The effect of lifelong exercise dose on cardiovascular function during exercise

Effects of aging and lifelong aerobic exercise on basal and exercise-induced inflammation

Age-associated chronic basal inflammation compromises muscle mass and adaptability, but exercise training may exert an anti-inflammatory effect. This investigation assessed basal and exercise-induced inflammation in three cohorts of men: young exercisers [YE; n = 10 men; 25 ± 1 yr; maximal oxygen consumption (V̇o2max), 53 ± 3 mL·kg-1·min-1; quadriceps area, 78 ± 3 cm2; means ± SE], old healthy nonexercisers (OH; n = 10; 75 ± 1 yr; V̇o2max, 22 ± 1 mL·kg-1·min-1; quadriceps area, 56 ± 3 cm2), and lifelong exercisers with an aerobic training history of 53 ± 1 yr (LLE; n = 21; 74 ± 1 yr; V̇o2max, 34 ± 1 mL·kg-1·min-1; quadriceps area, 67 ± 2 cm2). Resting serum IL-6, TNF-α, C-reactive protein, and IGF-1 levels were measured. Vastus lateralis muscle biopsies were obtained at rest (basal) and 4 h after an acute exercise challenge (3 × 10 repetitions, 70% 1-repetition maximum) to assess gene expression of cytokines [IL-6, TNF-α, IL-1β, IL-10, IL-4, interleukin-1 receptor antagonist (IL-1Ra), and transforming growth factor-β (TGF-β)], chemokines [IL-8 and monocyte chemoattractant protein-1 (MCP-1)], cyclooxygenase enzymes [cyclooxygenase-1 and -2 (COX-1 and COX-2, respectively), prostaglandin E2 synthases [microsomal prostaglandin E synthase 1 (mPGES-1) and cytosolic prostaglandin E2 synthase (cPGES)] and receptors [prostaglandin E2 receptor EP3 and EP4 subtypes (EP3 and EP4, respectively), and macrophage markers [cluster of differentiation 16b (CD16b) and CD163], as well as basal macrophage abundance (CD68+ cells). Aging led to higher (P ≤ 0.05) circulating IL-6 and skeletal muscle COX-1, mPGES-1, and CD163 expression. However, LLE had significantly lower serum IL-6 levels (P ≤ 0.05 vs. OH) and a predominantly anti-inflammatory muscle profile [higher IL-10 (P ≤ 0.05 vs. YE), TNF-α, TGF-β, and EP4 levels (P ≤ 0.05 vs. OH)]. In OH only, acute exercise increased expression of proinflammatory factors TNF-α, TGF-β, and IL-8 (P ≤ 0.05). LLE had postexercise gene expression similar to YE, except lower IL-10 (P ≤ 0.10), mPGES-1, and EP3 expression (P ≤ 0.05). Thus, although aging led to a proinflammatory profile within blood and muscle, lifelong exercise partially prevented this and generally preserved the acute inflammatory response to exercise seen in young exercising men. Lifelong exercise may positively impact muscle health throughout aging by promoting anti-inflammation in skeletal muscle.NEW & NOTEWORTHY This study assessed a unique population of lifelong aerobic exercising men and demonstrated that their activity status exerts an anti-inflammatory effect in skeletal muscle and circulation. Furthermore, we provide evidence that the inflammatory response to acute exercise is dysregulated by aging but preserved with lifelong exercise, which might improve skeletal muscle resilience to unaccustomed loading and adaptability into late life.

Time-efficient physical training for enhancing cardiovascular function in midlife and older adults: promise and current research gaps

Cardiovascular diseases (CVD) remain the leading cause of death in developed societies, and "midlife" (50-64 yr) and older (65+) men and women bear the great majority of the burden of CVD. Much of the increased risk of CVD in this population is attributable to CV dysfunction, including adverse changes in the structure and function of the heart, increased systolic blood pressure, and arterial dysfunction. The latter is characterized by increased arterial stiffness and vascular endothelial dysfunction. Conventional aerobic exercise training, as generally recommended in public health guidelines, is an effective strategy to preserve or improve CV function with aging. However, <40% of midlife and older adults meet aerobic exercise guidelines, due in part to time availability-related barriers. As such, there is a need to develop evidence-based time-efficient exercise interventions that promote adherence and optimize CV function in these groups. Two promising interventions that may meet these criteria are interval training and inspiratory muscle strength training (IMST). Limited research suggests these modes of training may improve CV function with time commitments of ≤60 min/wk. This review will summarize the current evidence for interval training and IMST to improve CV function in midlife/older adults and identify key research gaps and future directions.

The association between cardiorespiratory fitness and the incidence of common mental health disorders: A systematic review and meta-analysis

BACKGROUND

Physical activity is associated with a lower incidence of common mental health disorder, but less is known about the impact of cardiorespiratory fitness (CRF).

METHODS

In this review, we systematically evaluated the relationship between CRF and the incidence of common mental health disorders in prospective cohort studies. We systematically searched six major electronic databases from inception to 23rd of May 2019. We assessed study quality using the Newcastle-Ottawa scale.

RESULTS

We were able to pool the hazard ratios (HRs) and 95% confidence intervals (CIs) of four studies including at least 27,733,154 person-years of data. We found that low CRF (HR = 1.47, [95% CI 1.23 - 1.76] p < 0.001 I2 = 85.1) and medium CRF (HR = 1.23, [95% CI 1.09 - 1.38] p < 0.001 I2 = 87.20) CRF are associated with a 47% and 23% greater risk of a common mental health disorders respectively, compared with high CRF. We found evidence to suggest a dose-response relationship between CRF and the risk of common mental health disorders.

LIMITATIONS

We were only able to identify a small number of eligible studies from our search and heterogeneity was substantial in the subsequent meta-analysis.

CONCLUSIONS

Our findings indicate that there is a longitudinal association between CRF levels and the risk of a common mental health disorder. CRF levels could be useful for identifying and preventing common mental health disorders at a population-level.

Unexplained exertional intolerance associated with impaired systemic oxygen extraction

PURPOSE

The clinical investigation of exertional intolerance generally focuses on cardiopulmonary diseases, while peripheral factors are often overlooked. We hypothesize that a subset of patients exists whose predominant exercise limitation is due to abnormal systemic oxygen extraction (SOE).

METHODS

We reviewed invasive cardiopulmonary exercise test (iCPET) results of 313 consecutive patients presenting with unexplained exertional intolerance. An exercise limit due to poor SOE was defined as peak exercise (Ca-vO₂)/[Hb] ≤ 0.8 and VO_2max < 80% predicted in the absence of a cardiac or pulmonary mechanical limit. Those with peak (Ca-vO₂)/[Hb] > 0.8, VO_2max ≥ 80%, and no cardiac or pulmonary limit were considered otherwise normal. The otherwise normal group was divided into hyperventilators (HV) and normals (NL). Hyperventilation was defined as peak PaCO₂ < [1.5 × HCO₃ + 6].

RESULTS

Prevalence of impaired SOE as the sole cause of exertional intolerance was 12.5% (32/257). At peak exercise, poor SOE and HV had less acidemic arterial blood compared to NL (pHa = 7.39 ± 0.05 vs. 7.38 ± 0.05 vs. 7.32 ± 0.02, p < 0.001), which was explained by relative hypocapnia (PaCO₂ = 29.9 ± 5.4 mmHg vs. 31.6 ± 5.4 vs. 37.5 ± 3.4, p < 0.001). For a subset of poor SOE, this relative alkalemia, also seen in mixed venous blood, was associated with a normal PvO₂ nadir (28 ± 2 mmHg vs. 26 ± 4, p = 0.627) but increased SvO₂ at peak exercise (44.1 ± 5.2% vs. 31.4 ± 7.0, p < 0.001).

CONCLUSIONS

We identified a cohort of patients whose exercise limitation is due only to systemic oxygen extraction, due to either an intrinsic abnormality of skeletal muscle mitochondrion, limb muscle microcirculatory dysregulation, or hyperventilation and left shift the oxyhemoglobin dissociation curve.

Does High-Intensity Endurance Training Increase the Risk of Atrial Fibrillation? A Longitudinal Study of Left Atrial Structure and Function

BACKGROUND

Exercise mitigates many cardiovascular risk factors associated with atrial fibrillation. Endurance training has been associated with atrial structural changes which can increase the risk for atrial fibrillation. The dose of exercise training required for these changes is uncertain. We sought to evaluate the impact of exercise on left atrial (LA) mechanical and electrical function in healthy, sedentary, middle-aged adults.

METHODS

Sixty-one adults (52±5 years) were randomized to either 10 months of high-intensity exercise training or yoga. At baseline and post-training, all participants underwent maximal exercise stress testing to assess cardiorespiratory fitness, P-wave signal-averaged electrocardiography for filtered P-wave duration and atrial late potentials (root mean square voltage of the last 20 ms), and echocardiography for LA volume, left ventricular end-diastolic volume, and mitral inflow for assessment of LA active emptying. Post-training data were compared with 14 healthy age-matched Masters athletes.

RESULTS

LA volume, Vo₂ max, and left ventricular end-diastolic volume increased in the exercise group (15%, 17%, and 16%, respectively) with no change in control (P<0.0001). LA active emptying decreased post-exercise versus controls (5%; P=0.03). No significant changes in filtered P-wave duration or root mean square voltage of the last 20 ms occurred after exercise training. LA and left ventricular volumes remained below Masters athletes. The athletes had longer filtered P-wave duration but no difference in the frequency of atrial arrhythmia.

CONCLUSIONS

Changes in LA structure, LA mechanical function, and left ventricular remodeling occurred after 10 months of exercise but without significant change in atrial electrical activity. A longer duration of training may be required to induce electrical changes thought to cause atrial fibrillation in middle-aged endurance athletes.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique Identifier: NCT02039154.

Improvement in muscular strength and aerobic capacities in elderly people occurs independently of physical training type or exercise model

OBJECTIVES

Progressive decline of physiological processes with aging is normal. Aging is also associated with decreased functional capacity and onset of many diseases. This study evaluated the changes in physical fitness (PF), body composition (BC), and lipid profile (LP) in elderly men completing different training protocols.

METHODS

Fifty-five men (age 60-80 years) were randomized into the following groups: without training, aerobic training on dry land, combined training on dry land, and combined training in water. Training was conducted for 8 weeks, and PF, LP, and BC were assessed at the beginning and end of the intervention.

RESULTS

Significant improvements were observed in all parameters; however, combined programs on land or in water were more effective at improving strength and aerobic fitness. Combined exercise produced greater effects on BC and LP and some muscle fitness parameters; however, improvements in muscular and aerobic capacities occurred independently of exercise type or model.

CONCLUSION

These results indicate that the effects of training occur regardless of training type or model, and are directly associated with training periodization, adherence, and regularity.

Plasma matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs and aging and lifelong exercise adaptations in ventricular and arterial stiffness

The age-associated increase in cardiac and central arterial stiffness is attenuated with lifelong (>25 years) endurance exercise in a dose-dependent manner. Remodelling of the extracellular matrix of cardiovascular structures may underpin these lifelong exercise adaptations in structural stiffness. The primary aim was to examine whether matrix metalloproteinases (MMPs) and tissue inhibitors of matrix metalloproteinases (TIMPs) levels are associated with aging and lifelong exercise-related changes in cardiac and central arterial stiffness. Plasma MMPs and TIMPs, left ventricular (LV) (LV stiffness constant) and central arterial stiffness (pulse wave velocity) were examined in healthy adults stratified into five groups based on age and lifelong weekly exercise frequency: (1) young sedentary adults (28-50 years), and older adults (>60 years) who had performed either: (a) sedentary (0-1 sessions/week), (b) casual (2-3 sessions/week), (c) committed (4-5 sessions/week) or (d) athletic (≥6 sessions/week) frequency of exercise. MMP-1 was significantly lower in young compared to older sedentary (p = 0.049). Except for TIMP-2 (p = 0.018 versus committed) and the ratio of MMP-2/TIMP-4 (p = 0.047 versus committed), MMP and TIMP expression was not significantly different in lifelong exercise groups (≥casual) compared to the older sedentary group. MMP-1, -3 had a weak positive relationship with central PWV (r = 0.17-0.25, p ≤ 0.050) but there were no significant relationships between MMPs or TIMPs and LV stiffness constant (p ≥ 0.148). In conclusion, there was not a clear or consistent difference in plasma MMPs and TIMPs with lifelong exercise dose despite exhibiting lower cardiovascular stiffness at the highest exercise levels.

The Importance of Resistance Exercise Training to Combat Neuromuscular Aging

Older adults undergoing age-related decrements in muscle health can benefit substantially from resistance exercise training, a potent stimulus for whole muscle and myofiber hypertrophy, neuromuscular performance gains, and improved functional mobility. With the use of advancing technologies, research continues to elucidate the mechanisms of and heterogeneity in adaptations to resistance exercise training beyond differences in exercise prescription. This review highlights the current knowledge in these areas and emphasizes knowledge gaps that require future attention of the field.

O2 Pulse Patterns in Male Master Athletes with Normal and Abnormal Exercise Tests

PURPOSE

The clinical relevance of abnormal exercise testing (ET) results (at least 0.1 mV ST segment depression measured during exercise or recovery in three consecutive beats) in athletes without obstructive coronary artery disease (CAD) is not well understood. It is unknown whether this phenomenon reflects a physiological adaptation to sport or a truly ischemic response and a concomitant attenuated stroke volume (SV) response. The aim of this study was to investigate if athletes with abnormal ET results without obstructive CAD showed signs of an attenuated SV response using cardiopulmonary ET parameters.

METHODS

A total of 78 male master athletes with abnormal ET results without obstructive CAD underwent cardiopulmonary ET. ΔO2 pulse/Δwork rate (WR), ΔV˙O2/ΔWR, and Δheart rate (HR)/ΔWR were assessed and compared with data from 78 male master athletes with normal ET results, matched for age, sports characteristics, and exercise capacity.

RESULTS

The ΔO2 pulse/ΔWR ratio beyond anaerobic threshold in athletes with abnormal ET results was lower than that in athletes with normal ET results (0.73 ± 0.41 vs 1.12 ± 0.54, respectively, P < 0.001). The ΔV˙O2/ΔWR ratio was also lower in athletes with abnormal ET results (0.9 ± 0.2 vs 1.0 ± 0.3, respectively, P = 0.041). Furthermore, these athletes showed a greater increase in HR in the last 2 min of exercise (ΔHR/ΔWR ratio: 1.19 ± 0.5 vs 0.80 ± 0.6, P < 0.001).

CONCLUSION

Athletes with abnormal ET results without obstructive CAD showed an attenuated O2 pulse slope, decreased ΔV˙O2/ΔWR ratio, and increased ΔHR/ΔWR ratio beyond anaerobic threshold when compared with athletes with a normal ET result. These results support the hypothesis that at least a part of the athletes with an abnormal ET in absence of obstructive CAD have an attenuated SV response at high-intensity exercise.

An Update on the Role of Cardiorespiratory Fitness, Structured Exercise and Lifestyle Physical Activity in Preventing Cardiovascular Disease and Health Risk

The cardiovascular disease (CVD) pandemic has placed considerable strain on healthcare systems, quality of life, and physical function, while remaining the leading cause of death globally. Decades of scientific investigations have fortified the protective effects of cardiorespiratory fitness (CRF), exercise training, and physical activity (PA) against the development of CVD. This review will summarize recent efforts that have made significant strides in; 1) the application of novel analytic techniques to increase the predictive utility of CRF; 2) understanding the protective effects of long-term compliance to PA recommendations through large cohort studies with multiple points of assessment; 3) and understanding the potential harms associated with extreme volumes of PA.

Association of Cardiorespiratory Fitness With Long-term Mortality Among Adults Undergoing Exercise Treadmill Testing

IMPORTANCE

Adverse cardiovascular findings associated with habitual vigorous exercise have raised new questions regarding the benefits of exercise and fitness.

OBJECTIVE

To assess the association of all-cause mortality and cardiorespiratory fitness in patients undergoing exercise treadmill testing.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study enrolled patients at a tertiary care academic medical center from January 1, 1991, to December 31, 2014, with a median follow-up of 8.4 years. Data analysis was performed from April 19 to July 17, 2018. Consecutive adult patients referred for symptom-limited exercise treadmill testing were stratified by age- and sex-matched cardiorespiratory fitness into performance groups: low (<25th percentile), below average (25th-49th percentile), above average (50th-74th percentile), high (75th-97.6th percentile), and elite (≥97.7th percentile).

EXPOSURES

Cardiorespiratory fitness, as quantified by peak estimated metabolic equivalents on treadmill testing.

MAIN OUTCOMES AND MEASURES

All-cause mortality.

RESULTS

The study population included 122 007 patients (mean [SD] age, 53.4 [12.6] years; 72 173 [59.2%] male). Death occurred in 13 637 patients during 1.1 million person-years of observation. Risk-adjusted all-cause mortality was inversely proportional to cardiorespiratory fitness and was lowest in elite performers (elite vs low: adjusted hazard ratio [HR], 0.20; 95% CI, 0.16-0.24; P < .001; elite vs high: adjusted HR, 0.77; 95% CI, 0.63-0.95; P = .02). The increase in all-cause mortality associated with reduced cardiorespiratory fitness (low vs elite: adjusted HR, 5.04; 95% CI, 4.10-6.20; P < .001; below average vs above average: adjusted HR, 1.41; 95% CI, 1.34-1.49; P < .001) was comparable to or greater than traditional clinical risk factors (coronary artery disease: adjusted HR, 1.29; 95% CI, 1.24-1.35; P < .001; smoking: adjusted HR, 1.41; 95% CI, 1.36-1.46; P < .001; diabetes: adjusted HR, 1.40; 95% CI, 1.34-1.46; P < .001). In subgroup analysis, the benefit of elite over high performance was present in patients 70 years or older (adjusted HR, 0.71; 95% CI, 0.52-0.98; P = .04) and patients with hypertension (adjusted HR, 0.70; 95% CI, 0.50-0.99; P = .05). Extreme cardiorespiratory fitness (≥2 SDs above the mean for age and sex) was associated with the lowest risk-adjusted all-cause mortality compared with all other performance groups.

CONCLUSIONS AND RELEVANCE

Cardiorespiratory fitness is inversely associated with long-term mortality with no observed upper limit of benefit. Extremely high aerobic fitness was associated with the greatest survival and was associated with benefit in older patients and those with hypertension. Cardiorespiratory fitness is a modifiable indicator of long-term mortality, and health care professionals should encourage patients to achieve and maintain high levels of fitness.

Cardiovascular and skeletal muscle health with lifelong exercise

The purpose of this study was to examine the effects of aerobic lifelong exercise (LLE) on maximum oxygen consumption (V̇o_2max) and skeletal muscle metabolic fitness in trained women ( n = 7, 72 ± 2 yr) and men ( n = 21, 74 ± 1 yr) and compare them to old, healthy nonexercisers (OH; women: n = 10, 75 ± 1 yr; men: n = 10, 75 ± 1 yr) and young exercisers (YE; women: n = 10, 25 ± 1 yr; men: n = 10, 25 ± 1 yr). LLE men were further subdivided based on intensity of lifelong exercise and competitive status into performance (LLE-P, n = 14) and fitness (LLE-F, n = 7). On average, LLE exercised 5 day/wk for 7 h/wk over the past 52 ± 1 yr. Each subject performed a maximal cycle test to assess V̇o_2max and had a vastus lateralis muscle biopsy to examine capillarization and metabolic enzymes [citrate synthase, β-hydroxyacyl-CoA dehydrogenase (β-HAD), and glycogen phosphorylase]. V̇o_2max had a hierarchical pattern (YE > LLE > OH, P < 0.05) for women (44 ± 2 > 26 ± 2 > 18 ± 1 ml·kg^-1·min^-1) and men (53 ± 3 > 34 ± 1 > 22 ± 1 ml·kg^-1·min^-1) and was greater ( P < 0.05) in LLE-P (38 ± 1 ml·kg^-1·min^-1) than LLE-F (27 ± 2 ml·kg^-1·min^-1). LLE men regardless of intensity and women had similar capillarization and aerobic enzyme activity (citrate synthase and β-HAD) as YE, which were 20%-90% greater ( P < 0.05) than OH. In summary, these data show a substantial V̇o_2max benefit with LLE that tracked similarly between the sexes, with further enhancement in performance-trained men. For skeletal muscle, 50+ years of aerobic exercise fully preserved capillarization and aerobic enzymes, regardless of intensity. These data suggest that skeletal muscle metabolic fitness may be easier to maintain with lifelong aerobic exercise than more central aspects of the cardiovascular system. NEW & NOTEWORTHY Lifelong exercise (LLE) is a relatively new and evolving area of study with information especially limited in women and individuals with varying exercise intensity habits. These data show a substantial maximal oxygen consumption benefit with LLE that tracked similarly between the sexes. Our findings contribute to the very limited skeletal muscle biopsy data from LLE women (>70 yr), and similar to men, revealed a preserved metabolic phenotype comparable to young exercisers.

Carotid Arterial Stiffness and Hemodynamic Responses to Acute Cycling Intervention at Different Times during 12-Week Supervised Exercise Training Period

This paper studied the alterations in arterial stiffness and hemodynamic responses during resting state and immediately following acute cycling intervention at different times across 12-week supervised exercise training. Twenty-six sedentary young males participated in the exercise training program at moderate intensity. Arterial stiffness and hemodynamic variables of the right common carotid artery were measured and computed during resting state and immediately following acute cycling intervention at weeks 0, 4, 8, and 12. Across the 12-week exercise training, carotid arterial stiffness was decreased at weeks 8 and 12 and hemodynamic variables were improved at week 12 during resting state. In response to acute cycling intervention, carotid arterial stiffness exhibited an acute increase foremost at 8 weeks, and arterial maximal and mean diameters showed acute decreases at weeks 0 and 4. Despite significant differences in arterial stiffness and hemodynamic variables between resting state and immediately after acute intervention for each time period, these differences presented a progressive decrease across the 12-week exercise training. In conclusion, long-term exercise training not only improved carotid arterial stiffness and hemodynamic alterations when at rest but also negated the acute responses of carotid arterial stiffness and hemodynamic variables to acute cycling intervention.

Muscle morphology and performance in master athletes: A systematic review and meta-analyses

INTRODUCTION

The extent to which chronic exercise training preserves age-related decrements in physical function, muscle strength, mass and morphology is unclear. Our aim was to conduct a systematic review of the literature to determine to what extent chronically trained master athletes (strength/power and endurance) preserve levels of physical function, muscle strength, muscle mass and morphology in older age, compared with older and younger controls and young trained individuals.

METHODS

The systematic data search included Medline, EMBASE, SPORTDiscus, CINAHL and Web of Science databases.

INCLUSION CRITERIA

i) master athletes mean exercise training duration ≥20 years ii) master athletes mean age of cohort >59 years) iii) at least one measurement of muscle mass/volume/fibre-type morphology and/or strength/physical function.

RESULTS

Fifty-five eligible studies were identified. Meta-analyses were carried out on maximal aerobic capacity, maximal voluntary contraction and body composition. Master endurance athletes (42.0 ± 6.6 ml kg^-1 min^-1) exhibited VO_2max values comparable with young healthy controls (43.1 ± 6.8 ml kg^-1 min^-1, P = .84), greater than older controls (27.1 ± 4.3 ml kg^-1 min^-1, P < 0.01) and master strength/power athletes (26.5 ± 2.3 mlkg^-1 min^-1, P < 0.01), and lower than young endurance trained individuals (60.0 ± 5.4 ml kg^-1 min^-1, P < 0.01). Master strength/power athletes (0.60 (0.28-0.93) P < 0.01) and young controls (0.71 (0.06-1.36) P < 0.05) were significantly stronger compared with the other groups. Body fat% was greater in master endurance athletes than young endurance trained (-4.44% (-8.44 to -0.43) P < 0.05) but lower compared with older controls (7.11% (5.70-8.52) P < 0.01).

CONCLUSION

Despite advancing age, this review suggests that chronic exercise training preserves physical function, muscular strength and body fat levels similar to that of young, healthy individuals in an exercise mode-specific manner.

The effect of lifelong exercise frequency on arterial stiffness

KEY POINTS

This study examined the effect of different 'doses' of lifelong (>25 years) exercise on arterial stiffening (a hallmark of vascular ageing) in older adults. There are clear dose-dependent effects of lifelong exercise training on human arterial stiffness that vary according to the site and size of the arteries. Similar to what we have observed previously with ventricular stiffening, 4-5 days week^-1 of committed exercise over a lifetime are necessary to preserve 'youthful' vascular compliance, especially of the large central arteries. Casual exercise training of two to three times per week may be sufficient for middle-sized arteries like the carotid to minimize arterial stiffening with ageing. However, there is little effect of exercise training on the small-sized peripheral arteries at any dose.

ABSTRACT

Central arterial stiffness increases with sedentary ageing. While near-daily, vigorous lifelong (>25 years) endurance exercise training prevents arterial stiffening with ageing, this rigorous routine of exercise training over a lifetime is impractical for most individuals. The aim was to examine whether a less frequent 'dose' of lifelong exercise training (four to five sessions per week for > 30 min) that is consistent with current physical activity recommendations elicits similar benefits on central arterial stiffening with ageing. A cross-sectional examination of 102 seniors (>60 years old) who had a consistent lifelong exercise history was performed. Subjects were stratified into four groups based on exercise frequency as an index of exercise 'dose': sedentary: fewer than two sessions per week; casual exercisers: two to three sessions per week; committed exercisers: four to five sessions per week; and Masters athletes: six to seven sessions per week plus regular competitions. Detailed measurements of arterial stiffness and left ventricular afterload were collected. Biological aortic age and central pulse wave velocity were younger in committed exercisers and Masters athletes compared to sedentary seniors. Total arterial compliance index (TACi) was lower, while carotid β-stiffness index and effective arterial elastance were higher in sedentary seniors compared to the other groups. There appeared to be a dose-response threshold for carotid β-stiffness index and TACi. Peripheral arterial stiffness was not significantly different among the groups. These data suggest that four to five weekly exercise sessions over a lifetime is associated with reduced central arterial stiffness in the elderly. A less frequent dose of lifelong exercise (two to three sessions per week) is associated with decreased ventricular afterload and peripheral resistance, while peripheral arterial stiffness is unaffected by any dose of exercise.

The Complex Phenotype of the Athlete's Heart: Implications for Preparticipation Screening

Preparticipation screening is vital to exclude inherited cardiac conditions that have the potential to cause sudden cardiac death in seemingly healthy athletes. Recent research has questioned traditional theories of load-induced, dichotomous cardiac adaptation. We therefore considered whether a one-size-fits-all approach to screening can account for interindividual differences brought about by sporting discipline, training volume, ethnicity, body size, sex, and age.

Lifelong Physical Activity Regardless of Dose Is Not Associated With Myocardial Fibrosis

BACKGROUND

Recent reports have suggested that long-term, intensive physical training may be associated with adverse cardiovascular effects, including the development of myocardial fibrosis. However, the dose-response association of different levels of lifelong physical activity on myocardial fibrosis has not been evaluated.

METHODS AND RESULTS

Seniors free of major chronic illnesses were recruited from predefined populations based on the consistent documentation of stable physical activity over >25 years and were classified into 4 groups by the number of sessions/week of aerobic activities ≥30 minutes: sedentary (group 1), <2 sessions; casual (group 2), 2 to 3 sessions; committed (group 3), 4 to 5 sessions; and Masters athletes (group 4), 6 to 7 sessions plus regular competitions. All subjects underwent cardiopulmonary exercise testing and cardiac magnetic resonance imaging, including late gadolinium enhancement assessment of fibrosis. Ninety-two subjects (mean age 69 years, 27% women) were enrolled. No significant differences in age or sex were seen between groups. Median peak oxygen uptake was 25, 26, 32, and 40 mL/kg/min for groups 1, 2, 3, and 4, respectively. Cardiac magnetic resonance imaging demonstrated increasing left ventricular end-diastolic volumes, end-systolic volumes, stroke volumes, and masses with increasing doses of lifelong physical activity. One subject in group 2 had late gadolinium enhancement in a noncoronary distribution, and no subjects in groups 3 and 4 had evidence of late gadolinium enhancement.

CONCLUSIONS

A lifelong history of consistent physical activity, regardless of dose ranging from sedentary to competitive marathon running, was not associated with the development of focal myocardial fibrosis.

Association of physical activity and appetite with visual function related to driving competence in older adults

Background

Older people are at greater risk of traffic accidents, partially because of age-related declines in visual function, including reduced useful field of view (UFOV). However, lifestyle factors which cause age-related decline in UFOV remain poorly understood. We conducted a study to investigate whether physical activity and appetite status were related to UFOV test performance in healthy older adults.

Methods

Thirty community-dwelling older people (age 68.6 ± 3.1 years, 15 females) were enrolled in this study. Each participant completed the Council on Nutrition appetite questionnaire (CNAQ) and a UFOV test. They then wore a tri-axial accelerometer (Active style Pro HJA-350IT) for 3–6 consecutive days to objectively measure their PA in free-living conditions.

Results

Longer time spent in vigorous physical activity was significantly associated with better UFOV test performance when adjusted for age and accelerometer wear time (non-locomotive: r = −0.435, locomotive: r = −0.449; n = 25). In addition, male, but not female, participants with a higher CNAQ score had significantly better UFOV test performance in both an unadjusted model (r = −0.560; n = 15) and a model adjusted for age (r = −0.635; n = 15).

Conclusions

The results suggest that appetite status among males and time spent in high intensity PA are associated with visual function related to driving competence in older adults.

Sport-specific influences on respiratory patterns in elite athletes

OBJECTIVE:

To examine differences in lung function among sports that are of a similar nature and to determine which anthropometric/demographic characteristics correlate with lung volumes and flows.

METHODS:

This was a cross-sectional study involving elite male athletes (N = 150; mean age, 21 ± 4 years) engaging in one of four different sports, classified according to the type and intensity of exercise involved. All athletes underwent full anthropometric assessment and pulmonary function testing (spirometry).

RESULTS:

Across all age groups and sport types, the elite athletes showed spirometric values that were significantly higher than the reference values. We found that the values for FVC, FEV₁, vital capacity, and maximal voluntary ventilation were higher in water polo players than in players of the other sports evaluated (p < 0.001). In addition, PEF was significantly higher in basketball players than in handball players (p < 0.001). Most anthropometric/demographic parameters correlated significantly with the spirometric parameters evaluated. We found that BMI correlated positively with all of the spirometric parameters evaluated (p < 0.001), the strongest of those correlations being between BMI and maximal voluntary ventilation (r = 0.46; p < 0.001). Conversely, the percentage of body fat correlated negatively with all of the spirometric parameters evaluated, correlating most significantly with FEV₁ (r = −0.386; p < 0.001).

CONCLUSIONS:

Our results suggest that the type of sport played has a significant impact on the physiological adaptation of the respiratory system. That knowledge is particularly important when athletes present with respiratory symptoms such as dyspnea, cough, and wheezing. Because sports medicine physicians use predicted (reference) values for spirometric parameters, the risk that the severity of restrictive disease or airway obstruction will be underestimated might be greater for athletes.

The effect of 1 year of Alagebrium and moderate-intensity exercise training on left ventricular function during exercise in seniors: a randomized controlled trial

Sedentary aging leads to left ventricular (LV) and vascular stiffening due in part to advanced glycation end-products (AGEs) cross-linking of extracellular matrix proteins. Vigorous lifelong exercise ameliorates age-related cardiovascular (CV) stiffening and enhances exercise LV function, although this effect is limited when exercise is initiated later in life. We hypothesized that exercise training might be more effective at improving the impact of age-related CV stiffening during exercise when combined with an AGE cross-link breaker (Alagebrium). Sixty-two seniors (≥60 yr) were randomized into four groups: sedentary + placebo, sedentary + Alagebrium, exercise + placebo, and exercise + Alagebrium for 1 yr. Moderate-intensity aerobic exercise was performed 3-4 sessions/wk; controls underwent similar frequency of yoga/balance training. Twenty-four similarly-aged, lifelong exercisers (4-5 sessions/wk) served as a comparator for the effect of lifelong exercise on exercising LV function. Oxygen uptake (Douglas bags), stroke index (SI; acetylene rebreathing), and effective arterial elastance (Ea) were collected at rest and submaximal and maximal exercise. Maximum O2 uptake (23 ± 5 to 25 ± 6 ml·kg(-1)·min(-1)) increased, while SI (35 ± 11 to 39 ± 12 ml/m(2)) and Ea (4.0 ± 1.1 to 3.7 ± 1.2 mmHg·ml(-1)·m(-2)) were improved across all conditions with exercise, but remained unchanged in controls (exercise × time, P ≤ 0.018). SI or Ea were not affected by Alagebrium (medication × time, P ≥ 0.468) or its combination with exercise (interaction P ≥ 0.252). After 1 yr of exercise plus Alagebrium, exercise SI and Ea remained substantially below that of lifelong exercisers (15-24 and 9-22%, respectively, P ≤ 0.415). In conclusion, Alagebrium plus exercise had no synergistic effect on exercise LV function and failed to achieve levels associated with lifelong exercise, despite a similar exercise frequency.

Cardiorespiratory Improvements Achieved by American College of Sports Medicine's Exercise Prescription Implemented on a Mobile App

Background

Strong evidence shows that an increase in cardiorespiratory fitness (CRF) and physical activity (PA) reduces cardiovascular disease risk.

Objective

To test whether a scientifically endorsed program to increase CRF and PA, implemented on an easy-to-use, always-accessible mobile app would be effective in improving CRF.

Methods

Of 63 healthy volunteers participating, 18 tested the user interface of the Cardio-Fitness App (CF-App); and 45 underwent a 2-week intervention period, of whom 33 eventually concluded it. These were assigned into three groups. The Step-based App (Step-App) group (n=8), followed 10,000 steps/day prescription, the CF-App group (n=13), and the Supervised Cardio-Fitness (Super-CF) group (n=12), both followed a heart rate (HR)-based program according to American College of Sports Medicine (ACSM) guidelines, but either implemented on the app, or at the gym, respectively. Participants were tested for CRF, PA, resting systolic and diastolic blood pressures (SBP, DBP), resting, exercise, and recovery HR.

Results

CRF increased in all groups (+4.9%; P<.001). SBP decreased in all groups (-2.6 mm Hg; P=.03). DBP decrease was higher in the Super-CF group (-3.5 mm Hg) than in the Step-App group (-2.1 mm Hg; P<.001). Posttest exercise HR decreased in all groups (-3.4 bpm; P=.02). Posttest recovery HR was lower in the Super-CF group (-10.1 bpm) than in the other two groups (CF-App: -4.9 bpm, Step-App: -3.3 bpm; P<.001). The CF-App group, however, achieved these improvements with more training heart beats (P<.01).

Conclusions

A 10,000 steps/day target-based app improved CRF similar to an ACSM guideline-based program whether it was implemented on a mobile app or in supervised gym sessions.

Associations between physical activity and health-related fitness - volume versus pattern

Approximately 3.2 million people die of non-communicable diseases (NCD) each year due to insufficient physical activity. Physical activity guidelines are possibly perceived as too demanding and might thus pose a barrier. We addressed the question if a more stable physical activity pattern is associated with higher levels of health-related fitness than one with high and low intensities, regardless of the physical activity level (PAL). Physical activity was objectively measured in 296 men and women (53.7 ± 8.94 years) with the SenseWear Pro Armband^®. Using this data, the PAL and a Gini index were calculated to report the physical activity pattern. Health-related fitness was expressed as a fitness index. PAL was weakly correlated to health-related fitness (r = 0.38, P < .0001). The Gini index was also weakly correlated to the fitness index (r = 0.23, P < .0001). Results of the ANCOVA showed that participants in the first quartile of PAL always scored significantly lower for health-related fitness than participants in quartile four, after adjustment for the Gini index. These results suggest that as long as the volume of physical activity is high, health-related fitness will be high as well, independent of the physical activity pattern or variability in intensities throughout the day.

Altered left ventricular performance in aging physically active mice with an ankle sprain injury

We assessed the impact of differing physical activity levels throughout the lifespan, using a musculoskeletal injury model, on the age-related changes in left ventricular (LV) parameters in active mice. Forty male mice (CBA/J) were randomly placed into one of three running wheel groups (transected CFL group, transected ATFL/CFL group, SHAM group) or a SHAM Sedentary group (SHAMSED). Before surgery and every 6 weeks after surgery, LV parameters were measured under 2.5 % isoflurane inhalation. Group effects for daily distance run was significantly greater for the SHAM and lesser for the ATLF/CFL mice (p = 0.013) with distance run decreasing with age for all mice (p < 0.0001). Beginning at 6 months of age, interaction (group × age) was noted with LV posterior wall thickness-to-radius ratios (h/r) where h/r increased with age in the ATFL/CFL and SHAMSED mice while the SHAM and CFL mice exhibited decreased h/r with age (p = 0.0002). Passive filling velocity (E wave) was significantly greater in the SHAM mice and lowest for the ATFL/CFL and SHAMSED mice (p < 0.0001) beginning at 9 months of age. Active filling velocity (A wave) was not different between groups (p = 0.10). Passive-to-active filling velocity ratio (E/A ratio) was different between groups (p < 0.0001), with higher ratios for the SHAM mice and lower ratios for the ATFL/CFL and SHAMSED mice in response to physical activity beginning at 9 months of age. Passive-to-active filling velocity ratio decreased with age (p < 0.0001). Regular physical activity throughout the lifespan improved LV structure, passive filling velocity, and E/A ratio by 6 to 9 months of age and attenuated any negative alterations throughout the second half of life. The diastolic filling differences were found to be significantly related to the amount of activity performed by 9 months and at the end of the lifespan.

Cardiovascular Adaptations to Exercise Training

Aerobic exercise training leads to cardiovascular changes that markedly increase aerobic power and lead to improved endurance performance. The functionally most important adaptation is the improvement in maximal cardiac output which is the result of an enlargement in cardiac dimension, improved contractility, and an increase in blood volume, allowing for greater filling of the ventricles and a consequent larger stroke volume. In parallel with the greater maximal cardiac output, the perfusion capacity of the muscle is increased, permitting for greater oxygen delivery. To accommodate the higher aerobic demands and perfusion levels, arteries, arterioles, and capillaries adapt in structure and number. The diameters of the larger conduit and resistance arteries are increased minimizing resistance to flow as the cardiac output is distributed in the body and the wall thickness of the conduit and resistance arteries is reduced, a factor contributing to increased arterial compliance. Endurance training may also induce alterations in the vasodilator capacity, although such adaptations are more pronounced in individuals with reduced vascular function. The microvascular net increases in size within the muscle allowing for an improved capacity for oxygen extraction by the muscle through a greater area for diffusion, a shorter diffusion distance, and a longer mean transit time for the erythrocyte to pass through the smallest blood vessels. The present article addresses the effect of endurance training on systemic and peripheral cardiovascular adaptations with a focus on humans, but also covers animal data.

Endurance training and maximal oxygen consumption with ageing: Role of maximal cardiac output and oxygen extraction

BACKGROUND

The increase in maximal oxygen consumption (VO2max) with endurance training is associated with that of maximal cardiac output (Qmax), but not oxygen extraction, in young individuals. Whether such a relationship is altered with ageing remains unclear. Therefore, we sought systematically to review and determine the effect of endurance training on and the associations among VO2max, Qmax and arteriovenous oxygen difference at maximal exercise (Ca-vO2max) in healthy aged individuals.

DESIGN AND METHODS

We conducted a systematic search of MEDLINE, Scopus and Web of Science, from their inceptions until May 2015 for articles assessing the effect of endurance training lasting 3 weeks or longer on VO2max and Qmax and/or Ca-vO2max in healthy middle-aged and/or older individuals (mean age ≥40 years). Meta-analyses were performed to determine the standardised mean difference (SMD) in VO2max, Qmax and Ca-vO2max between post and pre-training measurements. Subgroup and meta-regression analyses were used to evaluate the associations among SMDs and potential moderating factors.

RESULTS

Sixteen studies were included after systematic review, comprising a total of 153 primarily untrained healthy middle-aged and older subjects (mean age 42-71 years). Endurance training programmes ranged from 8 to 52 weeks of duration. After data pooling, VO2max (SMD 0.89; P < 0.0001) and Qmax (SMD 0.61; P < 0.0001) were increased after endurance training; no heterogeneity among studies was detected. Ca-vO2max was only increased with endurance training interventions lasting more than 12 weeks (SMD 0.62; P = 0.001). In meta-regression, the SMD in Qmax was positively associated with the SMD in VO2max (B = 0.79, P = 0.04). The SMD in Ca-vO2max was not associated with the SMD in VO2max (B = 0.09, P = 0.84).

CONCLUSIONS

The improvement in VO2max following endurance training is a linear function of Qmax, but not Ca-vO2max, through healthy ageing.

Low-frequency severe-intensity interval training improves cardiorespiratory functions

PURPOSE

The present study investigated the effects of severe-intensity interval training at a frequency of once a week on cardiorespiratory function at rest and during exercise.

METHODS

Fourteen young healthy males were randomly assigned to either an interval training group or control group. Cardiorespiratory function was investigated by incremental maximal exercise test and constant work rate submaximal exercise test before and after the intervention period in all subjects. Submaximal exercise test was conducted at two work rates (80% ventilatory threshold (VT) level and 100% VT level plus 50% of the difference between VT and peak oxygen consumption (V˙O2)) for 8 min; the same work rates and duration were used before and after training. Left ventricular adaptations were assessed by echocardiography under supine resting conditions before and after training. In the interval training group, seven subjects performed cycle ergometer training once per week for 3 months. The training consisted of three bouts of exercises to volitional fatigue at 80% maximum work rate.

RESULTS

Increased V˙O2max (+13%, P = 0.015), VT (+21%, P = 0.001), and left ventricular posterior wall thickness (+18%, P = 0.002) and reduced minute ventilation (-12%, P = 0.032) and blood lactate concentration (-16%, P = 0.025) during high-intensity exercise were observed after the training program compared with baseline. Although not significant, V˙O2 and cycling economy (V˙O2 per work rate) during high-intensity exercise decreased slightly after training.

CONCLUSION

The present results indicate that severe-intensity interval training, even when performed at a low frequency, markedly improves cardiorespiratory function as well as induces cardiac morphological adaptations involving left ventricular hypertrophy and cardiorespiratory metabolic response during submaximal exercise. The present findings may provide new insights for low-frequency, severe-intensity interval training in the field of sports science.

Effects of endurance, circuit, and relaxing training on cardiovascular risk factors in hypertensive elderly patients

Recommendations for prevention of cardiovascular diseases (CVDs) risk factors among older adults highlighted the importance of exercise-based interventions, including endurance training (ET). However, the evidence of efficacy of other interventions based on short-bouts of exercise (circuit training, CT), and the practice of breath-control and meditation (relaxing training, RT) is growing. The aim of this study was to elucidate if CT or RT are equally effective in CVD risk factors reduction compared to ET. To this purpose, in 40 elderly participants, with clinically diagnosed grade 1 hypertension, resting blood pressure, blood glucose, and cholesterol levels, peak oxygen uptake ([Formula: see text]), mechanical efficiency and quality of life were evaluated before and after 12 weeks of ET, CT, and RT treatments. Resting blood pressure reduced significantly in all groups by ∼11 %. In ET, blood cholesterol levels (-18 %), [Formula: see text] (+8 %), mechanical efficiency (+9 %), and quality of life scores (+36 %) ameliorated. In CT blood glucose levels (-11 %), [Formula: see text] (+7 %) and quality of life scores (+35 %) were bettered. Conversely, in RT, the lower blood pressure went along only with an improvement in the mental component of quality of life (+42 %). ET and CT were both appropriate interventions to reduce CVDs risk factors, because blood pressure reduction was accompanied by decreases in blood glucose and cholesterol levels, increases in [Formula: see text], mechanical efficiency, and quality of life. Although RT influenced only blood pressure and quality of life, this approach would be an attractive alternative for old individuals unable or reluctant to carry out ET or CT.

Fatiguing exercise initiated later in life reduces incidence of fibrillation and improves sleep quality in Drosophila

As the human body ages, the risk of heart disease and stroke greatly increases. While there is evidence that lifelong exercise is beneficial to the heart's health, the effects of beginning exercise later in life remain unclear. This study aimed to investigate whether exercise training started later in life is beneficial to cardiac aging in Drosophila. We examined 4-week-old wild-type virgin female flies that were exposed to exercise periods of either 1.5, 2.0, or 2.5 h per day, 5 days a week for 2 weeks. Using M-mode traces to analyze cardiac function by looking at parameters including heart rate, rhythmicity, systolic and diastolic diameter, and interval and fractional shortening, we found that cardiac function declined with age, shown by an increase in the number of fibrillation events and a decrease in fractional shortening. About 2.0 and 2.5 h of exercise per day displayed a reduced incidence of fibrillation events, and only physical exercise lasting 2.5-h period increased fractional shortening and total sleep time in Drosophila. These data suggested that training exercise needs to be performed for longer duration to exert physiological benefits for the aging heart. Additionally, climbing ability to assess the exercise-induced muscle fatigue was also measured. We found that 2.0 and 2.5 h of exercise caused exercise-induced fatigue, and fatiguing exercise is beneficial for cardiac and healthy aging overall. This study provides a basis for further study in humans on the impact of beginning an exercise regimen later in life on cardiac health.

Circulating inflammatory miRNA signature in response to different doses of aerobic exercise

While moderate acute exercise has been associated with strong anti-inflammatory mechanisms, strenuous exercise has been linked to deleterious inflammatory perturbations. It is therefore fundamental to elucidate the mechanisms that regulate the exercise-induced inflammatory cascade. Information on novel regulators such as circulating inflammatory microRNAs (c-inflammamiRs) is incomplete. In this study, we evaluated the response of a panel of c-inflammamiRs to different doses of acute aerobic exercise. We first studied the exercise-induced inflammatory cascade in serum samples of nine active middle-aged males immediately before and after (0 h, 24 h, 72 h) 10-km, half-marathon, and marathon races. Next, we analyzed the circulating profile of 106 specific c-inflammamiRs immediately before) and after (0 h, 24 h) 10-km (low inflammatory response) and marathon (high inflammatory response) races. Analysis of classical inflammatory parameters revealed a dose-dependent effect of aerobic exercise on systemic inflammation, with higher levels detected after marathon. We observed an increase in miR-150-5p immediately after the 10-km race. Levels of 12 c-inflammamiRs were increased immediately after the marathon (let-7d-3p, let-7f-2-3p, miR-125b-5p, miR-132-3p, miR-143-3p, miR-148a-3p, miR-223-3p, miR-223-5p, miR-29a-3p, miR-34a-5p, miR-424-3p, and miR-424-5p). c-inflammamiRs returned to basal levels after 24 h. Correlation and in silico analyses supported a close association between the observed c-inflammamiR pattern and regulation of the inflammatory process. In conclusion, we found that different doses of acute aerobic exercise induced a distinct and specific c-inflammamiR response, which may be associated with control of the exercise-induced inflammatory cascade. Our findings point to c-inflammamiRs as potential biomarkers of exercise-induced inflammation, and hence, exercise dose.

Age-related decline in mitral peak diastolic velocities is unaffected in well-trained runners

OBJECTIVES

We examined whether diastolic left ventricular function in young and senior lifelong endurance runners was significantly different from that in sedentary age-matched controls, and whether lifelong endurance running appears to modify the age-related decline in diastolic left ventricular function.

DESIGN

The study comprised 17 senior athletes (age: 59-75 years, running distance: 30-70 km/week), 10 young athletes (age: 20-36 years, matched for running distance), and 11 senior and 12 young weight-matched sedentary controls. Peak early (E) and late (A) mitral inflow and early (e') and late (a') diastolic and systolic (s') annular longitudinal tissue Doppler velocities were measured by echocardiography during four stages (rest, supine bike exercise at 30% and 60% of maximal workload, and recovery).

RESULTS

The athletes had marked cardiac remodeling, while overall differences in mitral inflow and annular tissue Doppler velocities during rest and exercise were more associated with age than with training status. The senior participants had lower E/A at rest, overall lower E, e' and s', and greater E/e' compared to the young participants (all values of P < 0.05). The athletes had greater E/A (P = 0.004), but tissue Doppler velocities were not different from those of the controls.

CONCLUSIONS

Lifelong endurance running was not found to be associated with major attenuation of the age-related decline in diastolic function at rest or during exercise.

Maximal cardiac output in athletes: influence of age

BACKGROUND

The decline in maximal oxygen consumption (VO2max) with age seems to be exacerbated in endurance-trained athletes (EA) relative to untrained healthy subjects. Whether maximal cardiac output (Qmax) parallels this group-specific decline with age remains uncertain. Therefore, we sought to systematically review the literature and determine whether Qmax is similarly enhanced in EA across all ages relative to age-matched untrained counterparts.

DESIGN AND METHODS

We conducted a systematic search of MEDLINE, Cochrane and Web of Science from their inceptions until June 2014 for articles evaluating Qmax in athletes. A meta-analysis was performed to determine the standardized mean difference (SMD) in Qmax between EA and age-matched untrained healthy subjects. Included studies had to (i) comprise EA and control groups matched for body size or (ii) present Qmax values normalized for body size. Subgroup and meta-regression analyses were used to study the influence of age and potential moderating factors.

RESULTS

Eighteen studies were selected after systematic review, comprising 268 EA and 232 age-matched untrained subjects. Nine studies involved young EA (mean age ≤40 years) while nine studies involved master EA (mean age >55 years). After data pooling, young and master EA groups showed higher Qmax compared with control groups (SMD = 1.49 and SMD = 1.68, respectively; both p < 0.0001). The SMD in Qmax between EA and control groups was similar in studies in young EA compared with studies in master EA (p = 0.61). Moreover, the SMD in VO2max between EA and control groups did not differ in studies in young EA compared with studies in master EA (p = 0.37). In meta-regression analyses, the difference in percentage of body fat between EA and control groups was inversely associated with the SMD in Qmax (B = - 0.17, p = 0.01) and the SMD in VO2max (B = -0.20, p = 0.01). Mean age was not associated with the SMD in Qmax (B = -0.001, P = 0.90) nor with the SMD in VO2max (B = 0.01, P = 0.58).

CONCLUSIONS

Based on current published studies, the enhanced Qmax observed in EA compared with untrained healthy subjects matched for body size is not affected by age but may be related, at least in part, to the improved body composition of EA.

An investigation into the relationship between age and physiological function in highly active older adults

KEY POINTS

The relationship between age and physiological function remains poorly defined and there are no physiological markers that can be used to reliably predict the age of an individual. This could be due to a variety of confounding genetic and lifestyle factors, and in particular to ill-defined and low levels of physical activity. This study assessed the relationship between age and a diverse range of physiological functions in a cohort of highly active older individuals (cyclists) aged 55-79 years in whom the effects of lifestyle factors would be ameliorated. Significant associations between age and function were observed for many functions. V̇O2max was most closely associated with age, but even here the variance in age for any given level was high, precluding the clear identification of the age of any individual. The data suggest that the relationship between human ageing and physiological function is highly individualistic and modified by inactivity.

ABSTRACT

Despite extensive research, the relationship between age and physiological function remains poorly characterised and there are currently no reliable markers of human ageing. This is probably due to a number of confounding factors, particularly in studies of a cross-sectional nature. These include inter-subject genetic variation, as well as inter-generational differences in nutrition, healthcare and insufficient levels of physical activity as well as other environmental factors. We have studied a cohort of highly and homogeneously active older male (n = 84) and female (n = 41) cyclists aged 55-79 years who it is proposed represent a model for the study of human ageing free from the majority of confounding factors, especially inactivity. The aim of the study was to identify physiological markers of ageing by assessing the relationship between function and age across a wide range of indices. Each participant underwent a detailed physiological profiling which included measures of cardiovascular, respiratory, neuromuscular, metabolic, endocrine and cognitive functions, bone strength, and health and well-being. Significant associations between age and function were observed for many functions. The maximal rate of oxygen consumption (V̇O2max) showed the closest association with age (r = -0.443 to -0.664; P < 0.001), but even here the variance in age for any given level was high, precluding the clear identification of the age of any individual. The results of this cross-sectional study suggest that even when many confounding variables are removed the relationship between function and healthy ageing is complex and likely to be highly individualistic and that physical activity levels must be taken into account in ageing studies.

Effect of combined aerobic and resistance training versus aerobic training on arterial stiffness

BACKGROUND

While aerobic exercise training may decrease arterial stiffness, the impact of combined aerobic and resistance training is unclear. Therefore, the aim of this study was to systematically review and quantify the effect of combined aerobic and resistance training on arterial stiffness, as determined by arterial pulse wave velocity (PWV), and compare it with aerobic training.

METHODS

MEDLINE, EMBASE and Web of Science were searched through November 2013 for randomized controlled trials evaluating the effect of aerobic or combined aerobic and resistance training on PWV. A meta-analysis was performed to determine the standardized mean difference (SMD) in PWV between exercise and control groups. Subgroup analyses were used to study potential moderating factors.

RESULTS

Twenty-one randomized controlled trials comparing exercise and control groups (overall n=752), met the inclusion criteria. After data pooling, PWV was decreased in aerobic trained groups compared with controls (10 trials, SMD=-0.52, 95% CI= -0.76, -0.27; P<0.0001) but did not reach statistical significance in combined trained groups compared with controls (11 trials, SMD=-0.23, 95% CI=-0.50, 0.04; P=0.10). The effect in aerobic trained groups did not differ compared with combined trained groups (P=0.12). In addition, aerobic training resulted in significantly lower SMD in PWV compared with combined training in interventions including a higher volume of aerobic training or assessing carotid-femoral PWV.

CONCLUSIONS

These data suggest that combined aerobic and resistance training interventions may have reduced beneficial effects on arterial stiffness compared with control interventions, but do not appear to differ significantly with aerobic training alone.

Physical activity versus cardiorespiratory fitness: two (partly) distinct components of cardiovascular health?

Physical activity (PA) and cardiorespiratory fitness (CRF) both have inverse relationships to cardiovascular (CV) morbidity and mortality. Recent position papers and guidelines have identified the important role of both of these factors in CV health. The benefits of PA and CRF in the prevention of CV disease and risk factors are reviewed. In addition, assessment methodology and utilization in the research and clinical arenas are discussed. Finally, the benefits, methodology, and utilization are compared and contrasted to better understand the two (partly) distinct components and their impact on CV health.