Republished: Basic science behind the cardiovascular benefits of exercise

Lifestyle and Cardiac Structure and Function in Healthy Midlife Population

The association between lifestyle and cardiac structure and function measures, such as global longitudinal strain and diastolic function in a healthy midlife general population, is not well known. A subpopulation of the Northern Finland Birth Cohort 1966 took part in follow-up, including echocardiography (n = 1,155) at the age of 46. All antihypertensive medication users (n = 164), patients with diabetes (n = 70), subjects with any cardiac diseases (n = 24), and subjects with echocardiography abnormalities (n = 21) were excluded. Moderate to vigorous physical activity (MVPA) was recorded with a wrist-worn accelerometer over 14 days and categorized into high, moderate, and low MVPA groups. Similarly, alcohol consumption was categorized as low, moderate, and high-dose users of alcohol and smoking as nonsmokers, former, and current smokers. The total number of healthy subjects included in the study was 715 (44% males). Left ventricular mass index and left atrial end-systolic volume index were significantly higher in the high MVPA group compared with the low MVPA group (adjusted main effect p = 0.002 and p <0.001, respectively). Cardiac function did not differ among the physical activity groups. High alcohol consumption was associated with impaired global longitudinal strain and diastolic function (adjusted main effect p = 0.002 and p = 0.004, respectively) but not with any cardiac structure variables. Smoking was not associated with cardiac structure or function. In healthy middle-aged adults, MVPA was independently associated with structural changes in the heart but not with cardiac function. High alcohol consumption was associated with impaired modern cardiac function measures but not with cardiac structure.

Hallmarks of exercised heart

The benefits of exercise in humans on the heart have been well recognized for many years. Long-term endurance exercise training can induce physiologic cardiac hypertrophy with normal or enhanced heart function, and provide protective benefits in preventing heart failure. The heart-specific responses that occur during exercise are complex and highly variable. This review mainly focuses on the current understanding of the structural and functional cardiac adaptations to exercise as well as molecular pathways and signaling proteins responsible for these changes. Here, we summarize eight tentative hallmarks that represent common denominators of the exercised heart. These hallmarks are: cardiomyocyte growth, cardiomyocyte fate reprogramming, angiogenesis and lymphangiogenesis, mitochondrial remodeling, epigenetic alteration, enhanced endothelial function, quiescent cardiac fibroblast, and improved cardiac metabolism. A major challenge is to explore the underlying molecular mechanisms for cardio-protective effects of exercise, and to identify therapeutic targets for heart diseases.

Estimated Artificial Neural Network Modeling of Maximal Oxygen Uptake Based on Multistage 10-m Shuttle Run Test in Healthy Adults

We aimed to develop an artificial neural network (ANN) model to estimate the maximal oxygen uptake (VO₂max) based on a multistage 10 m shuttle run test (SRT) in healthy adults. For ANN-based VO₂max estimation, 118 healthy Korean adults (59 men and 59 women) in their twenties and fifties (38.3 ± 11.8 years, men aged 37.8 ± 12.1 years, and women aged 38.8 ± 11.6 years) participated in this study; data included age, sex, blood pressure (systolic blood pressure (SBP), diastolic blood pressure (DBP)), waist circumference, hip circumference, waist-to-hip ratio (WHR), body composition (weight, height, body mass index (BMI), percent skeletal muscle, and percent body), 10 m SRT parameters (number of round trips and final speed), and VO₂max by graded exercise test (GXT) using a treadmill. The best estimation results (R² = 0.8206, adjusted R² = 0.7010, root mean square error; RMSE = 3.1301) were obtained in case 3 (using age, sex, height, weight, BMI, waist circumference, hip circumference, WHR, SBP, DBP, number of round trips in 10 m SRT, and final speed in 10 m SRT), while the worst results (R² = 0.7765, adjusted R² = 0.7206, RMSE = 3.494) were obtained for case 1 (using age, sex, height, weight, BMI, number of round trips in 10 m SRT, and final speed in 10 m SRT). The estimation results of case 2 (using age, sex, height, weight, BMI, waist circumference, hip circumference, WHR, number of round trips in 10 m SRT, and final speed in 10 m SRT) were lower (R² = 0.7909, adjusted R² = 0.7072, RMSE = 3.3798) than those of case 3 and higher than those of case 1. However, all cases showed high performance (R²) in the estimation results. This brief report developed an ANN-based estimation model to predict the VO₂max of healthy adults, and the model’s performance was confirmed to be excellent.

Change in Submaximal Cardiorespiratory Fitness and All-Cause Mortality

OBJECTIVE

To evaluate the relationship between change in submaximal cardiorespiratory fitness (sCRF) and all-cause mortality risk in adult men and women.

PATIENTS AND METHODS

A prospective study with at least 2 clinical visits (mean follow-up time, 4.2±3.0 years) between April 1974 and January 2002 was conducted to assess the relationship between change in sCRF and mortality risk during follow-up. Participants were 6106 men and women. Submaximal CRF was determined using the heart rate obtained at the 5-minute mark of a graded maximal treadmill test used to determine maximal CRF (mCRF). Change in sCRF from baseline to follow-up was categorized into 3 groups: increased fitness (decreased heart rate, <-4.0 beats/min), stable fitness (heart rate, -4.0 to 3.0 beats/min), and decreased fitness (increased heart rate, >3.0 beats/min).

RESULTS

The mean change in sCRF at follow-up for all 6106 study participants was -0.5±10.0 beats/min, and the mean change in mCRF was -0.3±1.4 metabolic equivalents. Change in sCRF was related to change in mCRF, though the variance explained was small (R²=0.21; P<.001). The hazard ratios (95% CIs) for all-cause mortality were 0.60 (0.38-0.96) for stable and 0.59 (0.35-1.00) for increased sCRF compared with decreased sCRF after adjusting for age, change in weight, and other common risk factors for premature mortality. The hazard ratios for changes in sCRF and mCRF were not significant after adjusting for changes in mCRF (P=.29) and sCRF (P=.60), respectively.

CONCLUSION

A simple 5-minute submaximal test of CRF identified that adults who maintained or improved sCRF were less likely to die from all causes during follow-up than were adults whose sCRF decreased.

Sex-related differences in reactivity of cerebral arterioles during moderate exercise training

OBJECTIVE

Our goals were to determine the influence of sex on reactivity of cerebral arterioles and whether MExT could influence sex-related differences in reactivity of cerebral arterioles.

MATERIALS AND METHODS

Responses of cerebral arterioles were measured in Sed and MExT adult male and female Sprague-Dawley rats to eNOS-dependent (ADP), nNOS-dependent (NMDA), and NOS-independent (nitroglycerin) agonists before and following L-NMMA. In addition, protein expression for eNOS and nNOS was determined.

RESULTS

NOS-dependent vasodilation was enhanced in Sed and MExT female rats compared to their male counterparts. L-NMMA produced a greater decrease in baseline diameter of arterioles in females compared to males, and produced less inhibition of NOS-dependent vasodilation in females. Expression of eNOS protein was significantly increased in Sed female when compared to Sed male rats; nNOS protein was similar in Sed males and females, but increased in MExT females.

CONCLUSIONS

The findings from this study indicate that while NOS-dependent vascular reactivity is increased in females, MExT does not alter vasodilation in males or females. These studies provide insights into the influence of sex and MExT on the cerebral microcirculation and may have implications regarding mechanisms that protect the brain in females compared to males.

Evaluating the Effectiveness of Physical Exercise Interventions in Persons Living With HIV: Overview of Systematic Reviews

Physical exercise (PE) has not been well studied in persons living with HIV (PLHIV). We conducted an overview of systematic reviews to assess the effectiveness of PE and to determine the most appropriate PE regimen for PLHIV. We used the CDC's Prevention Research Synthesis Project's database and manual searches to identify systematic reviews published between 1996 and 2013. We qualitatively synthesized the findings from five reviews to assess the effectiveness of PE and conducted meta-analyses on CD4 counts to identify the best PE regimen. PE is associated with reduced adiposity and depression, but was not associated with a decrease in HIV viral load. CD4 counts were improved by interventions with interval aerobic or 41-50 minutes of exercise three times per week compared with other modes and duration of exercise. PE appears to benefit PLHIV, but more research is needed to help develop appropriate PE strategies specifically for PLHIV.

Effectiveness of functional training on cardiorespiratory parameters: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Functional training is a new training vision that was prepared from the gesture imitation of daily activities. Although your use has become popular in clinical practice, the influence of the several cardiorespiratory adjustments performed during the functional training in different populations and conditions is unknown. So, the aim of this systematic review was to gather information in the literature regarding the influence of functional training on cardiorespiratory parameters.

METHODS

We conducted search strategies on MEDLINE, PEDro, EMBASE, SportDiscus and Cochrane to identify randomized controlled trials investigating the effects of functional training on cardiorespiratory parameters. Methodological quality of the included studies was assessed using the PEDro scale. Grading of Recommendations Assessment, Development and Evaluation (GRADE) summarized the evidence.

RESULTS

Five original studies were included. Effects favoured functional training on oxygen consumption (VO₂ ) at intermediate-term follow-up: weighted mean difference -1·0 (95% CI: 5·4-3·3), P = 0·642, and a small and not clinically important effect observed on VO₂ favouring control at intermediate-term follow-up (i.e. mean difference of 1·30 (95% CI 1·07-1·53), P<0·001).

CONCLUSION

According to the GRADE system, there is very low quality evidence that functional training is better than other interventions to improve cardiovascular parameters. This result encourages new searches about the theme.