Effects of home-based exergaming on child social cognition and subsequent prediction of behavior.

The use of exergames may be one viable way to increase child physical activity, but investigation of its effects on motivation over time and prediction of adherence have seen little research attention. The purpose of this study was to compare the effect of two cycling exergame interventions (single-player, multi-player) among children aged 9-12 years on motivational variables (theory of planned behavior) and to explore whether these variables could predict objective assessment of playtime across 6 weeks. Sixty-nine insufficiently active children were recruited through advertisements within the community/schools and randomized to either the single play condition (n = 30) or multi-player condition (n = 39). Exergaming use was recorded objectively via game logs and motivational variables were assessed after a familiarization session, at 2 weeks, and at 4 weeks. Participants played the exergames M = 133.45 (SD = 81.27) minutes in week 1 to M = 77.23 (SD = 84.09) minutes in week 6. The two exergame conditions did not result in differences among theory of planned behavior variables (P > .05). Mean levels of these constructs declined across the first 4 weeks (P < .05), with the exception of injunctive norm. Positive bivariate associations (P < .05) between game play and perceived control (0-6 weeks), and intention (weeks 3-4 and weeks 5-6) were identified, but only affective attitude (assessed at week 2) predicted (P < .05) game play (3-4 weeks) in a multivariate examination of the theory of planned behavior model. The results demonstrate that social cognitive motives wane across time when exposed to repeated exergame play.

Direct referral and physical activity counselling upon discharge from spinal cord injury rehabilitation.

STUDY DESIGN: Sixteen-week follow-up study. OBJECTIVE: To evaluate the efficacy of referral from a health-care provider to regular exercise combined with 16 weeks of counselling support following discharge from inpatient or outpatient spinal cord injury (SCI) rehabilitation. SETTING: Two rehabilitation centres in Canada. METHODS: Seventeen participants (age 42.1±10.6 years, C3-T12, ASIA impairment score A-C) were recruited at discharge from inpatient (n=9; 5.2±1.3 months post-injury) or outpatient (n=8; 14.2±3.8 months post-injury) rehabilitation and were given a referral for regular exercise. Telephone counselling support was provided and adherence to the prescribed program was monitored for 16 weeks. RESULTS: There was a nonsignificant difference in exercise adherence rates (percentage of available sessions attended) between participants discharged from inpatient (71.4±44.9%) and those from outpatient (39.5±27.2%) rehabilitation programs. The most common barriers to participation were physical health problems (50%) and transportation (36%). An exercise beliefs questionnaire revealed that participants value exercise at discharge from rehabilitation, despite the common report of a relative lack of confidence in their ability to perform or adapt aerobic and resistance exercises to their specific capabilities. CONCLUSION: A system of direct referral and ongoing counselling support following discharge from either inpatient or outpatient SCI rehabilitation appears to encourage sustained participation, although future health promotion strategies should continue to provide specific information about how to adapt and complete aerobic and resistance exercises. SPONSORSHIP: Rick Hansen Institute and Ontario Neurotrauma Foundation.

Exercise equipment preferences among adults with spinal cord injury.

STUDY DESIGN: Cross-sectional. OBJECTIVES: To evaluate exercise equipment preferences and compare cardiometabolic demand for passive hybrid and arm-only exercise among adults with paraplegia (PP) and those with tetraplegia (TP). SETTING: Four community exercise programmes. METHODS: Thirty-six adults (mean age: 41.1±12.1 years) with chronic (11.4±10.7 years post injury) TP (C3-C8; n=17) or PP (T3-T12; n=19) were recruited. Participants completed 20 min of submaximal aerobic exercise at moderate to vigorous intensity on four types of aerobic exercise equipment: arm cycle ergometer (ACE), arm glider (AG), arm-leg recumbent stepper (ALRS), and arm-leg cycle ergometer (ALCE). Participants also completed 3 sets of 10 repetitions of resistance exercise using wall pulleys (WP) and weight stack (WS) equipment. A questionnaire was administered to evaluate equipment preference. Heart rate (HR) and oxygen uptake (VO2) were measured in a subset of participants (n=9) during submaximal aerobic exercise. RESULTS: Arm-only exercise modes were perceived as being safer than passive hybrid exercise modes. There were no differences in perceived enjoyment between equipment types and groups. There were significant group but not equipment differences in HR (TP: 101.4 bpm; PP: 124.9 bpm) and VO2 (TP: 6.5 ml•kg(-1)•min(-1); PP: 10.5 mL•kg(-1)•min(-1)) during submaximal aerobic exercise. CONCLUSION: In this cross-community assessment of exercise equipment preferences after spinal cord injury (SCI), arm-only exercise modes were perceived as safer than hybrid exercise modes and there were no differences between equipment types in physiological responses.

Temporal response of arterial stiffness to ultra-marathon.

The purpose of this investigation was to characterize the arterial stiffness of male ultra-marathon runners (n = 9) using pulse wave velocity (cfPWV) and radial tonometry over the course of an ultra-marathon and during recovery. Measures were collected at rest, immediately following 45 km/75 km of running, then following 60 and 90 min of recovery. No statistical difference was found between baseline cfPWV and normative values. The cfPWV of ultra-endurance runners decreased at 45 km (3.4 ± 1.6 m/s, p=0.006), followed by an increase (1.6 ± 1.8 m/s, p = 0.04) toward baseline levels at the 75 km mark. Radial tonometry measures also indicated small artery stiffness was transiently increased after 75 km. The amount of training time (r = 0.82, p = 0.007) and the duration of a typical training session (r = 0.73, p = 0.03) were correlated strongly with persisting decrements in large artery compliance at 60 min of recovery. The finding that arterial stiffness decreased at the 45 km distance and then reverted back toward baseline levels with prolonged running, may indicate a role of exercise duration or accumulated stress for affecting vascular compliance. At present, it is premature to suggest that athletes should alter training or racing practices to protect vascular health.

Effects of training status on arterial compliance in able-bodied persons and persons with spinal cord injury.

STUDY DESIGN: An investigation on large and small artery compliance in 36 able-bodied persons and persons with spinal cord injury (SCI). OBJECTIVE: To evaluate the effect of various training states (endurance-trained vs untrained) on arterial compliance in individuals with chronic SCI of traumatic origin and in able-bodied individuals (matched for age, sex, height, and weight). SETTING: Tertiary rehabilitation center in Canada. METHODS: Large and small artery compliance were measured at the radial artery and physical activity was assessed via questionnaire. RESULTS: There was no significant difference in large artery compliance between groups. Small artery compliance was reduced markedly (5.8±3.1 ml mm Hg(-1) × 100) in untrained persons with SCI, in comparison to all other groups. Small artery compliance of endurance-trained individuals with SCI was slightly (4%) higher than that observed in the untrained able-bodied individuals (8.6±1.5 vs. 8.2±1.4 ml mm Hg(-1) × 100, respectively). Endurance-trained, able-bodied persons had greater small artery compliance (10.6±2.3 ml mm Hg(-1) × 100) in comparison to the all other groups. CONCLUSION: Endurance training is related to increased small artery compliance in able-bodied individuals and persons with SCI (who are matched for age, sex, height and weight). Endurance training may attenuate the decline in small artery compliance seen with SCI.

Relative impact of neuromuscular and cardiovascular factors on bone strength index of the hemiparetic distal radius epiphysis among individuals with chronic stroke.

UNLABELLED: The objective of this study was to examine the associations of neuromuscular and cardiovascular impairments with the bone strength index of the hemiparetic distal radius epiphysis in chronic stroke survivors. The results showed that grip strength is the most predominant predictor of the bone strength index. INTRODUCTION: The purpose of the study was to examine the associations of neuromuscular and cardiovascular impairments with the bone strength index of the hemiparetic distal radius epiphysis in chronic stroke survivors. METHODS: Sixty-five chronic stroke survivors and 34 healthy control subjects underwent scanning of the distal radius epiphyseal site on both sides using peripheral quantitative computed tomography to measure trabecular volumetric bone mineral density (vBMD) (mg/cm(3)), total vBMD (mg/cm(3)), total area (mm(2)), and compressive bone strength index (cBSI) (g(2)/cm(4)). Various indicators of neuromuscular (grip strength, spasticity) and cardiovascular function (vascular elasticity, oxygen consumption during 6-min walk test) were evaluated. RESULTS: Analysis of variance revealed a significant main effect of side (p < 0.001) and group × side interaction (p < 0.05) for total BMC, total vBMD, trabecular vBMD, and cBSI (p < 0.05), with the stroke group showing greater side-to-side difference in these variables. However, no significant side-to-side difference in total area was detected in either group (p > 0.05). Sex-specific analysis yielded similar results. Multiple regression analyses revealed that the cBSI of the hemiparetic distal radius epiphysis had a stronger association with neuromuscular factors than cardiovascular factors. Overall, grip strength was the strongest determinant of the cBSI of the hemiparetic distal radius epiphysis (p < 0.01). CONCLUSIONS: Muscle weakness is the most predominant determinant of cBSI in the hemiparetic distal radius epiphysis among chronic stroke patients. Future studies should investigate the efficacy of different muscle-strengthening strategies in enhancing bone strength of this skeletal site in the chronic stroke population.

Comparing the Finapres and Caretaker systems for measuring pulse transit time before and after exercise.

We aimed to compare the Finapres system, which is designed for accurate intra-arterial amplitude measurement, to the Caretaker system, which is designed for temporal accuracy of intra-arterial measurement, in regard to measurement of pulse transit time (PTT) at baseline and following an endurance exercise session. Pulse transit time was evaluated between the R-wave of the ECG and the foot of the arterial waveform using either the Finapres (fpPTT) or Caretaker (ctPTT). 23 participants were measured before and after completion of endurance exercise. When comparing PTT values before and after an exercise intervention within devices, ctPTT was significantly different following exercise (P=0.03); however, the Finapres obtained values did not differ significantly. Before exercise, there was no significant relationship between devices, however, after exercise a significant moderate correlation was observed (r=0.45, P=0.02). Significant differences existed between ctPTT and fpPTT (P< 0.001). The Caretaker system appears to be more accurate at detecting changes in PTT occurring as a result of a single aerobic exercise session. This may be due to the servo-controller feedback loop in the waveform contour predicting algorithm within the Finapres system, which is not present in the Caretaker unit. The Finapres system also appears to have an inherent delay in pulse contour reporting.

Systemic arterial compliance following ultra-marathon.

There is a growing interest in training for and competing in race distances that exceed the marathon; however, little is known regarding the vascular effects of participation in such prolonged events, which last multiple consecutive hours. There exists some evidence that cardiovascular function may be impaired following extreme prolonged exercise, but at present, only cardiac function has been specifically examined following exposure to this nature of exercise. The primary purpose of this study was to characterize the acute effects of participation in an ultra-marathon on resting systemic arterial compliance. Arterial compliance and various resting cardiovascular indices were collected at rest from 26 healthy ultra-marathon competitors using applanation tonometry (HDI CR-2000) before and after participation in a mountain trail running foot race ranging from 120-195 km which required between 20-40 continuous hours (31.2±6.8 h) to complete. There was no significant change in small artery compliance from baseline to post race follow-up (8.5±3.4-7.7±8.2 mL/mmHgx100, p=0.65), but large artery compliance decreased from 16.1±4.4 to 13.5±3.8 mL/mmHgx10 (p=0.003). Participation in extreme endurance exercise of prolonged duration was associated with acute reductions in large artery compliance, but the time course of this effect remains to be elucidated.

A systematic review of exercise as a therapeutic intervention to improve arterial function in persons living with spinal cord injury.

STUDY DESIGN: All randomized controlled trials, prospective cohort, case-controlled, pre-post studies and case reports that assessed exercise interventions, which influence arterial structure and function after spinal cord injury (SCI), were included. OBJECTIVE: To review systematically the evidence for exercise as a therapy to alter arterial function in persons with SCI. SETTING: Literature searches were conducted for appropriate articles using several electronic databases (e.g. MEDLINE, EMBASE). METHODS: Three independent reviewers evaluated each investigation's quality, using the Physiotherapy Evidence Database Scale for randomized controlled trials and Downs and Black Scale for all other studies. Results were tabulated and levels of evidence assigned. RESULTS: A total of 283 studies were found through the systematic literature search. Upon review of the articles, 27 were included. The articles were separated into those investigating arterial benefits, resulting from either acute bouts of exercise or long-term exercise interventions. The ability of both acute and long-term exercise interventions to improve arterial structure and function in those with SCI was supported by limited to moderate methodological quality. Upper body wheeling is the most commonly examined exercise therapy for improving arterial function. It appears from the evidence that a variety of exercise interventions, including passive exercise, upper body wheeling, functional electrical stimulation and electrically stimulated resistance exercise, can improve arterial function in those living with SCI. CONCLUSIONS: Although the quality and volume of evidence is low, the literature supports exercise as a useful intervention technique for improving arterial function in those with SCI.

Challenges, concerns and common problems: physiological consequences of spinal cord injury and microgravity.

INTRODUCTION: Similarities between the clinical presentation of individuals living with spinal cord injury (SCI) and astronauts are remarkable, and may be of great interest to clinicians and scientists alike. OBJECTIVES: The primary purpose of this review is to outline the manner in which cardiovascular, musculoskeletal, renal, immune and sensory motor systems are affected by microgravity and SCI. METHODS: A comprehensive review of the literature was conducted (using PubMed) to evaluate the hallmark symptoms seen after spaceflight and SCI. This literature was then examined critically to determine symptoms common to both populations. RESULTS: Both SCI and prolonged microgravity exposure are associated with marked deteriorations in various physiological functions. Atrophy in muscle and bone, cardiovascular disturbances, and alterations in renal, immune and sensory motor systems are conditions commonly observed not only in individuals with SCI, but also in those who experience prolonged gravity unloading. CONCLUSION: The preponderance of data indicates that similar physiological changes occur in both SCI and prolonged space flight. These findings have important implications for future research in SCI and prolonged space flight.

The development of evidence-informed physical activity guidelines for adults with spinal cord injury.

OBJECTIVES: To systematically develop evidence-informed physical activity guidelines to improve physical fitness in people with spinal cord injury (SCI). SETTING: This study was conducted in Canada. METHODS: The Appraisal of Guidelines, Research and Evaluation II guideline development protocol was used to develop exercise guidelines to improve physical capacity and muscular strength. The evidence base for the guideline development process consisted of a systematic review and quality appraisal of research examining the effects of exercise on physical fitness among people with SCI. A multidisciplinary expert panel deliberated the evidence and generated the guidelines. Pilot testing led to refinement of the wording and presentation of the guidelines. RESULTS: The expert panel generated the following guidelines: for important fitness benefits, adults with a SCI should engage in (a) at least 20 min of moderate to vigorous intensity aerobic activity two times per week and (b) strength training exercises two times per week, consisting of three sets of 8-10 repetitions of each exercise for each major muscle group. CONCLUSION: People with SCI, clinicians, researchers and fitness programmers are encouraged to adopt these rigorously developed guidelines.

The challenge of low physical activity during the school day: at recess, lunch and in physical education.

PURPOSE: To describe physical activity (PA) intensity across a school day and assess the percentage of girls and boys achieving recommended guidelines. METHODS: The authors measured PA via accelerometry in 380 children (8-11 years) and examined data representing (1) the whole school day, (2) regular class time, (3) recess, (4) lunch and (5) scheduled physical education (PE). Activity was categorised as sedentary (SED), light physical activity (LPA) or moderate to vigorous physical activity (MVPA) using age-specific thresholds. They examined sex differences across PA intensities during each time period and compliance with recommended guidelines. RESULTS: Girls accumulated less MVPA and more SED than boys throughout the school day (MVPA -10.6 min; SED +13.9 min) recess (MVPA -1.6 min; SED +1.7 min) and lunch (MVPA -3.1 min; SED +2.9 min). Girls accumulated less MVPA (-6.2 min), less LPA (-2.5 min) and more SED (+9.4 min) than boys during regular class time. Fewer girls than boys achieved PA guidelines during school (90.9% vs 96.2%), recess (15.7% vs 34.1%) and lunch (16.7% vs 37.4%). During PE, only 1.8% of girls and 2.9% of boys achieved the PA guidelines. Girls and boys accumulated similar amounts of MVPA, LPA and SED. CONCLUSION: The MVPA deficit in girls was due to their sedentary behaviour as opposed to LPA. Physical activity strategies that target girls are essential to overcome this deficit. Only a very small percentage of children met physical activity guidelines during PE. There is a great need for additional training and emphasis on PA during PE. In addition schools should complement PE with PA models that increase PA opportunities across the school day.

An active school model to promote physical activity in elementary schools: action schools! BC.

OBJECTIVE: To assess the impact of an active school model on children's physical activity (PA). DESIGN: 16-month cluster randomised controlled trial. SETTING: 10 elementary schools in Greater Vancouver, BC. PARTICIPANTS: 515 children aged 9-11 years. INTERVENTION: Action Schools! BC (AS! BC) is an active school model that provided schools with training and resources to increase children's PA. Schools implemented AS! BC with support from either external liaisons (liaison schools, LS; four schools) or internal champions (champion schools, CS; three schools). Outcomes were compared with usual practice (UP) schools (three schools). MAIN OUTCOME MEASUREMENTS: PA was measured four times during the study using pedometers (step count, steps/day). RESULTS: Boys in the LS group took 1175 more steps per day, on average, than boys in the UP group (95% CI: 97 to 2253). Boys in the CS group also tended to have a higher step count than boys in the UP group (+804 steps/day; 95% CI: -341 to 1949). There was no difference in girls' step counts across groups. CONCLUSIONS: The positive effect of the AS! BC model on boys' PA is important in light of the current global trend of decreased PA.

Hippocampal volume and vasculature before and after exercise in treatment-resistant schizophrenia.

BACKGROUND: Schizophrenia is associated with poor cognitive function and elevated cardiometabolic disease risk. These health concerns may exacerbate neurocognitive dysfunction associated with hippocampal abnormalities, particularly hippocampal volume reductions. Regular exercise is thought to improve symptom severity, reduce depression, and improve cognition in schizophrenia, and may trigger exercise-mediated hippocampal growth. The potential for the benefits of exercise for treatment-resistant schizophrenia patients has not been clearly assessed. This study aims to assess the effect of exercise on hippocampal plasticity and clinical outcomes in chronic schizophrenia. METHODS: Seventeen DSM-IV criteria schizophrenia or schizoaffective disorder patients completed a customized moderate intensity 12-week aerobic or weight-bearing exercise program. Adherence rates were 83% ±â€¯9.4%) with 70% of participants completing the entire exercise program. Concomitant neuroimaging, clinical and cognitive assessments were obtained at baseline and 12-weeks. RESULTS: At follow-up, symptom severity scores (t(16) = -16.8, p. ≤ 0.0001) and social functioning (t(16) = 4.4, p. = 0.0004) improved. A trend for improved depression scores (t(16) = -2.0, p. = 0.06) with no change in anxiety, or extrapyramidal symptoms were seen. Hippocampal volume increased (t(16) = -2.54, p. = 0.02), specifically in the left CA-1 field (F(16) = -2.33, p. = 0.03). Hippocampal vascular volume was unchanged. Change in hippocampal volume and vascular volume was not significantly correlated with change in symptom severity or affect scores. CONCLUSIONS: Adjunct exercise may accelerate symptom improvement in treatment-resistant psychosis patients. While the underlying mechanism remains unclear, these results indicate that chronic schizophrenia patients experience hippocampal plasticity in response to exercise. STUDY REGISTRATION: Clinical Trials.govNCT01392885.

A prediction model for estimating pulmonary oxygen uptake during the 6-minute walk test in organ transplant recipients.

We developed a multivariate prediction equation for estimating the highest obtainable pulmonary oxygen uptake (VO2p) during the 6-minute walk test (6-MWT) in 54 organ transplant recipients: heart/heart-double-lung (n=14), kidney/kidney-pancreas (n=16), liver (n=14), double lung (n=8), bone marrow (n=2). They were of age, 48+/-12 years. Participants performed a 6-MWT during which expired gases were collected and analyzed with a portable metabolic system interfaced with a wireless heart rate monitor. The following variables significantly contributed to the model for predicting the highest obtainable 6-MWT VO2p: 6-MWT distance (m), age (years), gender (male=0, female=1), resting heart rate, peak heart rate, weight (kg), and transplant type (kidney/kidney-pancreas=1, other=0), where: VO2p=1.253+0.022 (6-MWT distance)+0.112 (age) -3.192 (gender) -0.104 (resting heart rate)+0.127 (peak 6-MWT heart rate)-0.084 (weight)+2.116 (transplant type). The explanatory variables in our final model accounted for 78% of the variance in 6-MWT VO2p. In conclusion, the addition of an easily estimated 6-MWT VO2p will provide added clinical information of functional capacity following an exercise rehabilitation intervention or during routine follow-up for organ transplant recipients.

A systematic review and meta-analysis of exercise and exercise hypertension in patients with aortic coarctation.

Exercise hypertension is a common occurrence among individuals with aortic coarctation. Although exercise is known to be beneficial among the general population, the risks and benefits of exercise among those with aortic coarctation are less clear. This systematic review evaluates the benefits and risks of exercise for persons with aortic coarctation. Electronic databases were systematically searched (that is, MEDLINE and EMBASE) and key reviews cross-referenced to identify articles for inclusion. Original research articles reporting exercise among individuals with aortic coarctation were included. From 2608 individual citations, 68 eligible articles were identified. Aerobic exercise stress tests were found to be useful for determining exercise hypertension experiences post-surgical repair (N=5), and other long-term secondary findings (N=3). Experiences of exercise hypertension were associated with abnormal cardiac and/or aortic geometry and cardiac function (N=7). Exercise capacity was generally found to be similar to non-aortic coarctation controls post surgery (N=6). Exercise hypertension was experienced by 27% of participants, including 10% of adults and 43% of children/youth. Individuals who experience exercise hypertension experience greater increases in systolic blood pressure with exercise. No investigations identified evaluated forms of exercise other than aerobic stress tests and no exercise training programs have been conducted to date. Exercise stress tests can be valuable in this population for determining exercise hypertension, especially in the year post-surgical repair. Additional research is urgently needed to accurately assess the benefits and risks of exercise and exercise hypertension, and applicability of exercise restrictions for this population.

Protective effects of acute exercise prior to doxorubicin on cardiac function of breast cancer patients: A proof-of-concept RCT.

BACKGROUND: Preclinical studies have reported that a single treadmill session performed 24h prior to doxorubicin provides cardio-protection. We aimed to characterize the acute change in cardiac function following an initial doxorubicin treatment in humans and determine whether an exercise session performed 24h prior to treatment changes this response. METHODS: Breast cancer patients were randomized to either 30min of vigorous-intensity exercise 24h prior to the first doxorubicin treatment (n=13), or no vigorous exercise for 72h prior to treatment (control, n=11). Echocardiographically-derived left ventricular volumes, longitudinal strain, twist, E/A ratio, and circulating NT-proBNP, a marker of later cardiotoxicity, were measured before and 24-48h after the treatment. RESULTS: Following treatment in the control group, NT-proBNP, end-diastolic and stroke volumes, cardiac output, E/A ratio, strain, diastolic strain rate, twist, and untwist velocity significantly increased (all p≤0.01). Whereas systemic vascular resistance (p<0.01) decreased, and ejection fraction (p=0.02) and systolic strain rate (p<0.01) increased in the exercise group only. Relative to control, the exercise group had a significantly lower NT-proBNP (p<0.01) and a 46% risk reduction of exceeding the cut-point used to exclude acute heart failure. CONCLUSION: The first doxorubicin treatment is associated with acutely increased NT-proBNP, echocardiographic parameters of myocardial relaxation, left ventricular volume overload, and changes in longitudinal strain and twist opposite in direction to documented longer-term changes. An exercise session performed 24h prior to treatment attenuated NT-proBNP release and increased systolic function. Future investigations should verify these findings in a larger cohort and across multiple courses of doxorubicin.

The vascular health status of a population of adult Canadian Indigenous peoples from British Columbia.

Indigenous populations currently experience greater cardiovascular disease burdens. However, subclinical vascular structure and function among these populations is not well known. This investigation evaluated vascular structure and function among Canadian Indigenous populations. Blood pressure, body composition, pulse-wave velocity (PWV), baroreceptor sensitivity (BRS), arterial compliance and intima-media thickness (IMT) were measured. Vascular measures were evaluated across sexes and age groups. Vascular assessments were conducted among 55 Indigenous adults (38±18 years, 29 Female), including both First Nations (N=36) and Métis (N=19) individuals. Some differences in vascular measures were found between males and females, respectively (spectral BRS: 9.6±6.8 ms mm Hg(-1) vs 16.9±10.0 ms mm Hg(-1), P=0.01; small arterial compliance: 8.9±3.7 ml mm Hg(-1) × 100 vs 6.4±2.3 ml mm Hg(-1) × 100, P=0.004), with similar measures of overall IMT (0.61±0.14 mm vs 0.57±0.08 mm, P=0.19) and central PWV (5.7±2.5 m s(-1) vs 5.1±2.3 m s(-1), P=0.58). Greater IMT, and lower BRS and arterial compliance were identified among older adults. This relatively healthy population demonstrated healthy vascular measures, with poorer measures among older individuals.

Reliability and validity of measures of cardiac output during incremental to maximal aerobic exercise. Part II: Novel techniques and new advances.

For exercise physiologists and sport cardiologists, one of the greatest challenges is to develop a valid, reliable, noninvasive and affordable measure of cardiac output (Q). There are several techniques available to measure Q during exercise conditions. These procedures generally provide accurate and reliable determinations of Q during submaximal exercise, but may be limited during maximal exercise conditions. The most commonly used noninvasive measures are the acetylene (C2H2) and carbon dioxide (CO2) rebreathe methods as reviewed in part I of this article. Only the foreign gas rebreathe method, using C2H2, meets all of the criteria of being noninvasive, easy to use, reliable and valid for use during maximal exercise. New methodologies have recently been developed to measure Q during exercise conditions. Although not as popular as the C2H2 and CO2 rebreathe methods, these methods have increasingly gained favour in exercise physiology and sport cardiology settings. The majority of these measures (if performed meticulously), with the exception of impedance cardiography, provide reasonably accurate and reliable determinations of Q. However, the cost of usage and technological limitations during maximal exercise have prevented these techniques from replacing the conventional measures of Q during exercise conditions. Doppler echocardiography and the modified C2H2 methods hold promise for the assessment of Q during maximal exercise. With further advances in these technologies their use in exercise physiology and sport cardiology setting may become more common.

Reliability and validity of measures of cardiac output during incremental to maximal aerobic exercise. Part I: Conventional techniques.

The assessment of cardiac function, particularly cardiac output (Q) during heavy exercise is essential for the evaluation of cardiovascular factors that might limit oxygen transport. A series of invasive and noninvasive techniques has been developed for the assessment and monitoring of Q during resting and submaximal exercise conditions. However, very few techniques have been found to give accurate and reliable determinations of Q during vigorous to maximum exercise. For exercise physiologists and sport cardiologists, maximal exercise data are of primary importance. The 'gold standard' measures of cardiac function are considered to be the direct Fick and dye-dilution methods. These have been widely shown to give accurate and reliable determinations of Q during resting and submaximal exercise conditions; however, their use during maximal exercise conditions is debatable due to the inherent risks involved with each and their increasing inaccuracy during the later stages of vigorous exercise. Thermodilution has also been considered to be a relatively good method for the determination of Q during rest and exercise conditions, but recent authors have questioned its use due to the nature of the measure and its inaccuracy during strenuous exercise. Various noninvasive measures of cardiac function have been developed to overcome the problems associated with the 'gold standard' measures. The first part of this article discusses conventional techniques used in exercise physiology settings. The majority of these provide accurate and reliable determinations of Q during rest and submaximal exercise. However, very few techniques are suitable for maximal exercise conditions. Perhaps only the foreign gas rebreathe using acetylene (C2H2) meets all the criteria of being noninvasive, simple to use, reliable over repeated measurements, accurate and useful during maximal exercise.