Factors defining oxygen uptake at peak exercise in aged people
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Abstract:
Maximum oxygen uptake (VO2max) is defined as the highest rates at which oxygen can be taken up and utilized by the body during severe exercise indicating the cardiopulmonary fitness of the individual. It is one of the main variables in the field of exercise physiology and is frequently used to indicate the cardio-respiratory fitness of an individual [1]. Consequently, there has been great interest in identifying the physiological factors that limit VO2max and determining the role of this variable in endurance and anaerobic performances. Today, it is universally accepted that there is a physiological upper limit to the body's ability to consume oxygen. In the scientific literature, an increase in VO2max is the most common method of demonstrating a training effect. In addition, VO2max is frequently used in the development of an exercise prescription in health and disease. Given these applications of VO2max, there has been great interest in identifying the physiological factors that limit VO2max and determining the role of this variable in endurance performance. Aging-related changes occur mainly in the cardiopulmonary and skeletal muscles, bringing about a reduction in physical performance [7]. Such myocardial and peripheral functional changes include a decline in the maximum heart rate, stroke volume, and contractility, and an increase in peripheral vascular resistance. Consequently, the maximal VO2max decreases. The primary aging process, itself genetically associated, occurs both independently of lifestyle and in the absence of disease [4]. Accordingly, one may expect maximal cardiac output to decrease with aging irrespective of lifestyle because of genetic factors. Reduced arteriovenous oxygen difference at maximal effort [6] is the second factor associated with decrease with aging of VO2max. Incremental exercise is characterized by exposing the subjects to a high degree of load which may alter the left ventricular contractility and function [5]. This has the effect of placing a large load on the left ventricular which might have significant effects on oxygen delivery to the working muscles. Thus, oxygen delivery to the working muscle may be reduced, and since metabolic demand during incremental exercise is increased over time to maximum, elderly subjects may maintain the energy supply due to the balance between O2 delivery and extraction. Untrained and trained elderly can increase the response of the central factors i.e., cardiopulmonary without a significant reduction in peripheral ability to extract oxygen at the muscle level. It was found that in elderly subjects, skeletal muscle mitochondrial capacity, tissue blood flow capacity, and oxygen exchange capacity appear to be wellmatched. It seems that intrinsic mitochondrial function and regulation are not altered significantly. Values for cardiac output at peak aerobic exercise are low in the untrained compared to the trained at maximal aerobic exercise. The lower cardiac output in the untrained elderly at peak exercise is related to the limited heart rate reserve, stroke volume, contractility, and to the inappropriate adjustment of the circulation [3, 5]. The augmentation in maximal oxygen uptake in the trained elderly in response to M. Sagiv (*) :D. Ben-Sira : R. Amir Sports Medicine and Rehabilitation Division, Zinman College of Physical Education and Sport Sciences Wingate, Netany, Israel 42902 e-mail: sagiv-moran@wincol.ac.ilKeywords:
Endurance Training
Exercise prescription
Contractility
Background: Cardio respiratory fitness in terms of maximum oxygen uptake (VO2 max) reflects the physical fitness of a person. VO2max determines the capacity of an individual to perform sustained exercise. The present study is to assess and compare the cardiorespiratory fitness in terms of VO2 max between trained and untrained subjects.
Materials and Methods: This cross-sectional study was conducted on 30 young adult males undergoing physical training for more than 3 months to join British army and age-sex matched 30 non-trained controls. VO2max was estimated indirectly by following the protocol of Queen’s College Step Test (QCT) method.
Results: VO₂ max was found significantly higher in the trained males as compared to non-trained group (68.91± 4.42 vs. 50.31±4.80; p=0.02). On comparison of VO₂ max of our subjects with the standard VO₂ max classification, our trained and non-trained groups fitted into the category of high and average on cardiorespiratory fitness scale respectively.
Conclusion: Physical training improves cardio respiratory fitness by increasing VO₂ max.
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Climacteric
Bicycle ergometer
Aerobic Exercise
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Lack of cardiorespiratory fitness may well contribute to the increasing prevalence of degenerative cardiovascular disease throughout the world. As a first step towards co-ordinated and internationally comparable investigation of this problem, methods of measuring the reference standard of cardiorespiratory fitness-the maximum oxygen intake, (Vo(2))(max)-were compared by an international working party that met in Toronto in the summer of 1967.Repeated testing of 24 subjects showed that the (Vo(2))(max) was greatest on the treadmill, 3.4% smaller in a stepping test, and 6.6% smaller during use of a bicycle ergometer. There were also parallel differences in cardiac stroke volume. Uphill treadmill running was recommended for the laboratory measurement of (Vo(2))(max), and stepping or bicycle exercise for field studies. A discontinuous series of maximum tests caused some improvement in the fitness of subjects, and a "continuous" test (with small increases in load at 2-min intervals) was preferred.
Treadmill
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Better understanding the impact of changes in physical activity levels on cardiorespiratory fitness, as measured by maximal oxygen uptake (VO(2max)) may inform preventive interventions. We aimed to determine longitudinal changes in physical activity levels over 5 years and the relationship between these changes with VO(2max) in a sample of Chinese midlife women.A total of 184 Chinese women aged 50-64 years in Hong Kong were enrolled for this study. Physical activity was assessed with the modified Chinese Baecke questionnaire at baseline (2002-2004) and follow-up (2008-2009). VO(2max) was measured with a symptom-limited maximal exercise test on an electrically braked cycle ergometer at follow-up.Compared with subjects who were persistently inactive, those who were increasingly/persistently active had significantly higher levels of VO(2max) (P<0.05). Being persistently active was also independently associated with a high level of VO(2max) (OR: 4.4, 95%CI: 1.0-19.2). However, the rate of decline in VO(2max) with age was apparently greater in persistently active subjects compared with their persistently inactive peers, but the differences were not statistically significant.Our findings suggest that maintaining a high level of physical activity may lead to higher levels of VO(2max).
Cycle ergometer
Metabolic equivalent
Physical activity level
Physical exercise
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Introduction: VO2 max is the maximum oxygen amount of that can be consumed during intense physical activity until eventually fatigue occurs. A person with a good level of VO2 max means having good physical fitness as well. Physical fitness gives the ability to a person to do daily productive work in the absence of excessive fatigue. The low one cardiorespiratory fitness may incrase the risk of death from heart disease and hypertension. Giving freeletic exercise is one of the techniques used to improve cardiorespiratory fitness or VO2 max. Methods: This research is Pre-experimental research with one group pre-post test design. The sample of the study amounted to 20 people and freeletic exercise was given 12 times. The measuring tool used is Multistage Test of Fitness / Beep Test to know the level VO2 max of sample before and after freeletic sporting practice. Results: The results of this study indicate that 17 respondents experienced a significant increase in VO2 max and 3 other respondents did not experience improvement by giving 12 times freeletic sports exercise. Conclusion: Based on Paired T test to know whether or not there is influence, it can be concluded that there is influence of giving freeletic sport to max VO2 level on freeletic community member after given 12 times (p< 0,001, p<0,05) freeletic sport practice.
Fitness test
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Multi-stage fitness test
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Cardiorespiratory fitness is inversely associated with a high risk of cardiovascular disease, all-cause mortality, and mortality attributable to various cancers. It is often estimated indirectly using mathematical formulas for estimating oxygen uptake. Cardiopulmonary exercise testing, especially oxygen uptake, represents the "gold standard" for assessing exercise capacity. The purpose of this report was to develop reference standards for exercise capacity by establishing cardiorespiratory fitness values derived from cardiopulmonary exercise testing in a Brazilian population. We focused on oxygen uptake standards and compared the maximal oxygen uptake [mLO2·kg-1·min-1] values with those in the existing literature.A database was constructed using reports from cardiopulmonary exercise testing performed at Fleury laboratory. The final cohort included 18,189 individuals considered to be free of structural heart disease. Percentiles of maximal oxygen uptake for men and women were determined for six age groups between 7 and 84 years. We compared the values with existing reference data from patients from Norway and the United States.There were significant differences in maximal oxygen uptake between sexes and across the age groups. In our cohort, the 50th percentile maximal oxygen uptake values for men and women decreased from 44.7 and 36.3 mLO2·kg-1·min-1 to 28.4 and 22.3 mLO2·kg-1·min-1 for patients aged 20-29 years to patients aged 60-69 years, respectively. For each age group, both Norwegian men and women had greater cardiorespiratory fitness than cohorts in the United States and Brazil.To our knowledge, our analysis represents the largest reference data for cardiorespiratory fitness based on treadmill cardiopulmonary exercise testing. Our findings provide reference values of maximal oxygen uptake measurements from treadmill tests in Brazilian populations that are more accurate than previous standard values based on workload-derived estimations. This data may also add information to the global data used for the interpretation of cardiorespiratory fitness.
Treadmill
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This study tries to discuss maximum oxygen consumption (V̇O2max) strategy and its importance to build up a healthy society worldwide. V̇O2max is an important predictive factor of cardiovascular health, morbidity, and all-cause mortality; and consider it as the gold standard measure of cardiorespiratory fitness. Regular and long-time physical exercise, and exercise training are effective means of increasing V̇O2max. This research aims to increase V̇O2max and endurance capacity through the prolonged strenuous exercise, hardworking, and exercise training.
Aerobic Exercise
Cardiovascular fitness
Endurance Training
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Cardiorespiratory fitness is indicated by the body's ability to transport oxygen from the surrounding air to the contracting muscle, and the muscle's capacity to use oxygen. Cardiorespiratory fitness relies on the effective integration of the cardiovascular pulmonary, hematologic, and skeletal muscle systems. Maximal oxygen uptake is considered the best measure of cardiorespiratory fitness. A low level of maximal oxygen uptake is associated with a markedly increased cardiovascular and all-cause mortality both in healthy subjects and cardiac patients. Randomized, controlled trials are still needed, however, to further clarify the value of the assessment of cardiorespiratory fitness in clinical decision-making.
Oxygen transport
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Cardiorespiratory fitness programs are increasingly used in stroke rehabilitation. Maximal oxygen uptake is the gold standard measurement of cardiorespiratory fitness; however, no recent publications have collated evidence about maximal oxygen uptake levels following stroke. We therefore performed a systematic review of maximal oxygen uptake in stroke survivors, aiming to observe changes in levels over time, and associations with severity of stroke. We searched Medline and Embase until April 2011, and included cross-sectional studies, longitudinal studies, and baseline data from intervention trials. Studies had to recruit at least 10 stroke survivors, and report direct measurement of maximal/peak oxygen uptake. We then compared maximal oxygen uptake with published data from age and gender-matched controls. The search identified 3357 articles. Seventy-two full texts were retrieved, of which 41 met the inclusion criteria. Time since stroke ranged from 10 days to over seven-years. Peak oxygen uptake ranged from 8 to 22 ml/kg/min, which was 26–87% of that of healthy age- and gender-matched individuals. Stroke severity was mild in most studies. Three studies reported longitudinal changes; there was no clear evidence of change in peak oxygen uptake over time. Most studies recruited participants with mild stroke, and it is possible that cardiorespiratory fitness is even more impaired after severe stroke. Maximal oxygen uptake might have been overestimated, as less healthy and older stroke survivors may not tolerate maximal exercise testing. More studies are needed describing mechanisms of impaired cardiorespiratory fitness and longitudinal changes over time to inform the optimal ‘prescription’ of cardiorespiratory fitness programs for stroke survivors.
Stroke
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Physical activity level and cardiorespiratory fitness are both inversely associated with the risk of cardiovascular diseases and with all-cause mortality. Physical activity questionnaires are often validated against objectively measured maximal oxygen uptake (VO2max).To validate a self-report physical activity questionnaire against VO2max and furthermore to establish whether a simple question on self-rated physical fitness could predict objectively measured VO2max.A total of 102 men and women aged between 35 and 65 years were recruited from an ongoing population-based intervention study, the Inter99 Study. Participants reported their self-rated fitness and daily physical activity using a new questionnaire based on metabolic equivalents (MET). VO2max (ml/kg per min) was determined using a graded bicycle test with increasing workload until exhaustion and with simultaneous measurement of breath-to-breath oxygen uptake in 15-s periods. Statistical analyses were performed by linear regression analyses using the self-reported physical activity level as an independent variable and VO2max (l/min) as an dependent variable, and with covariates sex, age and bodyweight.Data from 53 men and 47 women were analysed. The amount of daily vigorous activity (>6 MET) was significantly positively associated with VO2max (P=0.0001, R=0.76), whereas the total amount of physical activity was not significantly associated with VO2max (P=0.098, R=0.69). A significant trend across three groups of self-rated fitness in relation to VO2max (ml/kg per min) was found (P for trend <0.0001).The physical activity questionnaire has acceptable validity when compared with VO2max in adult men and women. Furthermore, a simple question on self-rated fitness seems to reflect measured VO2max objectively.
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