left ventricular mass indexed for body surface area, LV end-diastolic (LV Dd) thickness of interventricular septum and posterior wall thickness mean values were significantly increased in athletes (p < 0.001, p < 0.01 and p < 0.001, respectively). LV diastolic diameter index had a significantly higher mean value in ETA in respect to sedentary group (p = 0.001). Despite a preserved mean value of LV ejection fraction (LV EF) in all the groups, subjects in STA group showed a significant reduction of strain in the longitudinal, radial and circumferential directions (p < 0.05 for all). Area strain mean value was also reduced in STA group (p < 0.01). In the overall population, an inverse relationship between longitudinal strain and LV Dd index (r = -0.260, p = 0.008), the E/A ratio (r = -0.249, p = 0.010) and the E' velocity (r = -0.259, p = 0.009) has been identified. Sport-specific patterns of ventricular morphological and functional remodeling are present in athletes performing different kinds of training. 3D-STE is a useful and feasible echocardiographic technique for the assessment of sport-specific pattern of deformational adaptations.

Peak stepping cadence is associated with leg vascular compliance in young adults

OBJECTIVES

To test the hypothesis that volume or intensity of daily ambulatory activity would associate with greater large artery compliance in healthy untrained adults.

DESIGN

Cross-sectional study.

METHODS

Forty-five recreationally active young adults (22 ± 3 yr, 51% women) wore an accelerometer for 5.3 ± 1.3 days for determination of average daily steps (volume) and 30-min peak stepping cadence (intensity; average steps per min for the 30 highest min in a day). Arterial compliance of the common carotid artery, superficial femoral artery (SFA), and popliteal artery was estimated using Doppler ultrasound. Data were analyzed using correlational analysis and analysis of covariance.

RESULTS

Average daily steps and peak stepping cadence was 8957 ± 3422 steps per day and 97 ± 24 steps per min, respectively. Weight was the main independent predictor of daily steps (r(2) = 0.13, p = 0.01) and peak stepping cadence (r(2) = 0.17, p<0.01). After adjusting ambulatory activity for weight, SFA compliance was positively correlated with peak stepping cadence (r = 0.53, p<0.01) but not with daily steps (r = 0.23, p > 0.05). No other correlations were found between ambulatory activity and carotid or popliteal artery compliance (p>0.05). Adults with peak stepping cadence ≥ 102 steps per min had greater carotid (1.26 ± 0.08 vs. 1.57 ± 0.09 mm(2) kPa(-1); p = 0.01) and SFA compliance (0.43 ± 0.03 vs. 0.54 ± 0.03 mm(2) kPa(-1); p = 0.04) than adults with lower stepping cadence.

CONCLUSIONS

"Brisk" stepping cadence during daily ambulation is associated with greater leg vascular compliance. These results support the promotion of accumulating 30 min of "brisk" walking per day as a strategy to improve vascular health.