Effect of physical activity on age-related changes in cardiac function and performance in women

Impact of surgical and non-surgical weight loss on echocardiographic and strain parameters in Asian patients

Surgical weight loss (SWL) improves myocardial mechanics as measured by speckle-tracking imaging. However non-surgical versus SWL and the subsequent impact on myocardial function in overweight Asian subjects has not been evaluated. 66 patients underwent a 16-week lifestyle intervention (LSI) programme consisting of dietary interventions and exercise prescription. Echocardiography with speckle tracking was performed at baseline and post-intervention. This group was compared against a group of 12 subjects who had undergone bariatric surgery and a control group of 10 lean Asian subjects. A generalised structural equation model (gSEM) was constructed to ascertain the effect of modality of weight loss on strain parameters, adjusting for BMI. Participants attained significant weight loss after LSI (28.2 ± 2.66 kg/m2 vs. 25.8 ± 2.84 kg/m2, p = 0.001). This was associated with a non-significant trend towards improvement in strain parameters. SWL participants had significant improvement in the left ventricular global longitudinal strain (- 20.52 ± 3.34 vs. - 16.68 ± 4.15, p < 0.01) and left atrium reservoir strain (44.32 ± 14.23 vs. 34.3 ± 19.31, p = 0.02). Lean subjects had significantly higher strain parameters than overweight subjects. The gSEM model demonstrated surgical modality of weight loss as an independent predictor of improvement in strain parameters. Significant improvement in echocardiographic parameters were documented in patients who underwent bariatric surgery.

A comparison of continuous, interval, and accumulated workouts with equalized exercise volume: excess post-exercise oxygen consumption in women

BACKGROUND

Despite the well-known health benefits of exercise, women's participation in exercise is low worldwide. As women are at risk of developing various chronic diseases as they age, suggesting effective exercise methods that can maximize energy consumption is needed to prevent such conditions. Excess post-exercise oxygen consumption (EPOC) can maximize energy consumption. In this crossover, randomized controlled trial, we aimed to compare the EPOC for different exercise modalities including continuous exercise (CE), interval exercise (IE), and accumulated exercise (AE) that spent the homogenized energy expenditure during exercise in healthy women.

METHODS

Forty-four participants (age, 36.09 ± 11.73 years) were recruited and randomly allocated to three groups. The intensity of each modality was set as follows: CE was performed for 30 min at 60% peak oxygen uptake (VO2peak). IE was performed once for 2 min at 80% VO2peak, followed by 3 min at 80% VO2peak, and 1 min at 40% VO2peak, for a total of six times over 26 min. AE was performed for 10 min with a 60% VO2peak and was measured thrice a day.

RESULTS

During exercise, energy metabolism was higher for IE and CE than that for AE. However, this was reversed for AE during EPOC. Consequently, the greatest energy metabolism was shown for AE during total time (exercise and EPOC).

CONCLUSIONS

By encouraging regular exercises, AE can help maintain and improve body composition by increasing compliance with exercise participation, given its short exercise times, and by efficiently increasing energy consumption through the accumulation of EPOC.

TRIAL REGISTRATION

Clinical number (KCT0007298), 18/05/2022, Institutional Review Board of Konkuk University (7001355-202201-E-160).

Care of The Older Fighter: Position Statement of the Association of Ringside Physicians

Older Fighters are defined as combat sports athletes older than 35 years, based on heightened medical risks and historical classification. Age-related changes to the neurological, cardiopulmonary, endocrinological, thermoregulatory, osmoregulatory, and musculoskeletal systems increase these athletes' risks for injury and may prolong their recovery. These age-related risks warrant special considerations for competition, licensure, prefight medical clearance, in-fight supervision, post-fight examination, and counseling regarding training practices and retirement from combat sports. Neurological considerations include increased risk of intracranial lesions, intracranial hemorrhage, and sequelae from traumatic brain injury (TBI), warranting more comprehensive neurological evaluation and neuroimaging. Increased risk of myocardial ischemia and infarction warrant careful assessment of cardiac risk factors and scrutiny of cardiovascular fitness. Older fighters may take longer time to recover from musculoskeletal injury; post-injury clearance should be individualized.

Integrated Functions of Cardiac Energetics, Mechanics, and Purine Nucleotide Metabolism

Purine nucleotides play central roles in energy metabolism in the heart. Most fundamentally, the free energy of hydrolysis of the adenine nucleotide adenosine triphosphate (ATP) provides the thermodynamic driving force for numerous cellular processes including the actin-myosin crossbridge cycle. Perturbations to ATP supply and/or demand in the myocardium lead to changes in the homeostatic balance between purine nucleotide synthesis, degradation, and salvage, potentially affecting myocardial energetics and, consequently, myocardial mechanics. Indeed, both acute myocardial ischemia and decompensatory remodeling of the myocardium in heart failure are associated with depletion of myocardial adenine nucleotides and with impaired myocardial mechanical function. Yet there remain gaps in the understanding of mechanistic links between adenine nucleotide degradation and contractile dysfunction in heart disease. The scope of this article is to: (i) review current knowledge of the pathways of purine nucleotide depletion and salvage in acute ischemia and in chronic heart disease; (ii) review hypothesized mechanisms linking myocardial mechanics and energetics with myocardial adenine nucleotide regulation; and (iii) highlight potential targets for treating myocardial metabolic and mechanical dysfunction associated with these pathways. It is hypothesized that an imbalance in the degradation, salvage, and synthesis of adenine nucleotides leads to a net loss of adenine nucleotides in both acute ischemia and under chronic high-demand conditions associated with the development of heart failure. This reduction in adenine nucleotide levels results in reduced myocardial ATP and increased myocardial inorganic phosphate. Both of these changes have the potential to directly impact tension development and mechanical work at the cellular level. © 2024 American Physiological Society. Compr Physiol 14:5345-5369, 2024.

Sex differences in frailty among older adults

By definition, aging is a natural, gradual and continuous process. On the other hand, frailty reflects the increase in vulnerability to stressors and shortens the time without disease (health span) while longevity refers to the length of life (lifespan). The average life expectancy has significantly increased during the last few decades. A longer lifespan has been accompanied by an increase in frailty and decreased independence in older adults, with major differences existing between men and women. For example, women tend to live longer than men but also experience higher rates of frailty and disability. Sex differences prevent optimization of lifestyle interventions and therapies to effectively prevent frailty. Sex differences in frailty and aging are rooted in a complex interplay between uncontrollable (genetic, epigenetic, physiological), and controllable factors (psychosocial and lifestyle factors). Thus, understanding the underlying causes of sex differences in frailty and aging is essential for developing personalized interventions to promote healthy aging and improve quality of life in older men and women. In this review, we have discussed the key contributors and knowledge gaps related to sex differences in aging and frailty.

Left Ventricular Diastolic Response to Isometric Handgrip Exercise in Physically Active and Sedentary Individuals

Aims: This study aims to investigate the diastolic left ventricular (LV) response to isometric handgrip exercise among healthy middle-aged men with high physical activity levels, versus matched sedentary individuals. Methods: Two groups of 10 men aged 41−51 years were studied. Men in the first group had high weekly self-reported physical activity levels (>3000 METs × min/week). In comparison, men in the second group reported low physical activity levels (<300 METs × min/week). An isometric handgrip exercise (IHE) stress echocardiography test was performed in all of them. Results: Both groups showed a similar and statistically significant increase in heart rate, systolic, diastolic, and mean arterial pressure following IHE. The group of active men under study did not show a statistically significant change in the ratio of early diastolic mitral valve inflow velocity to early diastolic lateral wall tissue velocity (E/e’ ratio) in response to IHE. Conversely, the inactive participants’ E/e’ ratio was higher at peak activity in the isometric handgrip exercise. Conclusions: Apparently, healthy middle-aged men with high levels of physical activity seem to have an improved lusitropic cardiac function compared to men with low levels of physical activity, as observed by the different diastolic LV responses induced by isometric handgrip exercise.

Caloric restriction-mimetics for the reduction of heart failure risk in aging heart: with consideration of gender-related differences

The literature is full of claims regarding the consumption of polyphenol or polyamine-rich foods that offer some protection from developing cardiovascular disease (CVD). This is achieved by preventing cardiac hypertrophy and protecting blood vessels through improving the function of endothelium. However, do these interventions work in the aged human hearts? Cardiac aging is accompanied by an increase in left ventricular hypertrophy, along with diastolic and systolic dysfunction. It also confers significant cardiovascular risks for both sexes. The incidence and prevalence of CVD increase sharply at an earlier age in men than women. Furthermore, the patterns of heart failure differ between sexes, as do the lifetime risk factors. Do caloric restriction (CR)-mimetics, rich in polyphenol or polyamine, delay or reverse cardiac aging equally in both men and women? This review will discuss three areas: (1) mechanisms underlying age-related cardiac remodeling; (2) gender-related differences and potential mechanisms underlying diminished cardiac response in older men and women; (3) we select a few polyphenol or polyamine rich compounds as the CR-mimetics, such as resveratrol, quercetin, curcumin, epigallocatechin gallate and spermidine, due to their capability to extend health-span and induce autophagy. We outline their abilities and issues on retarding aging in animal hearts and preventing CVD in humans. We discuss the confounding factors that should be considered for developing therapeutic strategies against cardiac aging in humans.

Re-evaluating methods reporting practices to improve reproducibility: an analysis of methodological rigor for the Langendorff whole-heart technique

In recent decades, the scientific community has seen an increased interest in rigor and reproducibility. In 2017, concerns of methodological thoroughness and reporting practices were implicated as significant barriers to reproducibility within the preclinical cardiovascular literature, particularly in studies employing animal research. The Langendorff, whole-heart technique has proven to be an invaluable research tool, being modified in a myriad of ways to probe questions across the spectrum of physio- and pathophysiologic function of the heart. As a result, significant variability in the application of the Langendorff technique exists. This literature review quantifies the different methods employed in the implementation of the Langendorff technique and provides brief examples of how individual parametric differences can impact the outcomes and interpretation of studies. From 2017-2020, significant variability of animal models, anesthesia, cannulation time, and perfusate composition, pH, and temperature demonstrate that the technique has diversified to meet new challenges and answer different scientific questions. The review also reveals which individual methods are most frequently reported, even if there is no explicit agreement upon which parameters should be reported. The analysis of methods related to the Langendorff technique suggests a framework for considering methodological approach when interpreting seemingly contradictory results, rather than concluding that results are irreproducible.

Effectiveness of a multicomponent exercise program to reverse pre-frailty in community-dwelling Chinese older adults: a randomised controlled trial

BACKGROUND

the Xiangya Hospital circuit training (X-CircuiT), was developed to reverse pre-frailty in Chinese older adults and determine potential mechanisms through which pre-frailty is reversed.

METHODS

this randomised controlled trial was performed at Xiangya Hospital, Changsha, China from September 2020 to May 2021. Forty-eight pre-frail older adults were enrolled. Participants were randomly assigned (1:1) to X-CircuiT (46 min/session, three supervised sessions/week for 3 months at a community health centre) or control (1-time advice on physical activity without supervised exercise). The primary outcome was the proportion of participants with pre-frailty after 3-month intervention. The secondary outcomes included absolute risk reduction (ARR), number needed to treat (NNT), and the changes in senior fitness, body composition and clinical measures.

RESULTS

among 48 participants (mean age, 72 years; women [65%]), 22 participants in the X-CircuiT (92%) and 21 participants in the control (88%) completed the study. After 3 months, the proportion of pre-frailty was significantly lower in the X-CircuiT group than the control (14% versus 95%, P < 0.001). The ARR and NNT were 82% [95% CI, 65-99] and 1 [1-2], respectively. X-CircuiT was associated with significant improvements in senior fitness indicators and body composition. No significant difference in blood chemistry, carotid ultrasound and echocardiography parameters was found between groups. No significant interaction was detected between sex, BMI, baseline peak oxygen consumption and study groups.

CONCLUSION

this study demonstrates that X-CircuiT could significantly reverse pre-frailty in Chinese older adults. The underlying mechanisms may involve X-CircuiT-induced improvements in body composition and senior fitness.The trial is registered at Chictr.org.cn. Number: ChiCTR2100048125.

Exercise, programmed cell death and exhaustion of cardiomyocyte proliferation in aging zebrafish

Exercise may ameliorate the eventual heart failure inherent in human aging. In this study, we use zebrafish to understand how aging and exercise affect cardiomyocyte turnover and myocardial remodelling. We show that cardiomyocyte proliferation remains constant throughout life but that onset of fibrosis is associated with a late increase in apoptosis. These findings correlate with decreases in voluntary swimming activity, critical swimming speed (Ucrit), and increases in biomarkers of cardiac insufficiency. The ability to respond to severe physiological stress is also impaired with age. Although young adult fish respond with robust cardiomyocyte proliferation in response to enforced swimming, this is dramatically impaired in older fish and served by a smaller proliferation-competent cardiomyocyte population. Finally, we show that these aging responses can be improved through increased activity throughout adulthood. However, despite improvement in Ucrit and the proliferative response to stress, the size of the proliferating cardiomyocyte population remained unchanged. The zebrafish heart models human aging and reveals the important trade-off between preserving cardiovascular fitness through exercise at the expense of accelerated fibrotic change.

Cardiac Energetics Before, During, and After Anthracycline-Based Chemotherapy in Breast Cancer Patients Using 31P Magnetic Resonance Spectroscopy: A Pilot Study

Purpose: To explore the utility of phosphorus magnetic resonance spectroscopy (³¹P MRS) in identifying anthracycline-induced cardiac toxicity in patients with breast cancer.

Methods: Twenty patients with newly diagnosed breast cancer receiving anthracycline-based chemotherapy had cardiac magnetic resonance assessment of left ventricular ejection fraction (LVEF) and ³¹P MRS to determine myocardial Phosphocreatine/Adenosine Triphosphate Ratio (PCr/ATP) at three time points: pre-, mid-, and end-chemotherapy. Plasma high sensitivity cardiac troponin-I (cTn-I) tests and electrocardiograms were also performed at these same time points.

Results: Phosphocreatine/Adenosine Triphosphate did not change significantly between pre- and mid-chemo (2.16 ± 0.46 vs. 2.00 ± 0.56, p = 0.80) and pre- and end-chemo (2.16 ± 0.46 vs. 2.17 ± 0.86, p = 0.99). Mean LVEF reduced significantly by 5.1% between pre- and end-chemo (61.4 ± 4.4 vs. 56.3 ± 8.1 %, p = 0.02). Change in PCr/ATP ratios from pre- to end-chemo correlated inversely with changes in LVEF over the same period (r = −0.65, p = 0.006). Plasma cTn-I increased progressively during chemotherapy from pre- to mid-chemo (1.35 ± 0.81 to 4.40 ± 2.64 ng/L; p = 0.01) and from mid- to end-chemo (4.40 ± 2.64 to 18.33 ± 13.23 ng/L; p = 0.001).

Conclusions: In this small cohort pilot study, we did not observe a clear change in mean PCr/ATP values during chemotherapy despite evidence of increased plasma cardiac biomarkers and reduced LVEF. Future similar studies should be adequately powered to take account of patient drop-out and variable changes in PCr/ATP and could include T1 and T2 mapping.

What are the Physiological Benefits of Increased Daily Number of Steps in Middle-Aged Women?

BACKGROUND

Physical activity plays an important role in the prevention of cardio-metabolic diseases. The present study evaluated the effect of habitual physical activity on body composition, peak oxygen consumption, cardiac and metabolic function.

METHODS

This was a retrospective study. Data was collected between February 2014 and November 2015. Thirty-six healthy women (age 50±16 years) were stratified according to daily number of steps into low- (<7500 steps/day, n=17) or high-active group (>12500 steps/day, n=19). All participants underwent body composition assessment, oral glucose tolerance test and non-invasive gas-exchange and haemodynamic (bioreactance) measurements at rest and in response to maximal graded cardiopulmonary exercise test.

RESULTS

The high active group averaged 16280±3205 steps/day and the low active group averaged 6285±943 steps/day (difference p=0.00). High-active women (vs. low active) demonstrated significantly lower body weight (62.1±12.3 vs. 71.2±9.1 kg, p=0.02), body fat (27.2±9.1 vs 37.7±6.4 %, p=0.00), but increased lean body mass (72.8±9.1 vs. 62.3±6.4 %, p=0.00). Peak oxygen consumption was significantly higher in high- versus low active women (2.0±0.5 vs. 1.5±0.2 l/min, p=0.00). There were no significant differences between the groups in fasting- and 2-hour glucose levels (4.9±0.6 vs. 4.8±0.5, p=0.45 and 4.8±1.3 vs. 5.5±1.4 mmol/L, p=0.16) haemodynamic measures of cardiac function including cardiac power output, cardiac output, stroke volume and arterial blood pressure at rest and in response to exercise stress test (p>0.05).

CONCLUSIONS

Increased levels of habitual physical activity improve body composition and peak oxygen consumption but appears to have limited effect cardio-metabolic function in middle-aged women.

Non-invasive investigation of myocardial energetics in cardiac disease using 31P magnetic resonance spectroscopy

Cardiac metabolism and function are intrinsically linked. High-energy phosphates occupy a central and obligate position in cardiac metabolism, coupling oxygen and substrate fuel delivery to the myocardium with external work. This insight underlies the widespread clinical use of ischaemia testing. However, other deficits in high-energy phosphate metabolism (not secondary to supply-demand mismatch of oxygen and substrate fuels) may also be documented, and are of particular interest when found in the context of structural heart disease. This review introduces the scope of deficits in high-energy phosphate metabolism that may be observed in the myocardium, how to assess for them, and how they might be interpreted.

Cardiac Metabolic Limitations Contribute to Diminished Performance of the Heart in Aging

Changes in the myocardial energetics associated with aging-reductions in creatine phosphate/ATP ratio, total creatine, and ATP-mirror changes observed in failing hearts compared to healthy controls. Similarly, both aging and heart failure are associated with significant reductions in cardiac performance and maximal left ventricular cardiac power output compared with young healthy individuals. Based on these observations, we hypothesize that reductions in the concentrations of cytoplasmic adenine nucleotide, creatine, and phosphate pools that occur with aging impair the myocardial capacity to synthesize ATP at physiological free energy levels and that the resulting changes to myocardial energetic status impair the mechanical pumping ability of the heart. The purpose of this study is to test these hypotheses using an age-structured population model for myocardial metabolism in the adult female population and to determine the potential impact of reductions in key myocardial metabolite pools in causing metabolic/energetic and cardiac mechanical dysfunction associated with aging. To test these hypotheses, we developed a population model for myocardial energetics to predict myocardial ATP, ADP, creatine phosphate, creatine, and inorganic phosphate concentrations as functions of cardiac work and age in the adult female population. Model predictions support our hypotheses and are consistent with previous experimental observations. The major findings provide a novel, to our knowledge, theoretical and computational framework for further probing complex relationships between the energetics and performance of the heart with aging.

Cardiac function is not associated with glucose control in older women

The present study evaluated the effect of age on glucose tolerance and cardiac function and assessed the relationship between metabolic control and cardiac function and performance. Thirty-four healthy women aged 40 to 81 years were divided into two age groups: younger (≤50 years of age, N = 19) and older (≥60 years of age, N = 15). Participants performed an oral glucose tolerance test and a graded cardiopulmonary exercise test with non-invasive haemodynamic measurements. Compared to younger, older women demonstrated significantly higher 2-hour glucose (4.67 ± 1.01 vs 6.08 ± 1.54 mmol/l, P < 0.01), but lower peak exercise O₂ consumption (1.96 ± 0.44 vs 1.38 ± 0.26 l/min, P < 0.01) and cardiac power output (4.06 ± 0.76 vs 3.35 ± 0.73 W, P = 0.01). When data from all study participants were combined, there was a significant negative relationship between 2-hour glucose and peak cardiac power (r = -0.39, P = 0.02), and peak O₂ consumption (r = -0.40, P = 0.02). The strength of these relationships was affected by age, with moderate negative relationship identified between 2-hour glucose and peak cardiac power output in younger compared to older participants (r = -0.38, P = 0.11 vs. r = -0.09, P = 0.75). Metabolic control and cardiac function decline with age. The lack of relationship between glucose control and cardiac power may suggest that metabolic control does not influence cardiac function and performance in older women.

Adiposity predicts low cardiorespiratory fitness in individuals with metabolic diseases

Cardiorespiratory fitness (CRF) is impaired in those with metabolic diseases and strongly predicts mortality. We found that adiposity, not glycaemic control or disease type, is the strongest predictor of low CRF in those with metabolic diseases. We discuss how adiposity and metabolic health may relate to outcomes in obesity.

Age-related decline in cardiac autonomic function is not attenuated with increased physical activity

Age and physical inactivity are important risk factors for cardiovascular mortality. Heart rate response to exercise (HRRE) and heart rate recovery (HRR), measures of cardiac autonomic function, are strong predictors of mortality. The present study defined the effect of age and physical activity on HRRE and HRR. Healthy women (N=72) grouped according to age (young, 20-30 years; middle, 40-50 years; and older, 65-81 years) and daily physical activity (low active <7500, high active >12,500 steps/day) performed a maximal cardiopulmonary exercise test. The HRRE was defined as an increase in heart rate from rest to 1, 3 and 5 minutes of exercise and at 1/3 of total exercise time, and HRR as the difference in heart rate between peak exercise and 1, 2, and 3 minutes later. Age was associated with a significant decline in HRRE at 1 min and 1/3 of exercise time (r= − 0.27, p=0.04, and r=−0.39, p=0.02) and HRR at 2 min and 3 min (r=−0.35, p=0.01, and r=−0.31, p=0.02). There was no significant difference in HRRE and HRR between high and low-active middle-age and older women (p>0.05). Increased level of habitual physical activity level appears to have a limited effect on age-related decline in cardiac autonomic function in women.

Impact of age on the association between cardiac high-energy phosphate metabolism and cardiac power in women

OBJECTIVE

Diminished cardiac high-energy phosphate metabolism (phosphocreatine-to-ATP (PCr:ATP) ratio) and cardiac power with age may play an important roles in development of cardiac dysfunction and heart failure. The study defines the impact of age on PCr:ATP ratio and cardiac power and their relationship.

METHODS

Thirty-five healthy women (young≤50 years, n=20; and old≥60 years, n=15) underwent cardiac MRI with 31P spectroscopy to assess PCr:ATP ratio and performed maximal graded cardiopulmonary exercise testing with simultaneous gas-exchange and central haemodynamic measurements. Peak cardiac power output, as the best measure of pumping capability and performance of the heart, was calculated as the product of peak exercise cardiac output and mean arterial blood pressure.

RESULTS

PCr:ATP ratio was significantly lower in old compared with young age group (1.92±0.48 vs 2.29±0.55, p=0.03), as were peak cardiac power output (3.35±0.73 vs 4.14±0.81W, p=0.01), diastolic function (ie, early-to-late diastolic filling ratio, 1.33±0.54 vs 3.07±1.84, p<0.01) and peak exercise oxygen consumption (1382.9±255.0 vs 1940.3±434.4 mL/min, p<0.01). Further analysis revealed that PCr:ATP ratio shows a significant positive relationship with early-to-late diastolic filling ratio (r=0.46, p=0.02), peak cardiac power output (r=0.44, p=0.02) and peak oxygen consumption (r=0.51, p=0.01).

CONCLUSIONS

High-energy phosphate metabolism and peak power of the heart decline with age. Significant positive relationship between PCr:ATP ratio, early-to-late diastolic filling ratio and peak cardiac power output suggests that cardiac high-energy phosphate metabolism may be an important determinant of cardiac function and performance.

Association Between Sedentary Lifestyle and Diastolic Dysfunction Among Outpatients With Normal Left Ventricular Systolic Function Presenting to a Tertiary Referral Center in the Middle East

BACKGROUND

Sedentary lifestyle has become prevalent in our community. Recent data showed controversy on the effect of regular exercise on left ventricular compliance and myocardial relaxation.

HYPOTHESIS

We sought to assess whether physical inactivity is an independent predictor of diastolic dysfunction in or community, after adjustment for several covariates.

METHODS

Consecutive outpatients presenting to the echocardiography laboratory between July 2013 and June 2014 were prospectively enrolled. Clinical variables were collected prospectively at enrollment. Patients were considered physically active if they exercised regularly ≥3× a week, ≥30 minutes each time. The primary endpoint was presence of diastolic dysfunction.

RESULTS

The final cohort included 1356 patients (mean age [SD] 52.9 [17.4] years, 51.3% female). Compared with physically active patients, the 1009 (74.4%) physically inactive patients were older, more often female, and had more comorbidities and worse diastolic function (51.3% vs 38.3%; P < 0.001). On univariate analysis, physical inactivity was associated with 70% increased odds of having diastolic dysfunction (odds ratio: 1.70, 95% confidence interval: 1.32-2.18, P < 0.001). There was significant interaction between physical activity and left ventricular mass index (LVMI; P = 0.026). On multivariate analysis, patients who were physically inactive and had LVMI ≥ median had significantly higher odds of having diastolic dysfunction (odds ratio: 2.82, 95% confidence interval: 1.58-5.05, P < 0.001).

CONCLUSIONS

In a large, prospectively enrolled cohort from a single tertiary center in the Middle East, physically inactive patients with increased LVMI had 2- to 3-fold increased odds of having diastolic dysfunction after multivariate adjustment.

The Effect of Short and Long Term Endurance Training on Systemic, and Muscle and Prefrontal Cortex Tissue Oxygen Utilisation in 40 - 60 Year Old Women

Purpose

Aerobic endurance training (ET) increases systemic and peripheral oxygen utilisation over time, the adaptation pattern not being linear. However, the timing and mechanisms of changes in oxygen utilisation, associated with training beyond one year are not known. This study tested the hypothesis that in women aged 40–60 years performing the same current training load; systemic O₂ utilisation (VO₂) and tissue deoxyhaemoglobin (HHb) in the Vastus Lateralis (VL) and Gastrocnemius (GAST) would be higher in long term trained (LTT; > 5 yr) compared to a short term trained (STT; 6–24 months) participants during ramp incremental (RI) cycling, but similar during square-wave constant load (SWCL) cycling performed at the same relative intensity (below ventilatory turn point [VTP]); and that pre-frontal cortex (PFC) HHb would be similar between participant groups in both exercise conditions.

Methods

Thirteen STT and 13 LTT participants performed RI and SWCL conditions on separate days. VO₂, and VL, GAST, and PFC HHb were measured simultaneously.

Results

VO_2peak was higher in LTT compared to STT, and VO₂ was higher in LTT at each relative intensities of 25%, 80% and 90% of VTP in SWCL. HHb in the VL was significantly higher in LTT compared to STT at peak exercise (4.54 ± 3.82 vs 1.55 ± 2.33 μM), and at 25% (0.99 ± 1.43 vs 0.04 ± 0.96 μM), 80% (3.19 ± 2.93 vs 1.14 ± 1.82 μM) and 90% (4.62 ± 3.12 vs 2.07 ± 2.49 μM) of VTP in SWCL.

Conclusions

The additional (12.9 ± 9.3) years of ET in LTT, resulted in higher VO₂, and HHb in the VL at peak exercise, and sub—VTP exercise. These results indicate that in women 40–60 years old, systemic and muscle O₂ utilisation continues to improve with ET beyond two years.

Impact of aging on mitochondrial function in cardiac and skeletal muscle

Both skeletal muscle and cardiac muscle are subject to marked structural and functional impairment with aging and these changes contribute to the reduced capacity for exercise as we age. Since mitochondria are involved in multiple aspects of cellular homeostasis including energetics, reactive oxygen species signaling, and regulation of intrinsic apoptotic pathways, defects in this organelle are frequently implicated in the deterioration of skeletal and cardiac muscle with aging. On this basis, the purpose of this review is to evaluate the evidence that aging causes dysfunction in mitochondria in striated muscle with a view towards drawing conclusions about the potential of these changes to contribute to the deterioration seen in striated muscle with aging. As will be shown, impairment in respiration and reactive oxygen species emission with aging are highly variable between studies and seem to be largely a consequence of physical inactivity. On the other hand, both skeletal and cardiac muscle mitochondria are more susceptible to permeability transition and this seems a likely cause of the increased recruitment of mitochondrial-mediated pathways of apoptosis seen in striated muscle. The review concludes by examining the role of degeneration of mitochondrial DNA versus impaired mitochondrial quality control mechanisms in the accumulation of mitochondria that are sensitized to permeability transition, whereby the latter mechanism is favored as the most likely cause.

The effect of age on the relationship between cardiac and vascular function

Age-related changes in cardiac and vascular function are associated with increased risk of cardiovascular mortality and morbidity. The aim of the present study was to define the effect of age on the relationship between cardiac and vascular function. Haemodynamic and gas exchange measurements were performed at rest and peak exercise in healthy individuals. Augmentation index was measured at rest. Cardiac power output, a measure of overall cardiac function, was calculated as the product of cardiac output and mean arterial blood pressure. Augmentation index was significantly higher in older than younger participants (27.7 ± 10.1 vs. 2.5 ± 10.1%, P<0.01). Older people demonstrated significantly higher stroke volume and mean arterial blood pressure (P<0.05), but lower heart rate (145 ± 13 vs. 172 ± 10 beats/min, P<0.01) and peak oxygen consumption (22.5 ± 5.2 vs. 41.2 ± 8.4 ml/kg/min, P<0.01). There was a significant negative relationship between augmentation index and peak exercise cardiac power output (r=-0.73, P=0.02) and cardiac output (r=-0.69, P=0.03) in older participants. Older people maintain maximal cardiac function due to increased stroke volume. Vascular function is a strong predictor of overall cardiac function in older but in not younger people.

Clinical implications of aging

Figure summarizes the major changes of aging and some key ways these changes affect pages. Though many changes occur with aging, under normal or resting conditions, there is usually very little functionally that is diminished solely on the basis of aging. The net effects are reductions in reserve capacity and placing geriatric patients at higher risk for adverse consequences related to medications and diseases. Interactions between lifestyle factors, such as exercise, diet, and environmental exposures, have a large impact on aging and lead to great individual variability. The interplay between these environmental factors, aging, and development of chronic diseases multiply the amount of variation seen as individual's age.