The cardiovascular system after exercise

Central blood pressure and peripheral augmentation index following acute submaximal arm versus leg exercise

BACKGROUND

Aerobic exercises like running and cycling may lower cardiovascular disease (CVD) risk through favorable effects on central blood pressure and vascular function. Arm ergometry is a popular exercise modality used in rehabilitation settings, but little is known regarding the central hemodynamic and vascular effects of this form of exercise.

PURPOSE

To compare the acute effects of leg versus arm exercise on central blood pressure and vascular function.

METHODS

Twenty-one participants (n = 11 female, Age 21 ± 3, BMI 24.5 ± 3.2 kg/m2) completed two visits to the Human Performance Laboratory. Central systolic blood pressure (cSBP), central diastolic blood pressure (cDBP), and peripheral augmentation index (pAIx) were measured using a brachial oscillometric blood pressure cuff with measures being taken before and after 20 min of acute moderate-intensity (submaximal) arm or leg cycling exercise.

RESULTS

There was a condition-by-time interaction for pAIx (p = 0.011). pAIx slightly increased following arm exercise but significantly decreased following leg exercise. There was a condition-by-time interaction for cDBP (p = 0.011). cDBP significantly decreased following arm exercise but increased immediately following leg exercise. There was no condition-by-time interaction for cSBP (p = 0.721). There were similar acute increases in cSBP immediately post-exercise for both conditions.

CONCLUSION

Arm exercise increased pAlx and decreased cDBP compared to leg exercise. As an increase in pAIx may increase left ventricular work and a reduction in cDBP may reduce coronary perfusion pressure, these findings suggest that a single bout of arm exercise may not have the same favorable acute effect on central hemodynamic load as a single bout of leg exercise.

Exercise Preconditioning Preserves Cardiac Function and Enhances Cardiac Recovery Following Dobutamine Stimulation in Doxorubicin-Treated Rat Hearts

ABSTRACT

Exercise preconditioning has been shown to protect against doxorubicin (DOX)-induced cardiac dysfunction when hearts are maintained under resting conditions. However, it is unclear whether this exercise-induced protective effect is maintained when the heart is challenged with the β 1 -adrenergic receptor agonist dobutamine (DOB), which mimics acute exercise stress. Fischer 344 rats were randomly assigned to sedentary (SED) or voluntary wheel running (WR) groups for 10 weeks. At week 11, rats were treated with either 15 mg/kg DOX or saline. Five days later, ex vivo cardiac function was assessed using an isolated working heart model at baseline, during the infusion of 7.5 μg·kg -1 ·min -1 DOB, and during recovery. DOB infusion significantly increased left ventricular developed pressure (LVDP), maximal (dP/dt max ) and minimal (dP/dt min ) rate of left ventricular pressure development, and heart rate in all groups ( P < 0.05). SED + DOX also showed a lower baseline and recovery LVDP than WR + DOX (83 ± 12 vs. 109 ± 6 mm Hg baseline, 76 ± 11 vs. 100 ± 10 mm Hg recovery, P < 0.05). WR + DOX showed higher dP/dt max and lower dP/dt min when compared with SED + DOX during DOB infusion (7311 ± 1481 vs. 5167 ± 1436 mm Hg/s and -4059 ± 1114 vs.-3158 ± 1176 mm Hg/s, respectively). SED + DOX dP/dt max was significantly lower during baseline and during recovery when compared with all other groups ( P < 0.05). These data suggest that exercise preconditioning preserved cardiac function after DOX exposure even when the heart is challenged with DOB, and it appeared to preserve the heart's ability to recover from this functional challenge.

The effect of electro-magnetic-energy-regulation therapy on subjective sleep among elite players in Norwegian women's football

The current study investigated if Bio-Electro-Magnetic-Energy-Regulation (BEMER) therapy is affecting subjective sleep among a sample of 21 elite female football players in a Norwegian top series club. Subjective sleep was measured each day over a period of 273 consecutive days by using a smartphone application, PM Reporter Pro, which scheduled push messages to remind the participants to report sleep every morning. The study was conducted as a quasi-experimental design, with a control period before the introduction of BEMER therapy that lasted for 3 months, followed by an intervention period where BEMER therapy was used that lasted for 5 months. The collected data from the players in the control period served as their control compared to the data collected from the players in the intervention period. Analyses of variance (ANOVA) with False Discovery Rate adjusted p-values show that subjective sleep duration and subjective sleep quality are significantly reduced on game nights, both in the control period and in the experiment period. The results also show that subjective sleep duration and subjective sleep quality significantly increase in the experiment period compared to the control period. The findings indicate that BEMER therapy might serve as a tool to improve sleep.

Blood pressure response during exercise testing in individuals with and without hypertension: The value of the recovery phase

BACKGROUND

Hypertension and exercise testing are essential for cardiovascular risk assessment. However, an exact description of blood pressure (BP) in patients with a hypertensive response during exercise (HRE), especially in the recovery phase is lacking. Herein, we aimed to analyse BP and heart rate during exercise testing and recovery in patients with an HRE.

METHODS

800 patients aged 17-90 with an HRE during a standardized bicycle ergometry test were recruited. The BP behaviour during exercise testing was correlated with clinical data. Furthermore, data were analysed according to the presence of pre-existent hypertension.

RESULTS

Of the 800 patients included in this study 497 (62%) were previously diagnosed with hypertension. Analysis of covariance showed a significantly faster systolic (β [95% CI] 8.0 [4.9-11.1]) and diastolic (2.4 [0.4-4.4]) BP recovery 3 min after maximal exercise in patients without hypertension in univariable models. These results remained robust in fully adjusted models taking into account age, sex, body mass index, cardiovascular disease, and antihypertensive treatment for systolic (5.3 [1.2-9.4]) and diastolic BP (4.5 [1.9-7.0]). Furthermore, patients with hypertension displayed higher systolic BP during maximal exercise in univariable (3.8 [0.1-7.5]) and fully adjusted (5.5 [1.1-10.0]) models. There was no difference in maximum diastolic BP between groups.

CONCLUSION

In this large cohort study, patients without hypertension showed a faster systolic and diastolic BP recovery and lower maximal systolic BP compared to patients with hypertension. Overall, this study provides new insights into cardiovascular health during recovery phase.

Impact of Concurrent Exercise Training on Cardiac Autonomic Modulation, Metabolic Profile, Body Composition, Cardiorespiratory Fitness, and Quality of Life in Type 2 Diabetes with Cardiac Autonomic Neuropathy: A Randomized Controlled Trial

Background: Type 2 diabetes mellitus (T2DM) often leads to cardiac autonomic neuropathy (CAN), a severe complication affecting cardiovascular health. Exercise training is a proven intervention for improving metabolic control and cardiovascular health in T2DM, but the effects of concurrent exercise training (CET), combining aerobic and resistance exercises, on CAN are not fully understood. Objective: This randomized controlled trial investigates the impact of a structured CET program on cardiac autonomic modulation, metabolic profile, body composition, cardiorespiratory fitness (CRF), and quality of life (QoL) in individuals with T2DM and CAN. Methods: A total of 96 participants, aged 35-70 years, with T2DM and CAN, were randomized into CET (n = 48) and control (n = 48) groups. The CET group engaged in combined aerobic and resistance training three times per week for 13 weeks, while the control group received standard care. Primary outcomes included heart rate variability (HRV) and heart rate recovery (HRR). Secondary outcomes were metabolic profile, body composition, CRF, and QoL, which were assessed using standardized protocols and validated questionnaires. The trial was registered with the Clinical Trials Registry-India (CTRI/2021/09/036711). Results: Significant improvements were noted in the CET group compared to controls. HRV metrics (SDNN, RMSSD, pNN50, TP, LF power, HF power, and LF/HF ratio) and HRR metrics (HRR30s, HRR1, HRR2, and HRR3) all showed significant enhancements (p < 0.01). The CET group also exhibited substantial reductions in fasting blood glucose, postprandial blood glucose, HbA1c, waist circumference, hip circumference, and percentage body fat (p < 0.01). Improvements were observed in lipid profile markers and CRF (VO2max) (p < 0.01). QoL scores improved significantly in the CET group as per the ADDQoL-19 (p < 0.01). Conclusions: CET significantly enhances cardiac autonomic modulation, metabolic profile, body composition, CRF, and QoL in individuals with T2DM and CAN. These findings support the integration of CET into standard T2DM management to improve clinical outcomes and QoL. Further research is needed to explore the long-term benefits and broader applicability of CET in diverse diabetic populations.

Cardiovascular response to brisk walking on different surfaces in an innovative senior playground: a randomized trial in older adults

Brisk walking is a simple exercise for older adults. We aimed to assess the cardiovascular response to a short bout of brisk walking on walking loops in an innovative senior playground in Thailand. Twenty older adults were randomly assigned to brisk walking on artificial turf (AT group, n = 10) or an uneven surface (US group, n = 10). We assessed cardiovascular parameters, average walking speed, and rate of perceived exertion. Blood pressure, heart rate, rate-pressure product, and rate perceived exertion were significantly increased, while the mean RR interval of heart rate variability was significantly decreased in both AT and US groups after exercise compared with pre-exercise (p < 0.05). A greater change in systolic blood pressure was observed in the US group than in the AT group (p < 0.05). These data indicated that brisk walking on AT and US increases cardiovascular response. Our findings provide information on planning exercise programs for older adults.

Impact of supra-maximal interval training vs. high-intensity interval training on cardiac auto-regulation response in physically active adults

PURPOSE

This study aimed to examine the impact of supra-maximal interval training (SMIT) and high-intensity interval training (HIIT) on cardiac auto-regulation response.

METHODS

Physically active young adults volunteered to participate in the study with a randomized cross-over counterbalanced design (N = 12). HIIT sessions consisted of 20 bouts of 10 s of exercise followed by 50 s of recovery, totaling 20 min at two different intensities; "all-out (SMIT)" vs. "115-130% Wmax (HIIT)". The cardiac auto-regulation included heart rate variability (HRV) and vascular function. HRV and vascular function were measured at baseline and five different time points after acute exercise.

RESULTS

The SMIT was higher in workload (31%), peak heart rate (28%), and rate of perceived exertion (40%) compared with HIIT (all p < 0.001). The R-R interval, NN50, and pNN50 measured until 60 min after acute exercise was higher in the HIIT compared with SMIT (all p < 0.05). The SMIT elicited a greater shift in ln LF/HF ratio immediately after acute exercise (3802%, p < 0.01) and induced a decrease in bilateral ba-PWV at the time point 5 min after acute exercise, persisting until 65 min after (p < 0.05). Yet, HIIT showed no change over time in the frequency domain of HRV and blood vascular tone after cessation of acute exercise.

CONCLUSION

Our findings confirmed that SMIT is a more potent modulator of the autonomic nervous system compared with HIIT. Further study is needed to monitor through complete recovery to baseline, to understand acute cardiac auto-regulation response after cessation of various exercise intensities identical interval training protocol.

Eccentric muscle-damaging exercise in the heat lowers cellular stress prior to and immediately following future exertional heat exposure

Muscle-damaging exercise (e.g., downhill running [DHR]) or heat exposure bouts potentially reduce physiological and/or cellular stress during future exertional heat exposure; however, the true extent of their combined preconditioning effects is unknown. Therefore, this study investigated the effect of muscle-damaging exercise in the heat on reducing physiological and cellular stress during future exertional heat exposure. Ten healthy males (mean ± Standard Definition; age, 23 ± 3 years; body mass, 78.7 ± 11.5 kg; height, 176.9 ± 4.7 cm) completed this study. Participants were randomly assigned into two preconditioning groups: (a) DHR in the heat (ambient temperature [Tamb], 35 °C; relative humidity [RH], 40%) and (b) DHR in thermoneutral (Tamb, 20 °C; RH, 20%). Seven days following DHR, participants performed a 45-min flat run in the heat (FlatHEAT [Tamb, 35 °C; RH, 40%]). During exercise, heart rate and rectal temperature (Trec) were recorded at baseline and every 5-min. Peripheral blood mononuclear cells were isolated to assess heat shock protein 72 (Hsp72) concentration between conditions at baseline, immediately post-DHR, and immediately pre-FlatHEAT and post-FlatHEAT. Mean Trec during FlatHEAT between hot (38.23 ± 0.38 °C) and thermoneutral DHR (38.26 ± 0.38 °C) was not significantly different (P = 0.68), with no mean heart rate differences during FlatHEAT between hot (172 ± 15 beats min-1) and thermoneutral conditions (174 ± 8 beats min-1; P = 0.58). Hsp72 concentration change from baseline to immediately pre-FlatHEAT was significantly lower in hot (-51.4%) compared to thermoneutral (+24.2%; P = 0.025) DHR, with Hsp72 change from baseline to immediately post-FlatHEAT also lower in hot (-52.6%) compared to thermoneutral conditions (+26.3%; P = 0.047). A bout of muscle-damaging exercise in the heat reduces cellular stress levels prior to and immediately following future exertional heat exposure.

Investigation of left atrial mechanical function and left ventricular systolic and diastolic parameters in athletes performing resistance exercise and combined exercise

Some individuals who go to fitness centers for various purposes perform resistance exercise (RE) alone, while others engage in combined exercise (CE) by including cardio exercises along with RE. Studying the effects of these two different training methods on left ventricular (LV) systolic and diastolic parameters and left atrial mechanical function is an important step toward understanding the effects of different types of exercise on cardiac function. This knowledge has significant implications for public health, as it can inform the development of targeted and effective exercise programs that prioritize cardiovascular health and reduce the risk of adverse outcomes. Therefore, the primary aim of this study is to comprehensively investigate the LV systolic and diastolic parameters of athletes who engage in RE and CE using ECHO, to contribute to the growing body of literature on the cardiovascular effects of different types of exercise. Forty-two amateur athletes aged between 17 and 52 were included in our study. The participants consisted of the RE (n = 26) group who did only resistance exercise during the weekly exercise period, and the CE group (n = 16) who also did cardio exercise with resistance exercises. After determining sports age (year), weekly exercise frequency (day), and training volume (min) in addition to demographic information of RE and CE groups, left ventricular systolic and diastolic parameters and left atrial functions were determined by ECHO. Findings from our study revealed that parameters including the left ventricular end-diastolic diameter (LVEDD) (p = .008), left ventricular end-diastolic volume (LVEDV) (p = .020), stroke volume index (SV-I) (p = .048), conduit volume (CV-I) (p = .001), and aortic strain (AS) (p = .017) were notably higher in the RE group compared to the CE group. Also left atrial active emptying volüme (LAAEV) of CE was higher than the RE group (p = .031). In conclusion, the cardiac parameters of the RE group showed more athlete's heart characteristics than the CE group. These results may help to optimize the cardiovascular benefits of exercise routines while minimizing the potential risks associated with improper training.

Central and peripheral mechanisms underlying postexercise hypotension: a scoping review

Blood pressure (BP) reduction occurs after a single bout of exercise, referred to as postexercise hypotension (PEH). The clinical importance of PEH has been advocated owing to its potential contribution to chronic BP lowering, and as a predictor of responders to exercise training as an antihypertensive therapy. However, the mechanisms underlying PEH have not been well defined. This study undertook a scoping review of research on PEH mechanisms, as disclosed in literature reviews. We searched the PubMed, Web of Science, Scopus, Cumulated Index to Nursing and Allied Health Literature (CINAHL), Cochrane Library, and Sport Discus databases until January 2023 to locate 21 reviews - 13 narrative, four systematic with 102 primary trials, and four meta-analyses with 75 primary trials involving 1566 participants. We classified PEH mechanisms according to major physiological systems, as central (autonomic nervous system, baroreflex, cardiac) or peripheral (vascular, hemodynamic, humoral, and renal). In general, PEH has been related to changes in autonomic control leading to reduced cardiac output and/or sustained vasodilation. However, the role of autonomic control in eliciting PEH has been challenged in favor of local vasodilator factors. The contribution of secondary physiological outcomes to changes in cardiac output and/or vascular resistance during PEH remains unclear, especially by exercise modality and population (normal vs. elevated BP, young vs. older adults). Further research adopting integrated approaches to investigate the potential mechanisms of PEH is warranted, particularly when the magnitude and duration of BP reductions are clinically relevant. (PROSPERO CRD42021256569).

Effects of intermittent pneumatic compression on the recovery of cardiovascular parameters after repeated sprint exercise

PURPOSE

Intermittent pneumatic compression (IPC) applies gradual pressure to facilitate lymph and blood flow movement to reduce exercise-induced tissue fluid accumulation and plasma volume loss. This study aimed to evaluate the cardiovascular system response during the recovery with IPC compared with passive recovery (Sham).

METHODS

Sixteen volunteers (7 females and 9 males) executed a cycling-based exhausting sprint interval exercise (8 × 20 s all out), followed by a 30-min IPC or Sham condition. Participants performed two trials in a randomised, counterbalanced, and crossover design. Several cardiovascular parameters (blood pressure, heart function, and peripheral vascular resistance) were recorded at baseline (5'), through the recovery protocol (30'), and afterwards (5').

RESULTS

The use of IPC during the recovery phase led to a faster recovery, stated in relative values to pre-exercise, in mean blood pressure (102.5 ± 19.3% vs. 92.7 ± 12.5%; P < 0.001), and cardiac output (139.8 ± 30.0% vs. 146.2 ± 40.2%; P < 0.05) in comparison to Sham condition. Furthermore, during the IPC-based recovery, there was a slower recovery in cardiac pressure change over time (92.5 ± 25.8% vs. 100.5 ± 48.9%; P < 0.05), and a faster return to pre-exercise values in the peripheral vascular resistance (75.2 ± 25.5% vs. 64.8 ± 17.4%; P < 0.001) compared to Sham.

CONCLUSION

The application of IPC after high-intensity exercise promotes the recovery of the cardiovascular system, reducing cardiovascular strain. Future investigations should consider the effects on the sympathetic-parasympathetic balance, such as heart rate variability, to assess further bonds between the use of IPC and autonomous control.

Reducing thrombotic risks in video gamers: investigating the benefits of walking and compression sleeves on blood hemodynamics

With the growing popularity of video gaming, deep vein thromboses are increasingly being reported in gamers. This study aimed to compare the effects of lower leg graduated compression sleeves and a 6-min walking break during prolonged gaming on blood flow and hemodynamics in competitive sport players to help mitigate this risk. Ten healthy gamers (19.6 ± 1.2 yr old; 9 men) consented to participate in this mixed-model crossover design study that consisted of three visits. In visit 1, participants engaged in continuous 2-h video game play wearing no compression (continuous). Visits 2 and 3 involved 2-h play wearing compression sleeves (compression) and 2-h game play interrupted at 1 h by a 6-min walk (walk). Doppler ultrasound measurements of the left popliteal artery were taken at 30, 60, 90, and 120 min, to record vessel diameter, blood flow velocity, and blood flow volume. Participants completed a survey to assess their perception of each approach. There was a significant interaction between conditions for blood flow and blood velocity (P = 0.01, P < 0.001). Post hoc analysis demonstrated a greater decrease in blood flow and blood velocity in the continuous group compared with the walk group at the 90-min mark (P = 0.04, P = 0.01). No differences were found between the compression and walk groups or between the continuous and compression groups (P = 0.42, P = 0.69). No interactions were observed in diameter, mean arterial pressure, or heart rate. This study suggests that incorporating a 6-min walk every 60 min during prolonged gaming is advisable to counteract the negative effects on blood flow hemodynamics.NEW & NOTEWORTHY A 6-min light-intensity walking break during gaming can effectively combat the adverse effects of prolonged sitting, surpassing compression garments. Prolonged sitting reduces blood flow velocity, potentially leading to deep vein thrombosis (DVT). Compression sleeves help, with superior results after a 6-min walk at 60 min. Although compression stockings offer moderate improvements, a 6-min active break proves more effective. These findings offer promising interventions for gamers' health, initiating guidelines to mitigate DVT risk during gaming.

Postexercise cardiovascular hemodynamics assessment before and after a 30-minute standing still recovery

BACKGROUND

Although postexercise syncope usually occurs shortly after physical exercise conclusion, athletes commonly reveal symptoms of postexercise hypotension several tens of minutes after exercise completion. Currently, no studies have investigated central hemodynamic regulation during posture changes occurring several tens of minutes after exercise compared to immediately after cessation.

METHODS

This study examined changes in mean arterial pressure (MAP), heart rate (HR), systemic vascular conductance (SVC), cardiac output, and stroke volume during two sets of tilt tests performed before vs. after a 30-minute standing still recovery, respectively. Tilt tests were performed after a short-lasting supramaximal test (WNG) and long-lasting maximal incremental test (INC) in 12 young endurance-trained individuals.

RESULTS

The key findings were that, regardless of the exercise type, the 30-minute recovery augmented (P<0.01) the increase in HR and the drop in SVC during the transition from supine to upright, although the MAP drop was similar (P=0.99) after vs. before recovery. INC led to greater increases (P<0.01) in HR and drops (P<0.01) in SVC compared to WNG during postural transitions both before and after the recovery.

CONCLUSIONS

These findings suggest that, in a population that tolerates postexercise hypotension, MAP neural control is more challenged after a 30-minute standing still recovery than before, as evidenced by an augmented vasodilation capacity along with an increased HR buffering response during posture changes. Moreover, our data suggest that effective MAP control is resulting from an equally effective HR buffering response on MAP. Therefore, exercises that induce greater systemic vasodilation lead to greater HR buffering responses.

Effectiveness of different recovery postures during high-intensity interval training

BACKGROUND

High-intensity interval training (HIIT) has become a very popular mode of exercise practiced by the elite as well as recreationally active adults. The aim of this study was to evaluate the effects of four recovery postures that are typically used by exercisers on recovery rate and performance in subsequent bouts of HIIT.

METHODS

Sixteen young, healthy adults performed four HIIT trials with randomized recovery postures. Each trial consisted of four sets of modified Wingate anaerobic power tests (20-sec duration) on a cycle ergometer (Monark 894E, Vansbro, Sweden) separated by four-minute recovery between each exercise set. Participants adopted one of four recovery postures immediately following each set: standing still with hands on the back of the head (head), standing still with hands resting on knees (knees), slow walking with hands on hips (walking), or supine rest (supine). Differences were assessed by a two-way (posture × set) repeated measures analysis of variance.

RESULTS

Peak and mean anaerobic power progressively declined within each set (P<0.05), with no differences between postures. Fatigue rate was significantly slower during supine (59±12%) than knees (63±13%). Heart rate recovery was faster (P<0.001) during supine than the other three standing postures. Pulmonary ventilation was not significantly different between postures. Blood lactate concentrations measured after HIIT were not significantly different between postures.

CONCLUSIONS

Supine posture appears to be more advantageous in facilitating recovery when compared to the three standing postures. None of the recovery postures examined was responsible for better performance in subsequent bouts of HIIT.

The Influence of Menstrual-Cycle Phase on Measures of Recovery Status in Endurance Athletes: The Female Endurance Athlete Project

PURPOSE

To investigate the influence of menstrual-cycle (MC) phase on measures of recovery status, that is, resting heart rate, perceived sleep quality, and physical and mental readiness to train, among female endurance athletes.

METHODS

Daily data were recorded during 1 to 4 MCs (ie, duration ≥21 and ≤35 d, ovulatory, luteal phase ≥10 d) of 41 trained-to-elite-level female endurance athletes (mean [SD]: age 27 [8] y, weekly training: 9 [3] h). Resting heart rate was assessed daily using a standardized protocol, while perceived sleep quality and physical and mental readiness to train were assessed using a visual analog scale (1-10). Four MC phases (early follicular phase [EFP], late follicular phase, ovulatory phase, and midluteal phase [MLP]) were determined using the calendar-based counting method and urinary ovulation-prediction test. Data were analyzed using linear mixed-effects models.

RESULTS

Resting heart rate was significantly higher in MLP (1.7 beats·min-1, P = .006) compared with EFP without significant differences between the other MC phases. Perceived sleep quality was impaired in MLP compared with late follicular phase (-0.3, P = .035). Physical readiness to train was lower both in ovulatory phase (-0.6, P = .015) and MLP (-0.5, P = .026) compared with EFP. Mental readiness to train did not show any significant differences between MC phases (P > .05).

CONCLUSIONS

Although significant, the findings had negligible to small effect sizes, indicating that MC phase is likely not the main determinant of changes in measures of recovery status but, rather, one of the many possible stressors.

Prone restraint death: Possible role of the Valsalva maneuver

There is an on-going debate about the safety of prone restraint and the exact role of the prone position in physical restraint death. Cardiac arrest in prone restraint death is essentially the end-result of a violent physical altercation wherein a combative individual suddenly loses consciousness while trying to counteract an opposing force. The direct correlations of increased static weight force with decreased inferior vena cava diameter, decreased cardiac output, and decreased stroke volume in prone restraint studies suggest that decreased venous return and decreased cardiac output could have a significant role to play in prone restraint death. Although the degree of changes observed in those studies might not be sufficient to cause cardiac arrest, they could predispose people who instinctively try to free themselves of the restraints to severe complications. The Valsalva maneuver, or forceful expiration against a closed airway, is frequently performed spontaneously in daily activities involving straining and resistance exercise, but has never been considered in restraint death. Pre-existing diminished venous return could increase the risk of major complications in individuals performing the Valsalva maneuver. A substantial decrease in venous return and cardiac output could increase the risk of cerebral hypoperfusion, loss of consciousness, hypoventilation, and sudden death. By increasing the risk of increased intra-abdominal pressure and its negative effect on venous return, high body mass index may be a significant risk factor in prone restraint death. The Valsalva maneuver may have different roles in prone restraint cardiac arrest and might be overlooked in prone restraint death.

Evaluation of electrocardiographic parameters in amputee football players

OBJECTIVE

The present study aimed to compare electrocardiographic (ECG) parameters of amputee football players (AF) with football players without disability (FP) and sedentary individuals without disability (SI).

METHODS

A total of 32 participants (AF = 9, FP = 11, SI = 12) were included in the study. ECG parameters including P-wave amplitude, P-wave duration, PR interval, QRS duration, RR interval, QT interval, corrected-QT interval (QTc), ST segment duration, Tp-e duration, Tp-e/QT and Tp-e/QTc ratios were assessed in all the study participants by using a 12-lead ECG device. OneWay ANOVA Test was used for statistical analysis.

RESULTS

Of all ECG parameters, P-wave amplitude and QTc were significantly higher in the AF group in comparison to FP and SI groups. QRS duration was found to be lower in the AF group when compared to FP and SI groups. Myocardial repolarization parameters including Tp-e duration, Tp-e/QT and Tp-e/QTc ratios were similar between groups, as were other parameters such as P-wave duration, PR interval, RR interval, QRS duration and QT interval.

CONCLUSION

It was found that some ECG parameters of amputee football players differ from those with non-disabled players and non-disabled sedentary individuals. These different parameters were within normal limits.

Exercise and cardiovascular health: A state-of-the-art review

Cardiovascular (CV) disease (CVD) is the leading cause of global morbidity and mortality, and low levels of physical activity (PA) is a leading independent predictor of poor CV health and associated with an increased prevalence of risk factors that predispose to CVD development. In this review, we evaluate the benefits of exercise on CV health. We discuss the CV adaptations to exercise, focusing on the physiological changes in the heart and vasculature. We review the impact and benefits of exercise on specific CV prevention, including type II diabetes, hypertension, hyperlipidemia, coronary artery disease, and heart failure, in addition to CVD-related and all-cause mortality. Lastly, we evaluate the current PA guidelines and various modes of exercise, assessing the current literature for the effective regimens of PA that improve CVD outcomes.

Association of Gene Variants with Seasonal Variation in Muscle Strength and Aerobic Capacity in Elite Skiers

Background: The training of elite skiers follows a systematic seasonal periodization with a preparation period, when anaerobic muscle strength, aerobic capacity, and cardio-metabolic recovery are specifically conditioned to provide extra capacity for developing ski-specific physical fitness in the subsequent competition period. We hypothesized that periodization-induced alterations in muscle and metabolic performance demonstrate important variability, which in part is explained by gene-associated factors in association with sex and age. Methods: A total of 34 elite skiers (20.4 ± 3.1 years, 19 women, 15 men) underwent exhaustive cardiopulmonary exercise and isokinetic strength testing before and after the preparation and subsequent competition periods of the World Cup skiing seasons 2015-2018. Biometric data were recorded, and frequent polymorphisms in five fitness genes, ACE-I/D (rs1799752), TNC (rs2104772), ACTN3 (rs1815739), and PTK2 (rs7460, rs7843014), were determined with specific PCR reactions on collected DNA. Relative percentage changes of cardio-pulmonary and skeletal muscle metabolism and performance over the two seasonal periods were calculated for 160 data points and subjected to analysis of variance (ANOVA) to identify hypothesized and novel associations between performance alterations and the five respective genotypes and determine the influence of age × sex. A threshold of 0.1 for the effect size (h2) was deemed appropriate to identify relevant associations and motivate a post hoc test to localize effects. Results: The preparation and competition periods produced antidromic functional changes, the extent of which varied with increasing importance for anaerobic strength, aerobic performance, cardio-metabolic efficiency, and cardio-metabolic/muscle recovery. Only peak RER (-14%), but not anaerobic strength and peak aerobic performance, and parameters characterizing cardio-metabolic efficiency, differed between the first and last studied skiing seasons because improvements over the preparation period were mostly lost over the competition period. A number of functional parameters demonstrated associations of variability in periodic changes with a given genotype, and this was considerably influenced by athlete "age", but not "sex". This concerned age-dependent associations between periodic changes in muscle-related parameters, such as anaerobic strength for low and high angular velocities of extension and flexion and blood lactate concentration, with rs1799752 and rs2104772, whose gene products relate to sarcopenia. By contrast, the variance in period-dependent changes in body mass and peak VO2 with rs1799752 and rs2104772, respectively, was independent of age. Likely, the variance in periodic changes in the reliance of aerobic performance on lactate, oxygen uptake, and heart rate was associated with rs1815739 independent of age. These associations manifested at the post hoc level in genotype-associated differences in critical performance parameters. ACTN3 T-allele carriers demonstrated, compared to non-carriers, largely different periodic changes in the muscle-associated parameters of aerobic metabolism during exhaustive exercise, including blood lactate and respiration exchange ratio. The homozygous T-allele carriers of rs2104772 demonstrated the largest changes in extension strength at low angular velocity during the preparation period. Conclusions: Physiological characteristics of performance in skiing athletes undergo training period-dependent seasonal alterations the extent of which is largest for muscle metabolism-related parameters. Genotype associations for the variability in changes of aerobic metabolism-associated power output during exhaustive exercise and anaerobic peak power over the preparation and competition period motivate personalized training regimes. This may help to predict and maximize the benefit of physical conditioning of elite skiers based on chronological characteristics and the polymorphisms of the ACTN3, ACE, and TNC genes investigated here.

A comparison of low and high dose of moderate intensity aerobic exercise on heart rate recovery of the sedentary adults: a pragmatic randomized controlled trial

BACKGROUND

Heart rate recovery (HRR) has been used as a prognostication marker of health. A slower drop in HRR is linked to a higher risk of cardiovascular diseases and all-cause mortality. Since aerobic exercise has been shown to have favorable effects on HRR, we aimed to compare the effects of two different aerobic exercise doses on HRR among a sedentary adult population.

METHODS

A pragmatic randomised controlled trial was conducted on 29 healthy sedentary adults (seven males and 22 females) in a 12-week exercise program. They were randomly assigned to group A (75 min/week, N.=15) or group B (150 min/week, N.=14) of moderate intensity aerobic exercise groups. HRR at 1-minute (HRR1), HRR at 2-minute (HRR2), and peak oxygen uptake (VO<inf>2peak</inf>) were measured pre- and post-intervention.

RESULTS

The improvements of HRR1 and HRR2 were seen in both groups but was only significant (P<0.05) for group A with HRR1, -4.07 bpm (post 24.47±6.42 - pre 20.40±5.51, P=0.018) and HHR2, -3.93 bpm (post 43.40±13.61 - pre 39.47±10.68, P=0.046). Group B showed increment of HRR1, -1.14 bpm (post 21.14±5.35 - pre 20.00±6.30, P=0.286) and HRR2, -2.5 bpm, (post 39.36±8.01 - pre 36.86±9.57, P=0.221). Improvement of the VO<inf>2peak</inf> was only significant in group B with an increment of 1.52±2.61 (P=0.049).

CONCLUSIONS

In conclusion, our study suggests that improvements in heart rate recovery (HRR1 and HRR2) among sedentary healthy adults can be achieved by engaging in moderate intensity exercise at a dose lower than the current recommended guidelines. The lower dose seems to be more attainable and may encourage exercise compliance. Future studies should further explore the effects of different exercise volumes on HRR in a larger sample size and also by controlling for BMI or gender.

Effect of Three-Month Weight Training Program on Resting Heart Rate and Blood Pressure in Healthy Young Adult Males

Background A planned and structured physical activity is the cornerstone of improving and sustaining body fitness. The underlying reason for exercise is personal interest, maintaining good health, or improving endurance for sports. Furthermore, exercise may be either isotonic or isometric. In weight training, different types of weight are being used and are lifted against gravity, and this type of exercise is of isotonic type. Objective The objective of this study was to observe the changes in heart rate (HR) and blood pressure (BP) after a three-month weight training intervention in healthy young adult males and to compare them with age-matched healthy control. Materials and methods We initially recruited a total of 25 healthy male volunteers for the study and 25 age-matched participants in the control group. Research participants were screened for any existing diseases and suitability for participation by the Physical Activity Readiness Questionnaire. We lost one participant from the study group and three participants from the control group in the follow-up. A structured weight training program (five days a week for three months) was applied for the study group with direct instruction and supervision in a controlled environment. A single expert clinician measured baseline and post-program (after three months) HR and BP (measured after 15 minutes, 30 minutes, and 24 hours of rest after exercise) to reduce any possible inter-observer variation. For comparing the pre-exercise and post-exercise parameters, we considered the post-exercise measurement, which was done after 24 hours of exercise. Mann-Whitney U test, Wilcoxon signed-rank test, and Friedman test compared the parameters. Result A total of 24 males with a median age of 19 years (Q1-Q3: 18-20) participated as the study group and 22 males with the same median age were the control group. At the end of the three-month weight training exercise program, there was no significant change in the HR (median 82 versus 81 bpm, p = 0.27) in the study group. The systolic BP was increased (median 116 versus 126 mmHg, p <0.0001) after three months of the weight training program. In addition, pulse pressure and mean arterial BP was also increased. However, diastolic (median 76 versus 80 mmHg, p = 0.11) BP was not significantly increased. There was no change in HR, systolic and diastolic BP in the control group. Conclusion A structured weight training program (used in this study) for three months may sustain an increase in systolic BP at rest in young adult males while diastolic BP remains the same. The HR remains unchanged before and after the exercise program. Hence, those enrolling in such an exercise program should be monitored frequently for changes in BP over time for any timely intervention appropriate for the candidate. However, being a small-scale study, the result of this study would be validated by further observing the underlying causes of the increment of systolic blood pressure.

Urinary Metabolomics in Young Soccer Players after Winter Training Season

During the off-season, soccer players in Korea attend the winter training season (WTS) to build running stamina for the next season. For young soccer players, proper recovery time is needed to prevent injury or muscle damage. In this study, urinary metabolites in young players after 1, 5, and 10 days of the WTS were analyzed using nuclear magnetic resonance spectroscopy (NMR) combined with multivariate analysis to suggest appropriate recovery times for improving their soccer skills. After NMR analysis of the urine samples obtained from young players, 79 metabolites were identified, and each group (1, 5, or 10 days after WTS) was separated from the before the WTS group in the target profiling analysis using partial least squares-discriminant analysis (PLS-DA). Of these, 15 metabolites, including 1-methylnicotinamide, 3-indoxylsulfate, galactarate, glutamate, glycerol, histamine, methylmalonate, maltose, N-phenylacetylglycine, trimethylamine, urea, 2-hydroxybutyrate, adenine, alanine, and lactate, were significantly different than those from before the WTS and were mainly involved in the urea, purine nucleotide, and glucose-alanine cycles. In this study, most selected metabolites increased 1 day after the WTS and then returned to normal levels. However, 4 metabolites, adenine, 2-hydroxybutyrate, alanine, and lactate, increased during the 5 days of recovery time following the WTS. Based on excess ammonia, adenine, and lactate levels in the urine, at least 5 days of recovery time can be considered appropriate.

Effects of exercise modalities on decreased blood pressure in patients with hypertension

This study aimed to evaluate the acute effects of aerobic and resistance exercises on blood pressure and endothelial blood markers. We also correlated post-exercise blood pressure response with baseline cardiovascular parameters in middle-aged patients with hypertension. This cross-sectional study randomized 54 volunteers into the aerobic exercise group (AG, n = 27; 45.6 ± 7.7 years) or dynamic resistance exercise group (RG, n = 27; 45.8 ± 8.4 years). Blood marker evaluation, cardiopulmonary exercise tests, resting blood pressure monitoring, ambulatory blood pressure monitoring (ABPM), flow-mediated dilatation monitoring, and body composition evaluation were carried out. Exercise sessions were performed to evaluate post-exercise hypotension (PEH) and endothelial marker responses, in addition to post-exercise ABPM (ABPMex). This study is an arm of the study which was approved by the local ethics committee (No. 69373217.3.0000.5347) in accordance with the Helsinki Declaration and was registered at ClinicalTrials.gov (NCT03282942). The AG performed walking/running at 60% of the reserve heart rate, while the RG performed 10 exercises with two sets of 15-20 repetitions. The mean 24 h ABPM and ABPMex values showed no significant statistical differences. Systolic and diastolic blood pressure hypotension after aerobic and dynamic resistance were -10.59 ± 5.24/-6.15 ± 6.41 mmHg and -5.56 ± 7.61/-6.20 ± 8.25 mmHg, respectively. For an up-to-7 h assessment of resting pressure, there was a positive effect in the aerobic group. The concentrations of nitrites/nitrates (NOx) and endothelin-1 (ET-1) did not change during hypotension. Moreover, PEH and ABPMex were significantly correlated with baseline health variables. Thus, when middle-aged patients with hypertension perform aerobic or resistance exercise, the NOx/ET-1 pathway does not provide the best explanation for PEH. Finally, we found associations between baseline cardiovascular variables and endothelial vasoconstrictors with PEH.

Acute Floatation-REST Improves Perceived Recovery After a High-Intensity Resistance Exercise Stress in Trained Men

PURPOSE

The aim of the present investigation was to determine whether a 1-h floatation-restricted environmental stimulation therapy (floatation-REST) session could augment recovery from high-intensity resistance exercise (6 × 10 back squats, 2-min rest) known to induce significant metabolic, adrenergic, and mechanical stress.

METHODS

Eleven healthy resistance-trained males (age, 22.5 ± 2.3 yr; height, 176.4 ± 6.0 cm; weight, 85.7 ± 6.2 kg; back squat one-repetition maximum, 153.1 ± 20.1 kg; strength-to-weight ratio, 1.8 ± 0.2) completed the within-subject, crossover controlled study design. Participants completed two exercise testing blocks separated by a 2-wk washout. In one block, the high-intensity resistance exercise protocol was followed by a 1-h floatation-REST session, whereas recovery in the alternate block consisted of a passive sensory-stimulating control. Markers of metabolic stress, neuroendocrine signaling, structural damage, inflammation, and perceptions of soreness, mood state, and fatigue were assessed over a 48-h recovery window.

RESULTS

Floatation-REST significantly attenuated muscle soreness across recovery ( P = 0.035) with greatest treatment difference immediately after the intervention ( P = 0.002, effect size (ES) = 1.3). Significant differences in norepinephrine ( P = 0.028, ES = 0.81) and testosterone ( P = 0.028, ES = 0.81) immediately after treatment revealed the modification of neuroendocrine signaling pathways, which were accompanied by greater improvements in mood disturbance ( P = 0.029, ES = 0.81) and fatigue ( P = 0.001, ES = 1.04).

CONCLUSIONS

Because no adverse effects and significant and meaningful benefits were observed, floatation-REST may prove a valuable intervention for managing soreness and enhancing performance readiness after exercise.

High-intensity functional exercise does not cause persistent elevations in augmentation index in young men and women

Elevations in central augmentation index (AIx) are predictive of cardiovascular disease. Our objective was to examine AIx immediately and 24-hrs following an acute bout of high-intensity functional training (HIFT) in apparently healthy young adults. A second aim compared the exercise induced AIx recovery response between men and women. Thirty-two recreationally active younger adults (n=16 men) were tested. Baseline central hemodynamic measures were assessed, followed by a single bout of bodyweight HIFT. The HIFT included four rounds of burpees, jump squats, split squats, and walking lunges. Assessments were repeated 5-, 10-, 15- and 24-hrs post exercise. AIx was normalized to a heart rate of 75 bpm (AIx75). There was a significant main effect of time on AIx75 across all groups (p<0.001) with AIx75 increasing at all acute timepoints compared with baseline and returning to resting values 24-hrs post-exercise. When examining sex differences after covarying for height and body fat percentage, we found no time*sex interaction (p=0.62), or main effect for sex (p=0.41), but the significant main effect of time remained (p<0.001). The AIx75 response to HIFT follows a similar recovery pattern as previously studied modes of exercise with no residual effects 24 hrs later and no differences between men and women indicating no persistent cardiovascular strain in younger adults participating in this mode of exercise.

High intensity exercise and passive hot water immersion cause similar post intervention changes in peripheral and cerebral shear

Passive hot water immersion (PHWI) provides a peripheral vasculature shear stimulus comparable to low intensity exercise within the active skeletal muscle, whereas moderate and high intensity exercise elicit substantially greater shear rates in the peripheral vasculature, likely conferring greater vascular benefits. Few studies have compared post intervention shear rates in the peripheral and cerebral vasculature following high intensity exercise and PHWI, especially considering that the post intervention recovery period represents a key window in which adaptation occurs. Therefore, we aimed to compare shear rates in the internal carotid artery (ICA), vertebral artery (VA) and common femoral artery (CFA) between high intensity exercise and PHWI for up to 80 minutes post intervention. Fifteen healthy (27 ± 4 years), moderately trained individuals underwent three-time matched interventions in a randomised order which included 30 minutes of whole-body immersion in a 42°C hot bath, 30 minutes of treadmill running and 5x4 minute high intensity intervals (HIIE). There were no differences in ICA (P= 0.4643) and VA (P=0.1940) shear rates between PHWI and exercise (both continuous and HIIE) post intervention. All three interventions elicited comparable increases in CFA shear rate post intervention (P=0.0671), however, CFA shear rate was slightly higher 40 minutes post threshold running (P=0.0464) and, slightly higher, although not statically for HIIE (P=0.0565) compared with PHWI. Our results suggest that time and core temperature matched high intensity exercise and PHWI elicit limited changes in cerebral shear and comparable increases in peripheral vasculature shear rates when measured for up to 80 minutes post intervention.

Time course recovery of cerebral blood velocity metrics post aerobic exercise: A systematic review

Currently, the standard approach for restricting exercise prior to cerebrovascular data collection varies widely between 6-24 hours. This universally employed practice is a conservative approach to safeguard physiological alterations that could potentially confound one's study design. Therefore, the purpose of this systematic review was to amalgamate the literature that examines the extent and duration cerebrovascular function is impacted following aerobic exercise measured via transcranial Doppler ultrasound. Further, an exploratory aim was to scrutinize and discuss common biases/limitations in the previous studies to help guide future investigations. Search strategies were developed and imported into PubMed, SPORTDiscus, and Medline databases. A total of 595 records were screened and 35 articles met the inclusion criteria in this review, which included assessments of basic cerebrovascular metrics (n=35), dynamic cerebral autoregulation (dCA; n=9), neurovascular coupling (NVC; n=2); and/or cerebrovascular reactivity (CVR-CO₂; n=1) following acute bouts of aerobic exercise. Across all studies, it was found NVC was impacted for 1-hour, basic cerebrovascular parameters and CVR-CO₂ parameters 2-hours, and dCA metrics 6-hours post-exercise. Therefore, future studies can provide participants with these evidence-based time restrictions, regarding the minimum time to abstain from exercise prior to data collection. However, it should be noted, other physiological mechanisms could still be altered (e.g., metabolic, hormonal, and/or autonomic influences), despite cerebrovascular function returning to baseline levels. Thus, future investigations should seek to control for as many physiological influences when employing cerebrovascular assessments, immediately following these time restraints. The main limitations/biases were lack of female participants, cardiorespiratory fitness, and consideration for vessel diameter.

Age Differences in Recovery Rate Following an Aerobic-Based Exercise Protocol Inducing Muscle Damage Among Amateur, Male Athletes

Purpose: Compare recovery rates between active young (Y) and middle-aged (MA) males up to 48H post aerobically based, exercise-induced muscle damage (EIMD) protocol. A secondary aim was to explore the relationships between changes in indices associated with EIMD and recovery throughout this timeframe.

Methods: Twenty-eight Y (n = 14, 26.1 ± 2.9y, 74.5 ± 9.3 kg) and MA (n = 14, 43.6 ± 4.1y, 77.3 ± 12.9 kg) physically active males, completed a 60-min downhill running (DHR) on a treadmill at −10% incline and at 65% of maximal heart rate (HR). Biochemical, biomechanical, psychological, force production and muscle integrity (using MRI diffusion tensor imaging) markers were measured at baseline, immediately-post, and up to 48H post DHR.

Results: During the DHR, HR was lower (p < 0.05) in MA compared to Y, but running pace and distance covered were comparable between groups. No statistical or meaningful differences were observed between groups for any of the outcomes. Yet, Significant (p < 0.05) time-effects within each group were observed: markers of muscle damage, cadence and perception of pain increased, while TNF-a, isometric and dynamic force production and stride-length decreased. Creatine-kinase at 24H-post and 48H-post were correlated (p < 0.05, r range = −0.57 to 0.55) with pain perception, stride-length, and cadence at 24H-post and 48H-post. Significant (p < 0.05) correlations were observed between isometric force production at all time-points and IL-6 at 48H-post DHR (r range = −0.62 to (−0.74).

Conclusion: Y and MA active male amateur athletes recover in a comparable manner following an EIMD downhill protocol. These results indicate that similar recovery strategies can be used by trainees from both age groups following an aerobic-based EIMD protocol.

Effect of an Ultra-Endurance Event on Cardiovascular Function and Cognitive Performance in Marathon Runners

Background

Ultra-marathon running participation has become increasingly more popular in recent years; however, there is inconclusive evidence concerning the effects of participation on cognition and cardiovascular function. The purpose of this study was to examine alterations in cardiovascular function and cognitive performance and their association in ultra-marathon runners prior to and following an ultra-endurance event.

Methods

In total, 24 runners (19 males and 5 females) participated in an ultra-marathon race (FatDog120) held in British Columbia, Canada. Participants competed in varying races distances [48 km (n = 2), 80 km (n = 7), 113 km (n = 3), and 193 km (n = 12)]. Cognition was assessed prior to and upon race completion using simple reaction time, choice reaction time, discrimination reaction time, and recognition memory (% correct). Cardiovascular function was assessed prior to and upon race completion using radial applanation tonometry for diastolic pulse contour examination.

Results

Cognitive performance displayed significantly (p < 0.001) slower reaction times post-race for simple (30.2%), discrimination (22.7%), and choice reaction time (30.5%), as well as a significant (p < 0.05) reduction in memory test performance (−8.2%). A significant association between systemic vascular resistance and choice reaction time was observed post-race (r = 0.41, p < 0.05). Significant changes in post-race cardiovascular function were observed in resting heart rate (31.5%), cardiac output (27.5%), mean arterial blood pressure (−5.6%), total systemic resistance (−17.6%), systolic blood pressure (−7.0%), pulse pressure (−11.2%), and rate pressure product (22.4%). There was evidence of enhanced cardiovascular function being associated with improved cognitive performance before and after the ultra-endurance event.

Conclusion

Ultra endurance running is associated with marked impairments in cognitive performance that are associated (at least in part) with changes in cardiovascular function in healthy adults.

Physical activity and exercise recommendations for people receiving dialysis: A scoping review

INTRODUCTION

Remaining physically active is important to patients undertaking dialysis, however, clinical recommendations regarding exercise type, timing, intensity, and safety precautions vary. The purpose of this scoping review was to analyse and summarise recommendations for physical activity and exercise for people undertaking dialysis and identify areas that require further research or clarification.

MATERIALS AND METHODS

A scoping review of literature from five bibliographic databases (Medline, Scopus, Web of Science, CINAHL, and SPORTDiscus) was conducted. Eligible articles included consensus guidelines, position statements, reviews, or clinical practice guidelines that included specific physical activity and exercise recommendations for people undertaking dialysis. Key search terms included "kidney disease" OR "kidney failure" OR "chronic kidney disease" OR "end stage kidney disease" AND guideline* OR consensus OR "position statement" OR prescription OR statement AND exercise OR "physical activity". Hand searching for relevant articles in all first twenty quartile 1 journals listed on SCImago under 'medicine-nephrology' and 'physical therapy, sports therapy and rehabilitation' using the terms 'exercise and dialysis' was undertaken. Finally, home pages of key societies and professional organisations in the field of sports medicine and nephrology were searched.

RESULTS

The systematic search strategy identified 19 articles met the inclusion criteria. Two were specific to pediatric dialysis and three to peritoneal dialysis. Whilst many publications provided recommendations on aerobic exercise, progressive resistance training and flexibility, few provided explicit guidance. Recommendations for the intensity, duration and frequency of aerobic and resistance training varied. Discrepancies or gaps in guidance about precautions, contraindications, termination criteria, progression, and access site precautions were also apparent.

CONCLUSION

Future guidelines should include specific guidance regarding physical activity, safety precautions, and timing and intensity of exercise for individuals who undertake dialysis. Collaborative multidisciplinary guideline development and appropriate exercise counselling may lead to increased participation in physical activity and exercise and facilitate better patient outcomes.

State of Knowledge on Molecular Adaptations to Exercise in Humans: Historical Perspectives and Future Directions

For centuries, regular exercise has been acknowledged as a potent stimulus to promote, maintain, and restore healthy functioning of nearly every physiological system of the human body. With advancing understanding of the complexity of human physiology, continually evolving methodological possibilities, and an increasingly dire public health situation, the study of exercise as a preventative or therapeutic treatment has never been more interdisciplinary, or more impactful. During the early stages of the NIH Common Fund Molecular Transducers of Physical Activity Consortium (MoTrPAC) Initiative, the field is well-positioned to build substantially upon the existing understanding of the mechanisms underlying benefits associated with exercise. Thus, we present a comprehensive body of the knowledge detailing the current literature basis surrounding the molecular adaptations to exercise in humans to provide a view of the state of the field at this critical juncture, as well as a resource for scientists bringing external expertise to the field of exercise physiology. In reviewing current literature related to molecular and cellular processes underlying exercise-induced benefits and adaptations, we also draw attention to existing knowledge gaps warranting continued research effort. © 2021 American Physiological Society. Compr Physiol 12:3193-3279, 2022.

Optimizing sprint interval exercise for post-exercise hypotension: A randomized crossover trial

This study aimed to examine the effects of manipulating the rest intervals during sprint interval training (SIT) on post-exercise hypotension and within-session oxygen consumption.Thirty healthy, trained adults (aged 30.9 ± 8.7 years; 14 males, 16 females; BMI 22.1 ± 2.3 kg/m²; VO₂max 50.7 ± 7.8 ml/kg/min) completed two different SIT protocols (4x 30-seconds all-out cycling sprints) with a one-week washout period. Sprint bouts were separated by either 1 (R1) or 3 (R3) minutes of active recovery. Both before and throughout the 45 minutes after the training, peripheral systolic (pSBP) and diastolic (pDBP) blood pressure, central systolic (cSBP) and diastolic (cDBP) blood pressure, aortic pulse wave velocity (aPWV), stroke volume (SV), and heart rate (HR) were assessed. Throughout the SIT protocols, oxygen consumption (VO₂) was monitored.There were no significant differences in time spent at 75%, 85%, 95%, and 100% of maximal VO₂ between R1 and R3. After R3, there was a significant reduction in pSBP, pDBP, cSBP, cDBP, and aPWV. After R1, there were no changes in the respective parameters. There were significant interaction effects in pSBD (p<0.001), pDBP (p<0.001), cSBP (p<0.001), cDBP (p=0.001), and aPWV (p=0.033). HR significantly increased after both conditions. Only R1 resulted in a significant reduction in SV.Longer resting intervals during SIT bouts seem to result in more substantial post-exercise hypotension effects. Time spent at a high percentage of maximal VO₂ was not affected by rest interval manipulation.

Gaming Instead of Training? Exergaming Induces High-Intensity Exercise Stimulus and Reduces Cardiovascular Reactivity to Cold Pressor Test

Introduction

The present study assessed if an exercise session in an innovative exergame can modulate hemodynamic reactivity to a cold pressor test (CPT) to a similar extent as a typical moderate endurance training (ET). Furthermore, cardiorespiratory, and affective responses of an exergame session and an ET were compared.

Methods

Twenty-seven healthy participants aged 25 ± 4 years (48% female; BMI 23.0 ± 2.1 kg/m2) participated in this cross-sectional study. All participants completed both an ET on a treadmill and training in the ExerCube (ECT). HR and oxygen consumption were recorded during both training sessions. Before and after both exercise sessions, the hemodynamic reactivity to a CPT was determined.

Results

During ECT, HR, oxygen consumption, energy expenditure, and the metabolic equivalent of the task were significantly higher than those obtained during ET (p &lt; 0.001). With regard to the CPT, the participants showed significantly lower responses in peripheral systolic (p = 0.004) and diastolic blood pressure (p = 0.009) as well as central systolic (p = 0.002) and diastolic BP (P = 0.01) after ECT compared to ET. The same was true for pulse wave velocity (p = 0.039).

Conclusion

The ECT induced a significantly higher exercise stimulus compared to the ET. At the same time, it attenuated hemodynamic stress reactivity. The ECT presents a relevant training stimulus that modulates cardiovascular reactivity to stress, which has been proven as a predictor for the development of hypertension.

Trial Registration

ISRCTN registry, ISRCTN43067716, 14 April 2020, Trial number: 38154.

A Game-Based Approach to Lower Blood Pressure? Comparing Acute Hemodynamic Responses to Endurance Exercise and Exergaming: A Randomized Crossover Trial

The present randomized crossover study aimed to determine whether an exergaming session in an innovative, functional fitness game could be an effective exercise approach that elicits favorable blood pressure (BP) responses, such as a typical moderate endurance exercise (ET). Therefore, acute hemodynamic responses after a training session in the ExerCube and an ET on a treadmill were assessed and compared. Twenty-eight healthy recreational active participants (13 women; aged 24.8 ± 3.9 years) completed an exergaming session (EX) and an ET in a randomized and counterbalanced order. Before and throughout the 45 min after the training, the peripheral and central BP were measured. After the ET, there was a moderate decrease in both peripheral systolic (-1.8 mmHg; p = 0.14) and diastolic (-0.8 mmHg; p = 0.003), as well as central diastolic (-1.5 mmHg; p = 0.006) pressure compared to the resting value before the exercise. After the EX, there was a significant decrease in peripheral systolic (-6.3 mmHg; p < 0.001) and diastolic (-4.8 mmHg; p < 0.001), as well as central systolic (-5.8 mmHg; p < 0.001) and diastolic (-5.3 mmHg; p < 0.001) pressure compared to baseline. The interaction effects showed significant differences in peripheral and central systolic BP as well as in peripheral diastolic BP (p = 0.05). The EX seems to be an effective training approach that triggers relevant peripheral and central BP-responses, which are more pronounced than after a typical ET. Therefore, the ExerCube can be a time-efficient training tool to improve cardiovascular health.

Acute Effects of Heart Rate-Controlled Exergaming on Vascular Function in Young Adults

Objective: Acute and regular moderate-intensity endurance exercise (MIEE) is known to positively affect vascular function. The present study assessed if an exercise session in an innovative exergame called the ExerCube can induce similar vascular reactions as an MIEE session. Materials and Methods: Twenty-eight healthy recreationally active participants (13 females and 15 males; aged 24.8 ± 3.9 years; with body mass index 23.2 ± 2.3 kg/m²) completed an exergaming session (EGS) in the ExerCube (25 minutes) and an MIEE session on a treadmill (35 minutes, 65%-70% of maximal heart rate [HR]) in a randomized order. Both before and throughout the 45 minutes after the training sessions, pulse wave velocity (PWV), total peripheral resistance (TPR), stroke volume (SV), and HR were recorded. The study was approved by the Research Ethics Board of the Martin-Luther-Universität Halle-Wittenberg (Medical Faculty of the Martin-Luther-Universität 2019-177). Results: There were different hemodynamic responses to both types of exercises. PWV was significantly decreased 45 minutes after the EGS (P < 0.001). No significant changes were detected after MIEE (P = 0.109). TPR was significantly lower after both exercise sessions (P < 0.01). Only the EGS resulted in a significant decrease in SV 15 minutes after exercise (P < 0.001). The HR was significantly (P < 0.05) higher after both exercise sessions. After the EGS, the increase in HR was still significantly higher (P = 0.011) 45 minutes after the session. The interaction effects revealed significant differences in PWV (15 minutes, P = 0.035; 30 minutes, P = 0.004; and 45 minutes, P < 0.001), favoring the EGS. Conclusion: The EGS seems to induce a relevant exercise stimulus that can modulate vascular function. Therefore, this exergame may present an effective tool for prevention of cardiovascular diseases.

Central Hypovolemia Detection During Environmental Stress-A Role for Artificial Intelligence?

The first step to exercise is preceded by the required assumption of the upright body position, which itself involves physical activity. The gravitational displacement of blood from the chest to the lower parts of the body elicits a fall in central blood volume (CBV), which corresponds to the fraction of thoracic blood volume directly available to the left ventricle. The reduction in CBV and stroke volume (SV) in response to postural stress, post-exercise, or to blood loss results in reduced left ventricular filling, which may manifest as orthostatic intolerance. When termination of exercise removes the leg muscle pump function, CBV is no longer maintained. The resulting imbalance between a reduced cardiac output (CO) and a still enhanced peripheral vascular conductance may provoke post-exercise hypotension (PEH). Instruments that quantify CBV are not readily available and to express which magnitude of the CBV in a healthy subject should remains difficult. In the physiological laboratory, the CBV can be modified by making use of postural stressors, such as lower body "negative" or sub-atmospheric pressure (LBNP) or passive head-up tilt (HUT), while quantifying relevant biomedical parameters of blood flow and oxygenation. Several approaches, such as wearable sensors and advanced machine-learning techniques, have been followed in an attempt to improve methodologies for better prediction of outcomes and to guide treatment in civil patients and on the battlefield. In the recent decade, efforts have been made to develop algorithms and apply artificial intelligence (AI) in the field of hemodynamic monitoring. Advances in quantifying and monitoring CBV during environmental stress from exercise to hemorrhage and understanding the analogy between postural stress and central hypovolemia during anesthesia offer great relevance for healthy subjects and clinical populations.

Consistency of hemodynamic and autonomic mechanisms underlying post-exercise hypotension

Post-exercise hypotension (PEH) is a clinically relevant phenomenon, but its mechanisms vary between different studies and between the participants within each study. Additionally, it is possible that PEH mechanisms are not consistent in each individual (i.e. within-individual variation), which has not been investigated yet. Thus, the aim of the current study was to assess the within-individual consistency of PEH hemodynamic and autonomic mechanisms. For that, 30 subjects performed 4 sessions divided in 2 blocks (test and retest). In each block, an exercise (cycling, 45 min, 50%VO₂peak) and a control (seated rest, 45 min) session was randomly conducted. Blood pressure (BP) and its mechanisms were evaluated pre- and post-interventions. In each block, individual responses were calculated as post-exercise minus post-control, and a response was considered present when its magnitude reached the typical error of the measurement. Consistencies were evaluated by comparing test and retest responses through kappa coefficient (k). PEH consistency was calculated using role sample, while mechanisms consistency was evaluated in those with consistent PEH. Twenty-one (70%) participants showed consistent PEH, 5 (17%) presented PEH in only test or retest and 4 (13%) had absent PEH response, characterising a good consistency (k = 0.510). Regarding mechanisms' responses, good consistency was found for heart rate (k = 0.456), sympathovagal balance (k = 0.438), and baroreflex sensitivity (k = 0.458); while systemic vascular resistance (k = 0.152), cardiac output (k = -0.400), stroke volume (k = -0.055), and sympathetic vasomotor modulation (k = -0.096) presented marginal consistencies. Thus, PEH is a highly consistent physiological phenomenon, although its mechanisms present variable consistencies.

Acute effects of long-distance races on heart rate variability and arterial stiffness: A systematic review and meta-analysis

This study systematically reviewed and quantified the effects of running a long-distance race (LDR) on heart rate variability (HRV) and arterial stiffness (AS). All types of races of a distance equal to or greater than a marathon (≥42.2 km) were included. A total of 2,220 articles were identified, 52 were included in the qualitative analysis, and 48 were meta-analysed. The standardised mean difference pre- and post-race of various time-domain and frequency-domain indices of HRV, mean arterial blood pressure (MAP), systolic blood pressure (SBP), diastolic blood pressure (DBP) and carotid-femoral pulse wave velocity (cfPWV) was calculated. Regarding HRV, there was a significant decrease in most of the variables considered as markers of parasympathetic activity, indicating a shift of autonomic balance towards a reduced vagal tone. Regarding vascular variables, there was a significant drop in blood pressure and reduced AS. In conclusion, running an LDR seems to have a considerable acute effect on the autonomic nervous system, haemodynamics, and vascular properties. The observed effects could be categorised within the expected acute responses to long-lasting, strenuous exercise.

Exercise to Reduce Anthracycline-Mediated Cardiovascular Complications in Breast Cancer Survivors

While developments in cancer therapeutics have greatly reduced morbidity and mortality in females with breast cancer, it comes at a cost of an increased risk of cardiovascular complications. In particular, anthracyclines, like doxorubicin, which are a mainstay of current chemotherapy regimens, are associated with dose-dependent cardiotoxicity. Exercise has been widely accepted as an effective intervention in reducing cardiovascular risk in a variety of different clinical conditions. However, the benefits of exercise in anthracycline-mediated cardiotoxicity are not clearly understood. First, this review discusses the pre-clinical studies which have elucidated the cardioprotective mechanisms of aerobic and resistance exercise in improving cardiovascular function in the setting of anthracycline treatment. Next, it aims to summarize the results of aerobic and resistance exercise clinical trials conducted in females with breast cancer who received anthracycline-based chemotherapy. The review further discusses the current exercise guidelines for women undergoing chemotherapy and contraindications for exercise. Finally, the review addresses gaps in research, specifically the need for further clinical trials to establish a recommended exercise prescription within this patient population.

Effects of physical exercise on baroreflex sensitivity and renal sympathetic nerve activity in chronic nicotine-treated rats

Chronic nicotine exposure may increase cardiovascular risk by impairing the cardiac autonomic function. Besides, physical exercise (PE) has shown to improve cardiovascular health. Thus, we aimed to investigate the effects of PE on baroreflex sensitivity (BRS), heart rate variability (HRV), and sympathetic nerve activity (SNA) in chronically nicotine-exposed rats. Male Wistar rats were assigned to four independent groups: Control (treated with saline solution), Control+Ex (treated with saline and submitted to treadmill training), Nicotine (treated with Nicotine), and Nicotine+Ex (treated with nicotine and submitted to treadmill training). Nicotine (1 mg·kg-1) was administered daily for 28 consecutive days. PE consisted of running exercise (60%-70% of maximal aerobic capacity) for 45 min, 5 days per week, for 4 weeks. At the end of the protocol, cardiac BRS, HRV, renal SNA (rSNA), and renal BRS were assessed. Nicotine treatment decreased absolute values of HRV indexes, increased low frequency/high frequency ratio of HRV, reduced the bradycardic and sympatho-inhibitory baroreceptor reflex responses, and reduced the rSNA. PE effectively restored time-domain HRV indexes, the bradycardic and sympatho-inhibitory reflex responses, and the rSNA in chronic nicotine-treated rats. PE was effective in preventing the deterioration of time-domain parameters of HRV, arterial baroreceptor dysfunction, and the rSNA after nicotine treatment.

Exercise Improves Endothelial Function via the lncRNA MALAT1/miR-320a Axis in Obese Children and Adolescents

Background

Endothelial dysfunction commonly occurs in obese children and adolescents, leading to an increased risk of cardiovascular diseases. Exercise has significant protective effects against endothelial dysfunction through regulating some noncoding RNAs. This study aimed to investigate the relationship of long noncoding RNA MALAT1 and microRNA-320a (miR-320a) with the exercise-induced improvement of endothelial dysfunction in obese children and adolescents.

Methods

Sixty obese children and adolescents were included in this study, including 40 cases that received 12-week exercise training and 20 cases that received only diet control. The anthropometric and blood indices before and after exercise were recorded and compared, and the endothelial dysfunction was evaluated by examining the levels of markers, including VCAM-1, ICAM-1, and E-selectin, using an ELISA assay. The expression levels of noncoding RNAs were assessed using real-time quantitative PCR, and their correlation with patients' recorded indices and endothelial dysfunction markers was analyzed.

Results

The 12-week exercise training significantly decreased the levels of VCAM-1, ICAM-1, and E-selectin and could inhibit MALAT1 but promote miR-320a expression in obese children and adolescents. The expression of MALAT1 and miR-320a was correlated with the changes in the anthropometric and blood indices of obese children and adolescents, and their correlations with endothelial dysfunction markers were obtained.

Conclusion

All the data revealed that exercise has significantly protective effects against endothelial dysfunction and can regulate the expression of the MALAT1/miR-320a axis. MALAT1 and miR-320a were correlated with endothelial dysfunction markers, indicating that the MALAT1/miR-320a axis may be related with the alleviating effects of exercise on endothelial function in obese children and adolescents.

LncRNA MALAT1/miR-320a axis is associated with exercise-induced improvement of endothelial dysfunction in obese children

BACKGROUND

Endothelial dysfunction commonly occurs in obese children, leading to increased risk of cardiovascular diseases. Exercise has protective effects against endothelial dysfunction through regulating some noncoding RNAs. This study aimed to investigate the relationship of long noncoding RNA MALAT1 and microRNA-320a (miR-320a) with the exercise-induced improvement of endothelial dysfunction in obese children.

METHODS

Sixty obese children were included in this study, and 40 cases received a 12-week exercise training. The morphological and blood indices before and after exercise were recorded and compared, and the endothelial dysfunction was evaluated by examining the levels of VCAM-1, ICAM-1, E-selectin, IL-6 and TNF-α using ELISA kits. The expression of noncoding RNAs was assessed using Real-Time quantitative PCR. Endothelial cells were used to explore the effects of MALAT1 and miR-320a on endothelial function.

RESULTS

The 12-well exercise training decreased the levels of VCAM-1, ICAM-1 and E-selectin, and inhibited MALAT1 but promoted miR-320a expression in obese children. The expression of MALAT1 and miR-320a was correlated with the changes of morphological and blood indices in obese children, and their correlations with endothelial dysfunction markers were obtained. Additionally, MALAT1 overexpression or miR-320a reduction led to inhibited proliferation and increased inflammation in HUVECs.

CONCLUSION

All the data revealed that exercise has significantly protective effects against endothelial dysfunction, and can regulate the expression of the MALAT1/miR-320a axis. MALAT1 and miR-320a were correlated with endothelial dysfunction, indicating that the MALAT1/miR-320a axis may be related with the alleviating effects of exercise on endothelial function in obese children.

Vagal reactivation after a cardiac rehabilitation session associated with hydration in coronary artery disease patients: crossover clinical trial

This study aimed to investigate the hydration influence on the autonomic responses of coronary artery disease subjects in the immediate recovery period after a cardiovascular rehabilitation session, in view of the risks of a delayed autonomic recovery for this population. 28 males with coronary artery disease were submitted to: (I) Maximum effort test; (II) Control protocol (CP), composed by initial rest, warm-up, exercise and passive recovery; (III) Hydration protocol (HP) similar to CP, but with rehydration during exercise. The recovery was evaluated through the heart rate (HR) variability, HR recovery and by the rate of perceived exertion and recovery. The main results revealed that the vagal reactivation occurred at the first 30 s of recovery in HP and after the first minute in CP. A better behavior of the HR at the first minute of recovery was observed in HP. The rate of perceived exertion had a significant decrease in the first minute of recovery in HP, while in CP this occurred after the third minute. In conclusion, despite an anticipated vagal reactivation found at HP, these results should be analyzed with caution as there were no significant differences between protocols for all variables and the effect sizes were small.

Acute Running and Coronary Heart Disease Risk Markers in Male Cigarette Smokers and Nonsmokers: A Randomized Crossover Trial

PURPOSE

Cigarette smoking is an independent risk factor for coronary heart disease and is associated with impaired postprandial metabolism. Acute exercise reduces postprandial lipemia and improves other coronary heart disease risk markers in nonsmokers. Less is known about responses in cigarette smokers.

METHODS

Twelve male cigarette smokers (mean ± SD; age = 23 ± 4 yr, body mass index = 24.9 ± 3.0 kg·m-2) and 12 male nonsmokers (age = 24 ± 4 yr, body mass index = 24.1 ± 2.0 kg·m-2) completed two, 2-d conditions (control and exercise) in a randomized crossover design. On day 1, participants rested for 9 h (0800-1700) in both conditions except a 60-min treadmill run (65% ± 7% peak oxygen uptake, 2.87 ± 0.54 MJ) was completed between 6.5 and 7.5 h (1430-1530) in the exercise condition. On day 2 of both conditions, participants rested and consumed two high-fat meals over 8 h (0900-1700) during which 13 venous blood samples and nine resting arterial blood pressure measurements were collected.

RESULTS

Smokers exhibited higher postprandial triacylglycerol and C-reactive protein than nonsmokers (main effect group effect size [Cohen's d] ≥ 0.94, P ≤ 0.034). Previous day running reduced postprandial triacylglycerol, insulin, and systolic and diastolic blood pressure (main effect condition d ≥ 0.28, P ≤ 0.044) and elevated postprandial nonesterified fatty acid and C-reactive protein (main effect condition d ≥ 0.41, P ≤ 0.044). Group-condition interactions were not apparent for any outcome across the total postprandial period (0-8 h; all P ≥ 0.089), but the exercise-induced reduction in postprandial triacylglycerol in the early postprandial period (0-4 h) was greater in nonsmokers than smokers (-21%, d = 0.43, vs -5%, d = 0.16, respectively; group-condition interaction P = 0.061).

CONCLUSIONS

Acute moderate-intensity running reduced postprandial triacylglycerol, insulin, and resting arterial blood pressure the day after exercise in male cigarette smokers and nonsmokers. These findings highlight the ability of acute exercise to augment the postprandial metabolic health of cigarette smokers and nonsmokers.