High Cardiorespiratory Fitness Groups Research Articles

Influence of Cardiorespiratory Fitness on Cardiac Autonomic Recovery Among Active-Duty Firefighters.

Abstract Cornell, DJ, Flees, RJ, Shemelya, CM, and Ebersole, KT. Influence of cardiorespiratory fitness on cardiac autonomic recovery among active-duty firefighters. J Strength Cond Res XX(X): 000–000, 2023—It has been suggested that an inability of the autonomic nervous system (ANS) to recover after strenuous events is a potential cause of sudden cardiac death among firefighters. The purpose of this study was to examine the influence of cardiorespiratory fitness (CRF) on the heart rate recovery (HRR) kinetics of firefighters. Thirty-seven male career active-duty firefighters completed both a submaximal step test and a maximal treadmill graded exercise test. A monoexponential curve was fit to postexercise submaximal and maximal HRR data of each subject. Subjects were placed into Low CRF (n = 13) and High CRF (n = 24) groups based on the standard peak aerobic capacity (V̇O2peak) criterion of <42 ml·kg−1·minute−1 and ≥42 ml·kg−1·minute−1, respectively. After controlling for age and body mass index, CRF was significantly (p < 0.05) correlated with the decay rate ( ) and asymptote ( ) after submaximal exercise (r sp = −0.556; r sp = −0.637, respectively), as well as the , , and amplitude ( ) after maximal exercise (r sp = −0.353; r sp = −0.416; r sp = 0.603, respectively). High CRF firefighters demonstrated a significantly faster after both submaximal (p = 0.003) and maximal exercise (p = 0.043), a lower after submaximal exercise (p = 0.002), and a higher after maximal exercise (p = 0.001), than Low CRF firefighters. Greater CRF was associated with enhanced HRR kinetics after submaximal and maximal exertion, suggesting that CRF may positively influence the ANS recovery of firefighters.

Relationship between Cardiorespiratory Fitness and Executive Function in Young Adults: Mediating Effects of Gray Matter Volume

We evaluated the association between cardiorespiratory fitness (CRF) and executive function (EF) in young adults and the mediating effects of GMV on this relationship. This study involved 217 college students. An incremental load exercise program was used to evaluate VO2max. EF was estimated by the Flanker task, the 2-back task, and the more-odd shifting task, while structural magnetic resonance and region-based morphometry (RBM) were used to analyze GMV. The high CRF group had a shorter updating reaction time (RT) (p ≤ 0.05). CRF was positively correlated with the right orbital part of the middle frontal gyrus (ORBmid.R) GMV (p ≤ 0.05). ORBmid.R GMV was negatively correlated with updating RT (p ≤ 0.05). Model 4 in SPSS was used to assess the mediating effects of ORBmid.R GMV between CRF and updating RT. ORBmid.R GMV was established to have a partially mediating role between CRF and updating RT, which accounted for 19.6% of the total effect value. These findings indicate that the negative correlation between CRF and EF was significant, and ORBmid.R GMV played a mediating role in the relationship between CRF and EF, providing new evidence toward comprehensively revealing that CRF promotes EF performance.

Cardiorespiratory Fitness Level Alters Blood Pressure Responses Induced By Histamine H1- And H2-receptor Blockade During Dynamic Exercise

INTRODUCTION: Epidemiological studies have reported that greater cardiorespiratory fitness (CRF) is associated with lower blood pressure (BP). Histamine receptor-mediated peripheral vasodilation contributes to post-exercise hypotension and lowing exercising BP responses. Previously, our laboratory found that overactive BP responses to exercise were induced by the inability of histamine receptors in individuals with prehypertension. However, it is still unknown that CRF can impact BP responses elicited by the inability of the receptors. PURPOSE: This study was to assess whether aerobic fitness is effective in lowering excessive BP responses induced by the blockade of histamine receptors METHODS: In twelve male and female subjects (6 high CRF and 6 low CRF), we examined the effects of histamine H1- and H2- receptor blockades on heart rate (HR), stroke volume (SV), cardiac output (CO), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), and total peripheral resistance (TPR) at workloads corresponding to 40% and 60% workloads of VO2peak during cycling exercise. RESULTS: Our study indicated that compared to the high CRF group, changes in MAP from the baselines were higher in the low CRF group before the blockade at each workload (40%: D14±2 vs. 8±1 mmHg; 60%: D21±3 vs. 15±2 mmHg). The changes in MAP in response to the blockade during exercise were substantially lower in the high CRF group (40%: D18±2 vs. 11±1 mmHg; 60%: D29±3 vs. 19±2 mmHg). CONCLUSIONS: Our study suggests that an improvement in CRF likely reduces exaggerated BP responses elicited due to the inability of histamine receptors in pathological conditions such as prehypertension and hypertension.

P-103 Physical fitness is positively associated with sperm quality in healthy young men

Abstract Study question Do sperm quality parameters differ between “high” and “low” cardiorespiratory fitness (CRF) and muscular strength levels in healthy young men? Summary answer Self-reported CRF was positively associated with sperm count and concentration, while muscular strength (objectively measured and self-reported) did not correlate with seminal parameters. What is known already Physical activity (i.e., any body movement that results in energy expenditure) levels are positively associated with sperm quality parameters in healthy men. In this context, physical fitness, which is modifiable by physical activity, is a powerful marker of health that integrates several body functions such as hematocirculatory, skeletomuscular, phsychoneurological and endocrine-metabolic. In particular, the main components of physical fitness (i.e., CRF and muscular strength) have been negatively related to the risk of all-cause mortality in any age population. However, the association of CRF and muscular strength with sperm quality parameters in healthy young men is unknown. Study design, size, duration This cross-sectional study included 253 healthy men (age= 22.63 ± 5.04 years, BMI= 22.84 ± 1.33). Semen samples and physical fitness assessment were performed between March 2019 and July 2021 at the sperm biobank (Ceifer Biobank – NextClinics). The study was approved by the Ethics Committee of Investigación Biomédica de Andalucía. Participants/materials, setting, methods CRF was self-reported using the The International FItness Scale (IFIS). Muscular strength was objectively assessed using a handgrip dynamometer and self-reported with IFIS. Semen samples were analysed by clinical technicians to determine sperm count, sperm concentration and progressive motility. Analysis of covariance (ANCOVA) was performed to obtain adjusted mean differences on sperm quality parameters between high and low CRF and muscular strength groups after including age and body mass index as confounders. Main results and the role of chance Men with higher CRF presented increased sperm count and concentration compared to men with lower CRF values (adjusted mean differences 43.581 x 106 [2.630, 84.532; 95% confidence interval] and 10.131 x 106/ml [0.799, 19.463; 95% confidence interval]; both p < 0.05). Muscular strength (objectively measured and self-reported) was not associated with any semen quality parameter (all p > 0.05) when including age and body mass index as covariates. Limitations, reasons for caution This study reported a positive association between self-reported CRF using IFIS questionnaire and sperm count and concentration in healthy young men. Although the validity of the self-reported CRF using IFIS has been widely proved in healthy young adults, objectively measured CRF is needed to further confirm our findings. Wider implications of the findings Infertility has increased in the last decades. Therefore, more research is needed to identify health indicators that affect sperm quality. Our results suggest that self-reported CRF could contribute to the identification of young men with poor seminal quality and a higher risk of infertility later in life. Trial registration number NA

High fitness levels attenuate the increased risk of heart failure due to low socioeconomic status: A cohort study

High fitness levels attenuate the increased risk of heart failure due to low socioeconomic status: A cohort study

Association between Cardiorespiratory Fitness, Muscle Strength, and Non-Alcoholic Fatty Liver Disease in Middle-Aged Men

Background: Nonalcoholic fatty liver disease (NAFLD) occurs when more than 5% of fat accumulates in the liver parenchyma without excess alcohol consumption. The objective of this study is to investigated the association between cardiorespiratory fitness (CRF), muscle strength (MS), and NAFLD. Methods: The subjects of this study were 1325 males aged 40–50 who had visited the National Fitness Center located in the Republic of Korea from 2017 to 2019. Abdominal ultrasonography testing was used for NAFLD diagnosis. For CRF, an MS test was used to measure maximal oxygen intake and grip strength. CRF and MS were classified into 3 quartiles (high, middle, low-level). In addition, both the CRF level and MS level were classified into 9 quadrants. Results: With confounding factors (age, body mass index, exercise, smoking) controlled, there was no relative risk of NAFLD between middle and high levels of CRF (95% CI, 0.92–2.17). However, the relative risk of NAFLD in the case of low-level CRF was 1.63-fold (95% CI, 1.03–2.60, p < 0.05) higher than that in the case of high-level CRF. Meanwhile, there was no significant difference between middle-level MS (95% CI, 0.68–1.65) and high-level MS (95% CI, 0.84–1.99) in terms of NAFLD relative risk. The NAFLD relative risk in the case of low-level CRF/MS was 2.27-fold (95% CI, 0.94–1.99, p < 0.05) higher than that of high-level CRF/MS. Conclusions: The low CRF and MS group had a higher risk of NAFLD compared with the high CRF and MS group. Maintenance of high CRF and MS may be beneficial in preventing NAFLD.

Greater cardiorespiratory fitness reduces incidence of atrial fibrillation: a meta-analysis

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Atrial Fibrillation (AF) is the most common sustained cardiac arrhythmia affecting 1-2% of the global population, with the prevalence of AF increasing dramatically over the past two decades. Although low levels of cardiorespiratory fitness (CRF) and physical activity are predictive of cardiovascular disease onset and mortality, only recently has this emerged as a potential risk factor for AF. Purpose The aim of this meta-analysis was therefore to quantify the relationship between CRF, measured by a symptom limited exercise stress test, and incident AF. We hypothesised that there would be an inverse relationship between CRF and the incidence of AF. Methods The systematic literature review was conducted using PUBMED, MEDLINE and EMBASE databases, with seven studies meeting the inclusion criteria. A random-effects meta-analysis was then used to compare the multivariate risk estimates of the lowest CRF group from each cohort with the group of the highest CRF. Results Data from 206,925 individuals (55.8% males) was used for analysis with a mean age of 55 ± 2.5 years and a mean follow-up period of 10.3 ± 5 years. The total number of AF events across the studies was 19,913. The overall pooled risk of AF in the high-CRF group versus the low-CRF group showed a significant lower risk of incident AF in those with high-CRF (OR: 0.52, 95% CI, 0.44-0.605, p < 0.001). There was evidence of statistical heterogeneity between the studies (I2 = 81%, p < 0.001). AF incidence rates demonstrated an overall decline in rates across the CRF quartiles from low to high. The mean incidence rate for low-CRF was 21 ± 13.4 compared to 6.9 ± 0.7 per 1000 person-years for the high CRF group (p = 0.03). Conclusion There is an inverse association between a lower CRF and an increased risk of AF, with a higher level of CRF protective against AF. This study highlights that low-CRF may be an additional risk factor for AF along with already other established lifestyle-based risk factors such as obesity and hypertension. Exercise interventions should be promoted as a primary prevention strategy in those at risk of developing AF with known risk factors. Future studies are warranted to identify the mechanism(s) through which improved CRF confers a reduction in AF incidence. Abstract Figure. AF risk between high and low-CRF

Cardiorespiratory fitness and electroanatomical remodelling in patients with atrial fibrillation

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Atrial fibrillation (AF) is the most common clinically-relevant arrhythmia. Its initiation and maintenance is linked to the presence cardiovascular risk factors such as hypertension and obesity. Higher cardiorespiratory fitness (CRF) has been associated with a better prognosis. However, specific electroanatomical features associated with baseline CRF have not been described. Purpose Compare electroanatomical substrate across exercise capacity levels in patients with AF Methods Patients referred for de novo AF radiofrequency ablation at the Centre for Heart Rhythm Disorders from August 2017 until June 2020 were screened for inclusion and CRF was evaluated in metabolic equivalents (METs) by a symptom-limited maximal treadmill exercise test using the standard Bruce protocol prior to ablation. Predicted CRF was calculated based on established equations and patients were categorized according to the percentage of predicted CRF achieved; low (<85%), adequate (85-100%) and high (>100%). Total mean and regional peak-to-peak bipolar voltages, percent of low voltage areas (% LVA), conduction velocity (CV) and percent of complex fractionated electrograms (% CFE) in sinus rhythm were compared across groups. Results There were no between-group differences in baseline characteristics, medication use or echocardiographic features. Total mean voltage was significantly lower in the low CRF group compared to both adequate and high CRF. Compared to the high CRF group, roof (3.25 ± 1.2 mV vs 1.9 ± 1.3 mV, p < 0.05), posterior (3.8 ± 1.8 mV vs 1.7 ± 0.9 mV, p < 0.001) and inferior mean voltages (3.4 ± 2 mV vs 1.6 ± 0.7 mV, p < 0.05) were significantly lower in the low CRF group (figure 1A). Furthermore, compared with the adequate CRF group, mean voltages were significantly lower in the posterior (3.7 ± 1.5 mV vs 1.7 ± 0.9 mV, p < 0.001), inferior (3.4 ± 1 mV vs 1.6 ± 0.7 mV, p < 0.001) and lateral (4.2 ± 2.2 mV vs 2.1 ± 1.4 mV, p < 0.05) walls of the low CRF group. Anterior and septal mean voltages were not significantly different across CRF groups (P for trend = 0.07, 0.3 and 0.15, respectively). Conduction velocities were not significantly different across groups. The inferior %LVA was significantly higher in the low CRF (5.6 ± 6%) compared to adequate CRF group (23 ± 18%) (p < 0.05) (figure 1B). Total and regional % CFE was higher in the low CRF compared to adequate and high CRF. Conclusion Participants in the lower baseline CRF category showed significant reductions in regional voltages along with higher fractionation with preserved conduction velocities. Research on the effect of physical activity and CRF on left atrial arrhythmogenic substrate is required. Abstract Figure. Global and regional mV and % LVA by CRF

Do Patients Maintain Proper Long-Term Cardiopulmonary Fitness Levels After Cardiac Rehabilitation? A Retrospective Study Using Medical Records.

ObjectiveTo examine whether patients who participated in a cardiac rehabilitation (CR) program after hospitalization for acute coronary syndrome maintained cardiorespiratory fitness (CRF) in the community.MethodsWe conducted a retrospective study including 78 patients who underwent percutaneous coronary intervention or coronary artery bypass graft surgery at our hospital’s cardiovascular center and participated in a CR program and a 5-year follow-up evaluation. Patients were divided into a center-based CR (CBCR) group, participating in an electrocardiography-monitored exercise training in a hospital setting, and a home-based CR (HBCR) group, receiving aerobic exercise training and performed self-exercise at home.ResultsNo significant differences were found between groups (p>0.05), except the proportion of non-smokers (CBCR 59.5% vs. HBCR 31.7%; p=0.01). In both groups, the maximal oxygen consumption (VO2max) increased significantly during the first 12 weeks of follow-up and remained at a steady state for the first year, but it decreased after the 1-year follow-up. Particularly, VO2max at 5 years decreased below the baseline value in the HBCR group. In the low CRF group, the CRF level significantly improved at 12 weeks, peaked at 1 year, and was still significantly different from the baseline value after 5 years. The high CRF group did not show any significant increase over time relative to the baseline value, but most patients in the high CRF group maintained relatively appropriate CRF levels after 5 years.ConclusionContinuous support should be provided to patients to maintain optimal CRF levels after completing a CR program.

Separate and combined relationships for cardiorespiratory fitness and muscular strength with visceral fat and insulin sensitivity in adolescents with obesity.

We examined the separate and combined associations for cardiorespiratory fitness (CRF) and muscular strength (MS) with total and regional fat, and insulin sensitivity (IS) in 204 adolescents (BMI ≥85th percentile, 12-18 years) at UPMC Children's Hospital of Pittsburgh. CRF was measured by maximum oxygen consumption during a graded treadmill test. MS was quantified by combining 1-repetition maximum test for the leg and bench press. Participants were stratified as having either high or low CRF and MS based on sex-specific median split. Both high CRF and high MS groups had lower (P < 0.05) total fat after adjustment for sex, Tanner stage and ethnicity than the low CRF and MS groups (Difference: 6.6, 2.6-9.6% and 5.4, 2.4-8.3%, respectively). High CRF, but not high MS, had lower visceral (67.5 versus 77.9 cm2, P < 0.01) and intermuscular fat (3.6 versus 4.0 kg, P = 0.01) than the low CRF groups. Differences by CRF remained significant after adjustment for MS. High CRF, but not high MS, was associated (P < 0.05) with lower fasting glucose and higher IS after accounting for sex, Tanner stage and ethnicity than the low CRF group, and high CRF remained associated with these markers after adjustment for MS. High CRF is associated with lower total and regional fat, and higher IS after adjustment for MS. Novelty: CRF is associated with lower total fat, visceral and intermuscular fat, and higher insulin sensitivity adjusting for muscular strength. Muscular strength is not associated with regional body fat and insulin sensitivity after accounting for CRF.

Influence of aerobic fitness on the correspondence between heart rate variability and ventilatory threshold

The aims of this study were to verify the correspondence between heart rate variability (HRV) and ventilatory thresholds during a progressive exercise test and the relationship with low and high aerobic fitness levels. Twenty male volunteers (29.5±6.2 years; 75.9±13.0 kg; 175.0±7.4 cm) were recruited. The subjects were allocated to two groups according to their VO2max &lt;48.8 ml•kg−1•min−1 (low cardiorespiratory fitness group) (n=10) and &gt;48.81 ml•kg−1•min−1 (high cardiorespiratory fitness group) (n=10). A progressive test was performed, consisting of 3-min stages beginning at 25 watts and increasing by 25 watts every 3-min. The HRV threshold (HRVT) and ventilatory threshold (VT) analyses were performed through visual inspection. The comparisons with RMSSD values in percentage of maximum workload resulted in a higher effect size (ES) than the SDNN values. The VO2 in the high cardiorespiratory fitness group at VT (+32%), HRVTRMSSD (+27%), and HRVTSDNN (+31%) was signifi cantly higher compared to the group with low cardiorespiratory fitness. Higher values were observed for relative load (W•kg-1) at VT and HRVTSDNN in the high cardiorespiratory fitness group in comparison with the low cardiorespiratory fitness group (P&lt;0.05), but no difference for VT and HRVTRMSSD. Signifi cant correlations between at VT and HRVTSDNN (r=0.77) were found only in the low cardiorespiratory fitness group. Cardiorespiratory fitness should be regarded as a factor for HRVT evaluation. The HRVTSDNN was closer to the VT in the low cardiorespiratory fitness group than the HRVTRMSSD, however, the use of vagal modulation assessed using the HRV parameter was more sensitive to observe possible differences regarding cardiorespiratory fitness.

Influence of aerobic fitness on the correspondence between heart rate variability and ventilatory threshold

The aims of this study were to verify the correspondence between heart rate variability (HRV) and ventilatory thresholds during a progressive exercise test and the relationship with low and high aerobic fitness levels. Twenty male volunteers (29.5±6.2 years; 75.9±13.0 kg; 175.0±7.4 cm) were recruited. The subjects were allocated to two groups according to their VO2max &lt;48.8 ml•kg−1•min−1 (low cardiorespiratory fitness group) (n=10) and &gt;48.81 ml•kg−1•min−1 (high cardiorespiratory fitness group) (n=10). A progressive test was performed, consisting of 3-min stages beginning at 25 watts and increasing by 25 watts every 3-min. The HRV threshold (HRVT) and ventilatory threshold (VT) analyses were performed through visual inspection. The comparisons with RMSSD values in percentage of maximum workload resulted in a higher effect size (ES) than the SDNN values. The VO2 in the high cardiorespiratory fitness group at VT (+32%), HRVTRMSSD (+27%), and HRVTSDNN (+31%) was signifi cantly higher compared to the group with low cardiorespiratory fitness. Higher values were observed for relative load (W•kg-1) at VT and HRVTSDNN in the high cardiorespiratory fitness group in comparison with the low cardiorespiratory fitness group (P&lt;0.05), but no difference for VT and HRVTRMSSD. Signifi cant correlations between at VT and HRVTSDNN (r=0.77) were found only in the low cardiorespiratory fitness group. Cardiorespiratory fitness should be regarded as a factor for HRVT evaluation. The HRVTSDNN was closer to the VT in the low cardiorespiratory fitness group than the HRVTRMSSD, however, the use of vagal modulation assessed using the HRV parameter was more sensitive to observe possible differences regarding cardiorespiratory fitness.

Ratings of perceived exertion at the ventilatory anaerobic threshold in people with coronary heart disease: A CARE CR study.

Exercise prescription guidelines for individuals undergoing cardiovascular rehabilitation (CR) are often based on heart rate training zones and rating of perceived exertion (RPE). United Kingdom guidelines indicate that patients should exercise at an intensity of RPE 11 to 14. We aimed to determine the accuracy of this approach by comparing this RPE range with an objectively measured marker of exercise intensity, the ventilatory anaerobic threshold (VAT), and examine whether baseline directly determined cardiorespiratory fitness (CRF) affects the association between VAT and RPE. Participants underwent a maximal cardiopulmonary exercise test before an 8-week community-based CR programme. Peak oxygen uptake (V̇O2peak) and VAT were recorded, and RPE at the workload at which VAT was identified was recorded. Data were then split into tertiles, based on VO2peak, to determine whether RPE at the VAT differed in participants with low, moderate or higher CRF. We included 70 individuals [mean (SD) age 63.1 (10.0) years; body mass index 29.4 (4.0)kg/m2; 86% male]. At baseline, the mean RPE at the VAT (RPE@VAT) was 11.8 (95% confidence interval 11.0-12.6) and significantly differed between low and high CRF groups (P<0.001). The mean RPE@VAT was 10.1 (8.7-11.5), 11.8 (10.5-13.0), and 13.7 (12.5-14.9) for low, moderate and high CRF groups, respectively. When using RPE to guide exercise intensity in CR populations, one must consider the effect of baseline CRF. Mean RPEs of ∼10, 12 and 14 correspond to the VAT in low, moderate and higher-fit patients, respectively.

Higher baseline cardiorespiratory fitness is associated with lower arrhythmia recurrence and death after atrial fibrillation ablation

Cardiorespiratory fitness (CRF) has been shown to correlate with incident atrial fibrillation (AF) and AF burden. In recent years there has been increasing recognition of the pivotal role of modifying risk factors before AF ablation. The purpose of this study was to investigate whether higher baseline CRF measured using exercise stress testing (EST) was associated with improved outcomes after AF ablation. We studied 591 patients who underwent EST within 12 months before AF ablation. Patients were categorized into low (<85% predicted), adequate (85%-100% predicted), and high (>100% predicted) CRF groups. Outcomes of interest included arrhythmia recurrence, cessation of antiarrhythmic therapy, repeat hospitalization for arrhythmia, repeat rhythm control procedures, and all-cause mortality. During mean follow-up of 32 months after ablation, arrhythmia recurrence was observed in 79% of patients in the low CRF group compared to 54% in the adequate CRF group and 27.5% in the high CRF group (P <.0001). Similarly, rates of repeat arrhythmia-related hospitalization, repeat rhythm control procedures, and need for ongoing antiarrhythmic therapy were significantly lower in the high CRF group (P <.0001). Death occurred in 2.5% of patients in the high CRF group compared to 4% in the adequate CRF group and 11% in the low CRF group (P <.0001). In Cox proportional hazards analyses, high CRF was significantly associated with lower arrhythmia recurrence. Higher CRF is associated with reduced arrhythmia recurrence rates and death among patients undergoing AF ablation. Efforts should be made to enhance CRF before AF ablation.

Cardiorespiratory Fitness And The Cerebrovascular Response To A Metabolic Stimulus Following Cyclooxygenase Inhibition

Cardiorespiratory fitness (CRF) is positively associated with cerebrovascular function and cognition. We have previously shown that prostaglandins play an important role in regulating the cerebral vasodilator response to hypercapnia, and that the magnitude of change in cerebral vasodilator responses during cyclooxygenase (COX) inhibition is associated with CRF in older adults. However, it is unknown if CRF also influences the cerebrovascular response to a metabolic stimulus in older adults. PURPOSE: To determine the effects of CRF on the cerebrovascular response to a metabolic stimulus before and during COX inhibition in older adults. METHODS: Thirty-five participants completed a maximal exercise test on a cycle ergometer. Participants were split into two groups, High CRF (10 men, 8 women, age = 62 ± 5y) or Low CRF (7 men, 10 women, age = 66 ± 7y), based on the median VO2max (ml/kg/min). All participants completed two levels of the Stroop Color Word Test. Beat-to-beat mean arterial pressure (MAP) and middle cerebral artery velocity (MCAv) were measured at baseline and in response to each level of the Stroop test before and after administration of the COX inhibitor Indomethacin (INDO). The maximum MAP, MCAv, and cerebral pulsatility index (PI) responses were calculated as the highest 3-beat average during each cognitive challenge. RESULTS: There were no differences between high and low CRF groups in MCAv at rest or in response to the metabolic stimulus. There was a trend for lower PI at rest (p = 0.09) and in response to the Stroop test (p = 0.09) in the high CRF group compared with the low CRF group. During INDO, MCAv decreased (Low CRF: -29 ± 4%, High CRF: -27 ± 3%; p < 0.01) and PI increased (Low CRF: 22 ± 3%, High CRF: 17 ± 3%; p < 0.01). During INDO, MCAv at rest was not different between groups; however, PI was lower in the high CRF compared to low CRF group (Low CRF: 0.98 ± 0.05, High CRF: 0.87 ± 0.03; p < 0.05). Lastly, the change in MCAv and PI in response to the metabolic stimulus did not differ between groups. CONCLUSION: In older adults, elevated levels of CRF may lead to a lower PI at rest and in response to a metabolic stimulus. Additionally, COX inhibition did not alter the cerebrovascular response to a metabolic stimulus. Supported by NIH Grant HL118154.

Systolic Blood Pressure Responses in Relation to Cardiorespiratory Fitness of Young Adults

ABSTRACT Background: We aimed to assess systolic blood pressure (SBP) responses in relation to the cardiorespiratory fitness (CRF) levels of apparently healthy, young Nigerian adults during and after a submaximal-effort exercise test. Methods: One hundred and twelve young adults (62 males and 50 females) participated in the study and were grouped according to their CRF levels—low, moderate, and high. The participants performed submaximal ergometer exercise tests to elicit exercise and postexercise blood pressure responses. Results: Males and females with high CRF indicated significantly (P &amp;lt; 0.05) higher change of exercise SBP at peak exercise (ΔEx·SBPpeak), and post-SBP decline compared with the other CRF groups. In addition, higher (P &amp;lt; 0.05) ΔEx·SBP2min and faster SBP recovery time were observed in the high CRF group compared to low CRF group. Females with high CRF had a significantly (P &amp;lt; 0.05) higher peak oxygen pulse and energy expenditure compared with the lower CRF groups. There was a very low incidence of abnormal SBP responses among the study population. Conclusion: Greater exercise SBP responses, an indication of higher cardiac output due to greater metabolic demand, and faster SBP recovery were observed in participants with a high CRF compared with the other CRF groups. These findings suggest that regular exercise which maintains a higher CRF in young Nigerian adults may be related to a healthy SBP exercise response.

The association of midlife cardiorespiratory fitness with later life carotid atherosclerosis: Cooper Center Longitudinal Study

Background and aimsWhile numerous cross-sectional studies have demonstrated an inverse relationship between cardiorespiratory fitness (CRF) and carotid atherosclerosis in middle age, much less is known about the association of midlife CRF with carotid atherosclerosis in later life. MethodsWe studied 1094 participants, free of cardiovascular disease, who completed a maximal exercise test (GXT) for an objective measure of CRF between ages 40 and 59 and carotid ultrasound after the age of 59, with at least five years between studies. Carotid intima media thickness was measured. Assessments were also made regarding the presence of plaque and percent stenosis in four regions: common carotid, bulb, internal carotid and external carotid arteries. Multivariable logistic regression models were constructed to estimate the association of CRF with carotid artery disease. ResultsAt the time of GXT and carotid scan, participants were aged 50.7 ± 5.7 years and 69.3 ± 6.4 years, respectively. Almost half of participants had high midlife CRF (48.6%); 41.3% and 10.1% had moderate and low CRF, respectively. Over a mean follow-up period of 18.6 ± 8.5 years, the odds of having carotid artery disease in later life in the high CRF group was 0.50 (95% CI: 0.29–0.87) compared with the low CRF group. Each 1 MET increase in CRF was associated with 10% lower odds of having carotid artery disease (OR = 0.89, 95% CI: 0.80–0.98). ConclusionsMidlife CRF was inversely associated with carotid artery disease measured almost two decades later. This may represent a mechanistic link between high midlife CRF and reduced risk of stroke in later life.

Concurrent Relationship of Objectively Measured Physical Activity and Cardiorespiratory Fitness on Two Different Measures of Obesity in U.S. Adults

Background: Few population-based studies have examined the relationship of both physical activity (PA) and cardiorespiratory fitness (CRF) on the growing health problem of obesity. The purpose of this study was to examine the concurrent relationship of PA and CRF on two different measures of obesity. Methods: This study used data from adults 20-49 years of age participating in the 2003-2004 National Health and Nutrition Examination Survey (NHANES). Moderate-to-vigorous PA (MVPA, min/day) was objectively determined by use of accelerometer and participants were categorized into low or high groups using the median. CRF (ml/kg/min) was assessed using a submaximal treadmill test and measures were categorized into low or high values by applying age- and sex-specific standards. Using body mass index (BMI), participants were categorized as obese if their values were 30 kg/m2 or greater. Using waist circumference (WC), participants were categorized as obese if their values were greater than 88 (females) or 102 cm (males). Linear regression was used to test for mean CRF differences in study variables. Logistic regression was used to model the relationship between MVPA, CRF and obesity. Results: Participants in the high CRF group had significantly (psConclusion: Results from this study indicate that PA is only related to obesity when CRF is low. Furthermore, high CRF may protect less physically active adults from both overall and abdominal obesity.

Cardiorespiratory Fitness and All-Cause Mortality in Men With Emotional Distress

ObjectiveMental health and emotional disorders are often associated with higher mortality risk. Whether higher cardiorespiratory fitness (CRF) reduces the risk for all-cause mortality in individuals with emotional distress is not well known. Patients and MethodsParticipants were 5240 men (mean age 46.5±9.5 years) with emotional distress (including depression, anxiety, thoughts of suicide, or a history of psychiatric or psychological counseling) who completed an extensive medical examination between 1987 and 2002, and were followed for all-cause mortality through December 31, 2003. Cardiorespiratory fitness was quantified as maximal treadmill exercise test duration and was grouped for analysis as low, moderate, and high. Cox proportional hazards regression was used to calculate hazard ratios (HRs) and 95% CIs. ResultsDuring a median of 8.7 years (range, 1.0-16.9 years) and 46,217 person-years of follow-up, there were 128 deaths from any cause. Age- and examination year–adjusted all-cause mortality rates per 10,000 person-years according to low, moderate, and high CRF groups were 64.7 (95% CI, 44.9-89.3), 28.0 (95% CI, 23.8-31.5), and 19.6 (95% CI, 17.1-21.6) (trend P<.001) in men who reported any emotional distress. Overall, the multivariable-adjusted HRs and 95% CIs across incremental CRF categories were 1.00 (referent), 0.54 (0.32-0.90), and 0.47 (0.26-0.85), linear trend P =.03. ConclusionAmong men with emotional distress, higher CRF is associated with lower risk of dying, independent of other clinical mortality predictors. Our findings underscore the importance of promoting physical activity to maintain a healthful level of CRF in individuals with emotional distress.

Carotid 2D Strain Imaging Reveals Enhanced Rate Of Arterial Wall Deformation Following Exercise In High-fit Young Males

PURPOSE: The purpose of this study was to compare common carotid artery (CCA) stiffness at rest and immediately following brief aerobic exercise between young males of moderate and high cardiorespiratory fitness (CRF). METHODS: Accordingly, heart rate (HR), blood pressure (BP), arterial diameter, conventional parameters of arterial stiffness (Petersons’ elastic modulus [Ep], β1 stiffness index) and novel two-dimensional (2D) strain imaging indices (global circumferential strain, strain rate and β2 stiffness index) were assessed in the CCA pre and immediately post 5-min of aerobic exercise (40% peak exercise capacity) in twenty-two young healthy males (age: 21 ± 2 years). Moderate and high CRF groups demonstrated mean V†o2 peak data of 49 ± 8 and 66 ± 6 mL kg-1min-1, respectively (P <.001). RESULTS: Heart rate, systolic BP, pulse pressure, mean arterial pressure, arterial diameter, Ep, β1 and β2 stiffness indices were not different between fitness groups at rest or immediately following exercise (all P > .05). However, whilst there was a similar increase in CCA wall deformation as indicated by global circumferential strain following exercise (pre vs. post, moderate: 9.12 ± 2.6% vs. 9.36 ± 2.4%; high: 10.19 ± 2.9% vs. 11.34 ± 2.9%, both P > .05), CCA wall deformation was significantly faster in the high-fit group only, as reflected by increased systolic circumferential strain rate (moderate: 1.09 ± 0.3 vs. 1.17 ± 0.2 1/s, P > .05; high: 1.14 ± 0.2 vs. 1.35 ± 0.3 1/s, P = .049). CONCLUSION: Using novel 2D strain imaging, this study shows that young high-fit individuals may exhibit different arterial wall dynamics compared to their lower-fit counterparts following a short bout of aerobic exercise. The increase in global circumferential strain rate following exercise in high-fit individuals may reflect a greater ability to buffer the significant rise in pulse-pressure and blood flow that occurs in response to exercise.