Blood Pressure Control at Rest and during Exercise in Obese Children and Adults

The damaging duo: Obesity and excess dietary salt contribute to hypertension and cardiovascular disease

Hypertension is a primary risk factor for cardiovascular disease. Cardiovascular disease is the leading cause of death among adults worldwide. In this review, we focus on two of the most critical public health challenges that contribute to hypertension-obesity and excess dietary sodium from salt (i.e., sodium chloride). While the independent effects of these factors have been studied extensively, the interplay of obesity and excess salt overconsumption is not well understood. Here, we discuss both the independent and combined effects of excess obesity and dietary salt given their contributions to vascular dysfunction, autonomic cardiovascular dysregulation, kidney dysfunction, and insulin resistance. We discuss the role of ultra-processed foods-accounting for nearly 60% of energy intake in America-as a major contributor to both obesity and salt overconsumption. We highlight the influence of obesity on elevated blood pressure in the presence of a high-salt diet (i.e., salt sensitivity). Throughout the review, we highlight critical gaps in knowledge that should be filled to inform us of the prevention, management, treatment, and mitigation strategies for addressing these public health challenges.

The Effects of Obesity on the Inflammatory, Cardiovascular, and Neurobiological Responses to Exercise in Older Adults

Obesity with advancing age leads to increased health complications that are involved in various complex physiological processes. For example, inflammation is a critical cardiovascular disease risk factor that plays a role in the stages of atherosclerosis in both aging and obesity. Obesity can also induce profound changes to the neural circuitry that regulates food intake and energy homeostasis with advancing age. Here we discuss how obesity in older adults impacts inflammatory, cardiovascular, and neurobiological functions with an emphasis on how exercise mediates each topic. Although obesity is a reversible disorder through lifestyle changes, it is important to note that early interventions are crucial to prevent pathological changes seen in the aging obese population. Lifestyle modifications such as physical activity (including aerobic and resistance training) should be considered as a main intervention to minimize the synergistic effect of obesity on age-related conditions, such as cerebrovascular disease.

Individuals with a previous symptomatic COVID-19 infection have altered heart rate and blood pressure variability during acute exercise

Introduction: As the number of COVID-19 cases begin to diminish it is important to turn our attention to any long-term issues that may be associated with a prior infection. Cardiovascular defects have been noted following prior SARS-CoV-2 infections. However, less is known about how a previous infection alters the cardiovascular response to exercise. Further, differences may exist during exercise between previously SARS-CoV-2 positive individuals who had symptoms (symptomatic) relative to those who did not have symptoms (asymptomatic). We hypothesized that previously symptomatic (S) COVID-19 recoveries have an altered cardiovascular response to acute exercise relative to both control (CON; never infected), and previously COVID-19 positive asymptomatic (AS) individuals. Methods: Twenty-seven subjects (CON = 9; AS = 9; S = 9) underwent 30 min of submaximal treadmill exercise. During exercise, blood pressure was recorded on the brachial artery every 5 min and 3-lead electrocardiography was measured continuously. Indirect indicators of autonomic nervous system health: heart rate variability and blood pressure variability were measured during each session. Baseline mean arterial pressure (MAP) was taken prior to exercise in seated, standing and supine positions. Results: Blood pressure was similar (p > 0.05) amongst all three groups. There were no differences between average heart rate (HR; CON = 104 ± 4 BPM vs AS = 118 ± 6 BPM vs. S = 112 ± 3 BPM), mean arterial pressure (MAP; CON = 108 ± 4 mmHg vs. AS = 105 ± 13 mmHg vs. S = 108 ± 7 mmHg) or oxygen consumption (VO₂) between groups during a bout of exercise. However, the standard deviation of the inter beat intervals of normal sinus beats, a measure of heart rate variability (HRV) (CON = 138 ± 2.8 m vs. AS = 156 ± 6 m vs. S = 77.7 ± 11 m; p < 0.05) and blood pressure variability (BPV; CON = 5.18 ± 1.1 vs. AS = 12.1 ± 0.88 mmHg vs. S = 10.2 ± 10.7 mmHg; p < 0.05) were different in our S group. Further, when HRV was assessed in the frequency domain the very low frequency was different during exercise in the S group relative to the other groups. Discussion: Collectively, these data suggest that a previous symptomatic SARS-CoV-2 infection may alter heart rate and blood pressure regulation during exercise.

Cardiac autonomic disturbance following resistance and sprint-interval exercises in non-obese and obese young men

This study examined the alterations of heart rate variability (HRV) following iso-duration resistance (RES) and sprint-interval (SIE) exercises by comparing with that of non-exercise control (CON) in 14 non-obese (NOB) and 15 obese (OB) young men. Time and frequency domain measures as well as non-linear metrics of HRV were assessed before and immediately after exercise, and during every 20 min until 120 min post exercise. The variables during the first 4 hrs of actual sleep time at night, and the period of 12-14 hrs post exercise were also measured. All trials were scheduled at 20:00. It was found that RES and SIE attenuated the HRV in both NOB and OB (P <0.05), and the attenuated HRV restored progressively during subsequent recovery. Although the changes in HRV indices among various time points during the recovery period and its interaction across RES, SIE and CON were not different between NOB and OB, the restoration of the declined HRV indices to corresponding CON level in the two exercise trials in OB appeared to be sluggish in relative to NOB. Notwithstanding, post-exercise HRV that recorded during actual sleep at night and during 12-14 hrs apart from exercise were unvaried among the three trials in both groups (P>0.05). These findings suggest that obesity is likely to be a factor hindering the removal of exercise-induced cardiac autonomic disturbance in young men. Nonetheless, the declined HRV following both the RES and SIE protocols were well restored after a resting period of ~10 hrs regardless of obesity. The study was registered at ISRCTN as DOI:10.1186/ISRCTN88544091.

Responses of different functional tests in candidates for bariatric surgery and the association with body composition, metabolic and lipid profile

Individuals with obesity can have metabolic disorders and may develop impairments that affect the ability to exercise. The maximal incremental cardiopulmonary exercise test is widely used to assess functional capacity. However, submaximal tests such as the two-minute step test (2MST) and the six-minute walk test (6MWT) also allow this assessment. We propose to analyze whether body composition, metabolic and lipid profile influence the maximal and submaximal performance, and investigate these variables in response to different functional tests. Forty-four individuals with obesity, aged 18–50 years, underwent analysis of body composition, metabolic and lipid profile, incremental treadmill test (ITMT), 6MWT, and 2MST. One-way ANOVA, Pearson or Spearman correlation, and Stepwise multiple linear regression analysis were performed. ITMT induced a greater metabolic, ventilatory, cardiovascular, and perceived exertion demand when compared to the 6MWT and 2MST (p < 0.05). In addition, 2MST elicited a higher chronotropic (HR) and metabolic (V̇O₂) demand when compared to the 6MWT (p < 0.05). Significant correlations were found between tests and body composition, metabolic and lipid profile. Fat mass and low-density lipoprotein can explain 30% of the V̇O₂ variance in the ITMT; and fat mass, glucose, and performance in the 2MST can explain 42% of the variance of the distance walked in the ITMT. Obesity and its metabolic impairments are capable of influencing responses to exercise. ITMT generated greater demand due to the high stress imposed, however, 2MST demanded greater metabolic and chronotropic demand when compared to the 6MWT.

Perceived Barriers to Blood Flow Restriction Training

Blood flow restriction (BFR) training is increasing in popularity in the fitness and rehabilitation settings due to its role in optimizing muscle mass and strength as well as cardiovascular capacity, function, and a host of other benefits. However, despite the interest in this area of research, there are likely some perceived barriers that practitioners must overcome to effectively implement this modality into practice. These barriers include determining BFR training pressures, access to appropriate BFR training technologies for relevant demographics based on the current evidence, a comprehensive and systematic approach to medical screening for safe practice and strategies to mitigate excessive perceptual demands of BFR training to foster long-term compliance. This manuscript attempts to discuss each of these barriers and provides evidence-based strategies and direction to guide clinical practice and future research.

Effect of obesity on cardiovascular responses to submaximal treadmill exercise in adult males

Context:

Obesity is a major risk factor for chronic diseases. Abnormal changes in cardiovascular responses to exercise indicate the alteration in autonomic activity in obese.

Aims:

To assess and compare the cardiovascular parameters before and after exercise among obese and nonobese adult males.

Subjects and Methods:

Thirty each obese and normal-weight males between the age group 18-45 years were selected as cases and controls, respectively. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), corrected QT intervals were measured before and after submaximal treadmill exercise (QT and QTc) were done according to Bruce protocol. HR, SBP, DBP, MAP, QT, and QTc were also measured during passive recovery at 1 min and 5 min after exercise.

Statistical Analysis Used:

One-way analysis of variance and t-test were used to assess changes before and after exercise.

Results:

Resting HR was significantly higher in obese when compared to nonobese (P < 0.05). SBP, DBP, MAP, QT, and QTc were significantly higher in obese when compared to nonobese (P < 0.001). Immediately after exercise HR, SBP, DBP, MAP, QT, and QTc were significantly higher in obese when compared to nonobese (P < 0.001) 1 min after exercise.

Conclusions:

Obese individuals had elevated resting cardiovascular parameters and showed increased responses to steady exercise which could be due to alteration in autonomic functions with sympathetic hyperactivity. Delayed rate of decrease in HR and BP after exercise was also observed in obese, which indicates that they are at risk of developing cardiovascular diseases.

The Role of Exercise in Patients with Obesity and Hypertension

PURPOSE OF REVIEW

This review sought to evaluate the role of exercise in patients with obesity and comorbid hypertension, with a focus on contemporary literature (since January 2015).

RECENT FINDINGS

No reviews have included patients classified with both obesity and hypertension and there is a paucity of randomised controlled trials examining the benefits of exercise in this population. Moreover, just one of 19 reviews examining the role of exercise on blood pressure included studies that met pre-defined inclusion criterion for hypertension, although seven conducted subgroup analyses stratified by mean baseline blood pressure. These demonstrated significantly larger reductions in blood pressure in hypertensive than pre-hypertensive and normotensive samples. There is a significant research-practice gap for understanding and influencing the role of exercise for patients with obesity and hypertension. This review provides recommendations for future research and consensus-based recommendations that promote exercise as a principle therapy for patients with obesity and hypertension.

Post-exercise Response of Arterial Parameters for Arterial Health Assessment Using a Microfluidic Tactile Sensor and Vibration-Model-Based Analysis: A Proof-of-Concept Study

OBJECTIVE

Arterial stiffness and endothelial function are two established surrogate markers of subclinical atherosclerosis and are quantified by three arterial parameters: elasticity, viscosity and radius of the arterial wall. Yet, the current methods for their assessment are unsuitable for routine use. Post-exercise response of the cardiovascular (CV) system serves as a more sensitive detection of subclinical arterial abnormalities that are not apparent at-rest. The objective of this study is to propose a novel method that can measure post-exercise response of arterial parameters and is also suitable for routine use.

APPROACH

A microfluidic tactile sensor with a location-insensitive configuration was used for arterial pulse signal measurements on six asymptomatic male subjects, offering measurement reliability, ease use by a layperson, and affordability. By treating the arterial pulse signal as a vibration signal of the arterial wall, vibration-model-based analysis of only one measured pulse signal with no calibration was conducted for simultaneous estimation of three arterial parameters. Exercise-intensity-normalized percent changes in arterial parameters were utilized to remove the influence of variation in exercise intensity on post-exercise response, and then their measured values were compared for difference in post-exercise response between the subjects.

MAIN RESULTS

One subject who was obese, on subject who had insomnia, and the oldest subject in the study demonstrated differences in post-exercise response at the radial artery (RA), as compared with the three subjects free of those three factors. Despite a lack of statistical significance, the observed difference at the RA between subjects was supported by (i) their consistency with the related findings in the literature, and (ii) their consistency with the measured values at the carotid artery (CA) and superficial temporal artery (STA) and the anatomical difference between the three arteries.

SIGNIFICANCE

The proposed method has the potential of offering an affordable and convenient diagnosis tool for routine arterial health assessment.

Acute Effects of Interrupting Prolonged Sitting With Intermittent Physical Activity on Blood Pressure in Preadolescent Children

PURPOSE

To compare the acute effects of intermittent physical activity (PA) across 4 different intensities on blood pressure.

METHODS

Thirty children (12 males and 18 females; aged 7-11 y; 33% overweight/obese; 53% nonwhite) completed 4 experimental conditions in random order: 8 hours sitting interrupted with 20, 2-minute low-, moderate-, high-intensity PA breaks, or sedentary screen-time breaks. PA intensity corresponded with 25%, 50%, and 75% of heart rate reserve. Blood pressure was measured during each condition in the morning (0800 h), noon (1200 h), and afternoon (1600 h).

RESULTS

There were no significant differences across conditions for systolic blood pressure (SBP; all Ps > .05). There was a significant effect of time with SBP decreasing throughout the day for all conditions (average morning SBP: 106 [1] mm Hg, average noon SBP: 101 [2] mm Hg, average afternoon SBP: 103 [1] mm Hg; P = .01). There were no significant effects of condition or time on diastolic blood pressure (all Ps > .05).

CONCLUSION

While sedentary behavior is known to be associated with hypertension in both adults and children, a single bout of prolonged sitting may be insufficient to produce hypertensive effects in otherwise healthy children. Future research should examine the appropriate dose of intermittent PA to accrue hypotensive responses in preadolescent children.

The Role of Adrenomedullin in Cardiovascular Response to Exercise - A Review

Adrenomedullin (ADM), the product of the vascular endothelial and smooth muscle cells, and cardiomyocytes, is considered to be a local factor controlling vascular tone, cardiac contractility and renal sodium excretion. The aim of this article was to review the existing data on the effect of different types of exercise on plasma ADM concentration in healthy men. The results of studies on the effect of dynamic exercise on the plasma ADM are contradictory. Some authors reported an increase in plasma ADM, while others showed a slight decrease or did not observe any changes. The inverse relationship between plasma ADM and mean blood pressure observed during maximal exercise support the concept that ADM might blunt the exercise-induced systemic blood pressure increase. Positive relationships between increases in plasma ADM and those in noradrenaline, atrial natriuretic peptide (ANP) or interleukin-6 observed during prolonged exercise suggest that the sympathetic nervous system and cytokine induction may be involved in ADM release. Increased secretion of ADM and ANP during this type of exercise may be a compensatory mechanism attenuating elevation of blood pressure and preventing deterioration of cardiac function. Studies performed during static exercise have showed an increase in plasma ADM only in older healthy men. Positive correlations between increases in plasma ADM and those in noradrenaline and endothelin-1 may indicate the interaction of these hormones in shaping the cardiovascular response to static exercise. Inverse relationships between exercise-induced changes in plasma ADM and those in cardiovascular indices may be at least partly associated with inotropic action of ADM on the heart. Interactions of ADM with vasoactive peptides, catecholamines and hemodynamic factors demonstrate the potential involvement of this peptide in the regulation of blood pressure and myocardial contractility during exercise.

The training and detraining effect of high-intensity interval training on post-exercise hypotension in young overweight/obese women

PURPOSE

Studies evaluating the response in blood pressure (BP) following high-intensity interval training (HIIT) are scant even though there has been extensive work done on the BP response following acute and chronic low- to moderate-intensity aerobic and resistance exercise in both hypertensive and normotensive individuals. The present study sought to investigate the training and detraining effects of short-term HIIT on the post-exercise hypotension (PEH) response in overweight/obese young women.

METHOD

Twenty young untrained women volunteered for the study. Participants performed six HIIT sessions on a treadmill within 2 weeks (week 1: 10 × 1 min and week 2: 15 × 1 min intervals at 90-95% HRmax, separated by 1 min active recovery at 70% HRmax each session) and detrained for 2 weeks. Post-exercise BP was measured for 1 h following the first and last HIIT sessions.

RESULTS

Participants were normotensive (SBP: 119.2 ± 5.60 mmHg; DBP: 78.8 ± 4.12 mmHg) and had a BMI greater than 25 kg m(-2). The magnitude of the systolic hypotensive response was slightly greater after the six sessions HIIT compared to pre-training (5.04 and 4.28 mmHg, respectively), and both would be considered clinically significant (>3 mmHg decrease). After 2 weeks, detraining the PEH response was not clinically significant (1.08 mmHg decrease). The magnitude of the DBP response was only clinically significant following post- and detraining (4.26 and 3.87 mmHg, respectively).

CONCLUSION

The findings suggest that six HIIT sessions is sufficient to affect clinically significant PEH responses in young, overweight/obese women; however, the training effects are lost within 2 weeks of detraining.

Relationship between post-exercise heart rate variability and skinfold thickness

This investigation aimed to determine if groupings based upon sum of skinfold thickness (SF) would reflect the differences in heart rate variability (HRV) measured for up to 30-minutes following maximal exercise, and to determine the extent in variation in post-exercise HRV that could be accounted for between the following independent variables: SF, body mass index (BMI) and maximal oxygen consumption (VO2max). SF and BMI measurements were performed on fifty-four men who completed maximal exercise testing to determine VO2max. HRV was evaluated for five-minutes before (Pre), at 0-5 minutes post- (Post1) and 25-30 minutes post-exercise (Post2), and analyzed by frequency domain [high frequency (HF) power, and HF to low frequency power ratio (LF:HF)). Two groups were formed based on being above or below the sample mean value of SF. HF and LF:HF were significantly higher and lower, respectively, at Pre and Post 2 in Group 1 compared to Group 2 (p < 0.05), which remained after controlling for VO2max and BMI. Furthermore, there was a significant trend toward baseline in post-exercise HRV in Group 1 (p < 0.05) but not in Group 2 (p > 0.05). In addition, SF was the only variable to significantly relate to the post-exercise HRV parameters (p < 0.05). The findings of this investigation suggest greater SF is related to a delayed return of HRV toward baseline from maximal exercise. The association between SF and HRV is independent of VO2max and BMI.