Performing the exercise test

Analysis of Blood Pressure and Ventilation Efficiency in Different Types of Obesity Aged 40-60 Years by Cardiopulmonary Exercise Test

PURPOSE

This study investigated blood pressure and ventilation efficiency by cardiopulmonary exercise test (CPX) in different types of obesity aged 40-60 years.

MATERIAL AND METHODS

The inclusion criteria of this cross-sectional study were adults aged 40-60 years underwent health checks. CPX was measured according to the relevant standards. According to different body mass index (BMI), there were 3 groups, BMI<24 (kg/m²), 24≤BMI<28 (kg/m²) and BMI≥28 (kg/m²). There were two groups in male, waist circumference≥90 (cm) and waist circumference<90 (cm). Similarly, there were two groups in female, waist circumference≥85 (cm) and waist circumference<85 (cm).

RESULTS

There were 543 individuals (64.6% male and 35.4% female) aged 40-60 years in this study. The resting blood pressure (BP) and peak BP have the significant differences in different BMI groups (p < 0.001) and male or female groups (p < 0.001). However, the resting DBP (77.70±9.45 vs 81.16±8.80, p < 0.001) and peak DBP (85.67±10.21 vs 89.03±9.94, p = 0.002) have the significant differences in different male waist circumference groups, and the resting BP (SBP 113.76±14.29 vs 121.86±15.54, p = 0.001, DBP 71.95±10.83 vs 77.27±11.42, p = 0.005) has the significant differences in different female waist circumference groups. Carbon dioxide Ventilation equivalent (VE/VCO₂) has the significant differences in different male waist circumference groups (26.84±3.10 vs 27.68±2.93, p = 0.009), but it has not the significant differences in different BMI groups and different female waist circumference groups. The oxygen pulse (VO₂/HR) is slightly higher in female group than male group (0.93±0.15 vs 0.89±0.15, p = 0.001). Breathing reserve has the statistical significance in BMI ≥28 group compared with the BMI <24 group (0.52±0.13 vs 0.46±0.17, ηp²=0.021).

CONCLUSION

We found that the blood pressure and ventilation efficiency of CPX were different between the obesity and normal. This will provide a basis for accurate cardiopulmonary assessment of obesity.

Exercise right heart catheterization predicts outcome in asymptomatic degenerative aortic stenosis

INTRODUCTION AND OBJECTIVES

Degenerative aortic stenosis (DAS) is the most frequent valvular heart disease. It remains unclear how to identify asymptomatic DAS patients with normal left ventricular ejection fraction who have a high probability of event occurrence and would thus benefit from early intervention. Here, we describe a protocol for exercise hemodynamics in true asymptomatic patients with moderate or severe DAS and assess the prognostic value of the data obtained in this population.

METHODS

This study involved a prospective single-centre registry of consecutive asymptomatic patients with moderate or severe DAS. Patients underwent cardiopulmonary exercise testing to confirm symptom absence during exercise and then right heart catheterization (RHC) at rest and during exercise. Events were defined as death, surgical aortic valve replacement, or transcatheter aortic valve implantation according to clinical guidelines.

RESULTS

Thirty-three patients underwent baseline and exercise RHC. The mean aortic valve area was 1.08 cm² and the aortic gradient was 39mmHg. The mean pulmonary artery pressure was 21mmHg with a pulmonary artery occlusion pressure of 14mmHg and cardiac output of 5.6 L/min. The mean pulmonary artery pressure at peak exercise was 34mmHg. After a mean follow-up of 27 months, 8 patients experienced an event (24%). There were no differences in baseline variables, aortic valve area, or cardiopulmonary exercise testing parameters between the event and event-free groups. Patients with an event did not have higher pulmonary or filling pressures after peak exercise but had lower pulmonary artery oxygen saturation on effort (median, 48% vs 57%, P=.03).

CONCLUSIONS

Exercise RHC is feasible and safe in this population. Peak pulmonary artery oxygen saturation might identify patients with increased risk of serious adverse events.

APOEε4 impacts up-regulation of brain-derived neurotrophic factor after a six-month stretch and aerobic exercise intervention in mild cognitively impaired elderly African Americans: A pilot study

Possession of the Apolipoprotein E (APOE) gene ε4 allele is the most prevalent genetic risk factor for late onset Alzheimer's disease (AD). Recent evidence suggests that APOE genotype differentially affects the expression of brain-derived neurotrophic factor (BDNF). Notably, aerobic exercise-induced upregulation of BDNF is well documented; and exercise has been shown to improve cognitive function. As BDNF is known for its role in neuroplasticity and survival, its upregulation is a proposed mechanism for the neuroprotective effects of physical exercise. In this pilot study designed to analyze exercise-induced BDNF upregulation in an understudied population, we examined the effects of APOEε4 (ε4) carrier status on changes in BDNF expression after a standardized exercise program. African Americans, age 55years and older, diagnosed with mild cognitive impairment participated in a six-month, supervised program of either stretch (control treatment) or aerobic (experimental treatment) exercise. An exercise-induced increase in VO₂Max was detected only in male participants. BDNF levels in serum were measured using ELISA. Age, screening MMSE scores and baseline measures of BMI, VO₂Max, and BDNF did not differ between ε4 carriers and non-ε4 carriers. A significant association between ε4 status and serum BDNF levels was detected. Non-ε4 carriers showed a significant increase in BDNF levels at the 6month time point while ε4 carriers did not. We believe we have identified a relationship between the ε4 allele and BDNF response to physiologic adaptation which likely impacts the extent of neuroprotective benefit gained from engagement in physical exercise. Replication of our results with inclusion of diverse racial cohorts, and a no-exercise control group will be necessary to determine the scope of this association in the general population.

A standardized randomized 6-month aerobic exercise-training down-regulated pro-inflammatory genes, but up-regulated anti-inflammatory, neuron survival and axon growth-related genes

There is considerable support for the view that aerobic exercise may confer cognitive benefits to mild cognitively impaired elderly persons. However, the biological mechanisms mediating these effects are not entirely clear. As a preliminary step towards informing this gap in knowledge, we enrolled older adults confirmed to have mild cognitive impairment (MCI) in a 6-month exercise program. Male and female subjects were randomized into a 6-month program of either aerobic or stretch (control) exercise. Data collected from the first 10 completers, aerobic exercise (n=5) or stretch (control) exercise (n=5), were used to determine intervention-induced changes in the global gene expression profiles of the aerobic and stretch groups. Using microarray, we identified genes with altered expression (relative to baseline values) in response to the 6-month exercise intervention. Genes whose expression were altered by at least two-fold, and met the p-value cutoff of 0.01 were inputted into the Ingenuity Pathway Knowledge Base Library to generate gene-interaction networks. After a 6-month aerobic exercise-training, genes promoting inflammation became down-regulated, whereas genes having anti-inflammatory properties and those modulating immune function or promoting neuron survival and axon growth, became up-regulated (all fold change≥±2.0, p<0.01). These changes were not observed in the stretch group. Importantly, the differences in the expression profiles correlated with significant improvement in maximal oxygen uptake (VO2max) in the aerobic program as opposed to the stretch group. We conclude that three distinct cellular pathways may collectively influence the training effects of aerobic exercise in MCI subjects. We plan to confirm these effects using rt-PCR and correlate such changes with the cognitive phenotype.

Lack of Association Between ACE Indel Polymorphism and Cardiorespiratory Fitness in Physically Active and Sedentary Young Women

Background:

Polymorphisms at the angiotensin-converting enzyme gene (ACE), such as the indel [rs1799752] variant in intron 16, have been shown to be associated with aerobic performance of athletes and non-athletes. However, the relationship between ACE indel polymorphism and cardiorespiratory fitness has not been always demonstrated.

Objectives:

The relationship between ACE indel polymorphism and cardiorespiratory fitness was investigated in a sample of young Caucasian Brazilian women.

Patients and Methods:

This study investigated 117 healthy women (aged 18 to 30 years) who were grouped as physically active (n = 59) or sedentary (n = 58). All subjects performed an incremental exercise test (ramp protocol) on a cycle-ergometer with 20-25 W/min increments. Blood samples were obtained for DNA extraction and to analyze metabolic and hormonal profiles. ACE indel polymorphism was determined by polymerase chain reaction (PCR) and fragment size analysis.

Results:

The physically active group had higher values of peak oxygen uptake (VO₂ peak), carbon dioxide output (VCO₂), ventilation (VE) and power output than the sedentary group (P < 0.05) at the peak of the exercise test. However, heart rate (HR), systolic blood pressure (SBP) and diastolic blood pressure (DBP) did not differ between groups. There was no relationship between ACE indel polymorphism and cardiorespiratory variables during the test in both the physically active and sedentary groups, even when the dominant (DD vs. D1 + 2) and recessive (2 vs. DI + DD) models of inheritance were tested.

Conclusions:

These results do not support the concept that the genetic variation at the ACE locus contributes to the cardiorespiratory responses at the peak of exercise test in physically active or sedentary healthy women. This indicates that other factors might mediate these responses, including the physical training level of the women.

Long-term mortality with multiple treadmill exercise test abnormalities: comparison between patients with and without cardiovascular disease

BACKGROUND

Poor exercise capacity, abnormal heart rate responses, and electrocardiographic abnormalities during treadmill exercise testing independently predict mortality. The combined relationship of these 3 variables to determine the incremental increase in mortality was compared in groups with and without known cardiovascular disease (CVD).

METHODS

Patients referred for treadmill exercise testing during 1986 to 1991 were included. Exercise capacity <74% (of age- and gender-predicted value), heart rate reserve of <68 beat/min, and horizontal or down-sloping ST depression of > or =1 mm were considered abnormal. Cox proportional hazards regression was used to determine all-cause mortality (average follow-up of 16 years) based on the number of exercise test abnormalities (0, 1, 2, or all 3).

RESULTS

Among 10,897 patients, 20.9% (n = 2,277) had CVD. Poor exercise capacity and limited heart rate reserve were associated with increased risk of mortality (P < .0001) in both groups; however, abnormal exercise electrocardiogram was associated with an increased risk of mortality in the no-CVD group only (P < .0001). A graded increase in mortality was observed with increase in number of abnormal exercise test results in both groups. Patients without CVD having 2 or 3 abnormal exercise test results had a similar age-adjusted risk of long-term mortality as those with CVD but normal exercise test results, with a hazard ratio comparing these groups = 1.01 (95% CI 0.79-1.28).

CONCLUSIONS

The combinatorial approach validates the prognostic significance of multiple exercise test variables. The presence of > or =2 exercise test abnormalities may constitute a "CVD risk equivalent" in patients without CVD.

Do subsidization and monitoring enhance adherence to prescribed exercise?

PURPOSE

We studied whether partial versus full subsidization and self versus other monitoring promote adherence to physician-prescribed exercise.

METHOD

We randomly assigned 132 participants to experimental conditions defined by two levels of subsidization and two types of monitoring. Physicians wrote prescriptions as referrals to an exercise facility. A computer recorded participants' exercise for 12 weeks. A sponsoring medical organization paid half or all of the facility's fees. Half of the participants kept records of workouts, and half reported workouts to researchers who telephoned them.

RESULTS

Fully subsidized patients averaged 21.41 workouts versus 16.67 workouts by partially subsidized patients (p < .05). Researcher-monitored participants averaged 22.14 workouts versus 15.96 workouts by self-monitored participants (p < .01).

CONCLUSIONS

Full subsidization and third-party monitoring increased exercise rates. These findings encourage use of both to enhance prescribed exercise rates and continued study of factors that contribute to the efficacy of prescribed exercise.

Impact of fatness, fitness, and ethnicity on the relationship of nocturnal ghrelin to 24-hour luteinizing hormone concentrations in adolescent girls

CONTEXT

Ghrelin is related to energy balance that regulates food intake.

OBJECTIVE

The aim was to explore whether ghrelin would be linked to differences in fitness in adolescent girls, whose menstrual cycles are sensitive to changes in energy balance.

METHODS

A total of 72 girls, ages 14-21 yr, including five with amenorrhea, were studied in the follicular phase. LH was sampled every 10 min over 24-h, and ghrelin was measured hourly between 2300 and 0300 h. Body composition was measured by dual x-ray absorptiometry. Fitness was characterized by reported frequency of exercise per week and by maximal oxygen consumption with "high" vs. "low" fitness groups defined from maximal oxygen consumption norms for this population. Data were analyzed with SAS software (SAS Institute Inc., Cary, NC).

RESULTS

Ghrelin was related to percent body fat (P = 0.038; R(2) 0.07), weekly exercise (P = 0.032; R(2) 0.07), and 24-h mean LH (P = 0.002; R(2) 0.13). The ghrelin relationship with LH was more pronounced in the low-fitness group. In multiple regression models, 24-h LH was an independent predictor of ghrelin after adjusting for percent body fat, fitness, exercise, or age. Ghrelin was higher in Caucasian girls than in African-American girls after adjusting for covariates at 0200 h (P = 0.017).

CONCLUSIONS

Twenty-four-hour LH is an independent predictor of nighttime ghrelin concentrations in postpubertal adolescent girls. Diverging patterns in ghrelin may reflect differences in exercise patterns and/or may be influenced by ethnicity. These data introduce ghrelin as a biomarker of individual differences in energy balance during the menstrual cycle and across ethnicities.

Twenty-four hour growth hormone and leptin secretion in active postpubertal adolescent girls: impact of fitness, fatness, and age at menarche

CONTEXT

GH is strongly related to body composition, physical activity, and pubertal progression. Adolescent girls decrease physical activity during puberty, whereas their weight increases. Because leptin is a good index of energy balance in active young women, we hypothesized that leptin is related to GH secretion in this population while taking into account fitness, fatness, and age at menarche.

METHODS

We measured body composition and maximal oxygen consumption (VO(2)max) in 37 postpubertal adolescent girls aged 16-21 yr. GH was sampled every 10 min and leptin hourly for 24 h. We first analyzed 6-h time blocks by repeated measures for GH and leptin, with body mass index (BMI), percent body fat, and VO(2)max as covariates for the entire group and a lean subgroup. The deconvolution method was used to characterize GH pulsatility from individual time points.

RESULTS

GH varied through the day (P < 0.0001), with the highest concentrations overnight. BMI, percent body fat, and VO(2)max were related to GH concentrations in the entire group, whereas leptin predicted GH in the entire group as well as the lean subgroup of girls. Higher leptin was related to lower GH concentrations (P = 0.011), regardless of time. A log leptin level increase by 1 unit decreased GH by 27%. Pulsatility characteristics showed a 1-yr increase of age at menarche increasing total GH input by 20% (P = 0.0035) independently from BMI.

CONCLUSION

In postpubertal adolescent girls, leptin is related to GH concentration across the lean to overweight BMI spectrum. GH pulsatile secretion was greater in girls with later age at menarche.

Exercise treadmill test may predict clinical outcome among working-aged patients suspected of coronary heart disease in general practice

OBJECTIVE

To specify the diagnostic value of treadmill tests conducted in primary health care by trained GPs for working-aged patients.

DESIGN

A two-year follow-up study.

SETTING

Kangasala Health Centre, Finland.

SUBJECTS

All patients under the age of 60 (n = 348) examined by exercise treadmill test carried out by trained GPs during a period of three years.

MAIN OUTCOME MEASURES

The number of patients having a diagnosis of coronary heart disease at the end of two years' follow-up. Predictive values of the exercise test.

RESULTS

During the two years' follow-up period CHD was diagnosed in six of the patients who did not yield a positive finding in the test. A negative finding in the test was very reliable; coronary heart disease manifested in only 2% of these cases. Almost half of the patients yielding a positive finding ended up having coronary angiography and 1 in 10 underwent coronary bypass surgery.

CONCLUSION

Among working-aged patients suspected of coronary heart disease an exercise treadmill test may predict clinical outcome in general practice.

Maximal Aerobic Capacity Testing of Older Adults: A Critical Review

Most of the data that describe maximal oxygen uptake (VO(2max)) and the requirements for its attainment have been developed using young adults as subjects. Many older adults are unable to satisfactorily complete a maximal exercise effort in a standard exercise stress test. This review describes exercise tests currently available to measure VO(2max) in older adults. PubMed and CINAHL databases were searched for studies including healthy individuals older than 65 years with reproducible descriptions of the testing protocol. The research on VO(2max) testing in healthy individuals older than 65 years is limited, does not describe the protocols in detail, and/or lacks information on the psychometric properties of the exercise tests. There is a need for refinement of the few existing protocols for testing aerobic capacity in older adults, as well as the development of new protocols specifically applicable to older adults. Consensus on the criteria defining VO(2max) attainment during exercise in older adults is required, as well as agreement on the most appropriate exercise protocols and equipment, specific to older adults, to successfully fulfil these criteria.