Increase In VO2max Research Articles

Positive impact of prescribed physical activity on symptoms of schizophrenia: randomized clinical trial.

The purpose of this study was to examine functional capacity of cardio-respiratory system in patients with schizophrenia, and to evaluate the effects of 12 weeks prescribed physical activity on aerobic capacity and symptoms of schizophrenia. Study involved 80 hospitalized patients with any of the subtypes of schizophrenia (42 men, 38 women). They were divided into two groups: exercise and control group, both with 40 patients. Maximal aerobic capacity (VO2 max) as an indicator of cardiovascular fitness has been obtained by cardiopulmonary stress test on a treadmill. Twelve weeks program of prescribed physical activity (45 minutes, four times per week) was made for every patient individually. Patients in exercise group practiced in training zone between 65 and 75% of their maximum heart rate (HR). Target HR was controlled by Polar F4 monitors. Symptoms of schizophrenia were measured by using Positive and Negative Symptoms Scale (PANSS). Before the exercise program was introduced, measured VO2 max was significantly lower in patients with schizophrenia, than the expected average value in matched healthy subjects (p<0.001). After twelve weeks, patients in exercise group showed a significant increase of VO2max (p=0.002), and significantly higher level of VO2max compared to the control group (p=0.000). Significant differences were also observed on PANSS general psychopathology subscale (p=0.007) and on PANSS total score (p=0.001). The pharmacotherapy and exercise had influence on PANSS general psychopathology (p=0.002) and PANSS total score (p=0.001). Individuals with schizophrenia have lower levels of aerobic capacity compared to general population. Prescribed physical activity significantly improves aerobic capacity in people with schizophrenia and it is effective in amelioration of some psychiatric symptoms. Prescribed physical activity could be an effective adjunctive treatment for patients with schizophrenia, not only for prevention and treatment of comorbidities, but also having an impact on symptoms of schizophrenia.

Exercise more or sit less? A randomized trial assessing the feasibility of two advice-based interventions in obese inactive adults

ObjectivesThe risk of metabolic and cardiovascular disease may be reduced by a healthy pattern of daily physical activity. We investigated the feasibility and preliminary effectiveness of advice-based interventions aiming at either increasing moderate-to-vigorous intensity physical activity (MVPA) or reducing sedentary time (ST) in obese volunteers. DesignRandomized non-blinded two-armed trial. MethodInactive, obese adults were randomly assigned to reduce sedentary behavior (SitLess) (n=30) or increase MVPA (ExMore) (n=29) for 4 weeks. Participants wore ActivPAL (AP) and ActiGraph (AG) devices for 7 consecutive days at baseline and during the final week of the intervention period. Cardiometabolic risk factors (waist circumference, BMI, percent body fat, blood pressure, VO2max and blood markers) were measured at baseline and at follow-up. Trial was set in Midtjylland Denmark from 2012 to 2014. ResultsThe interventions were completed by 77% (SitLess) and 69% (ExMore) of the participants. The SitLess group reduced sedentary time by 53min/day (95% CI 10; 96; P<0.05) while ExMore increased MVPA by 16min/day (95% CI 5; 27; P<0.05). SitLess and ExMore both improved VO2max by 8% and 11%, respectively (P<0.05). None of the other measured cardiometabolic risk factors changed over the 4 weeks of intervention. ConclusionsThis trial showed that completion of 4-week, advice-based interventions led to reduced ST or increased MVPA in obese adults. Furthermore, both interventions led to small significant increases in VO2max. Studies of longer duration are needed to determine if these behavioral changes can be maintained, and to quantify possible longterm effects of reduced ST or increased MVPA on cardiometabolic risk factors.

Analýza efektu vysoce intenzivního intervalového tréninku (HIIT)

The HIIT – High Intensity Interval Training has become an increasingly used term in foreign publications and this method is frequently implemented in training processes of many athletes. However not every athlete or trainer is aware of the physiological changes which are caused by this form of training. In order to improve the training process it is important to compare the effectiveness of HIIT with the continual training method or other forms of the interval training. The aim of this publication is to analyze and describe the effect of various forms of HIIT according to the set markers: primarily VO2 max (maximal oxygen uptake) – interval training effectiveness marker, secondarily lipid utilization, and last but not least hormonal and enzymatic level changes. Another objective of this publication is the clarification and explanation of energy coverage, metabolism and cardio-respiratory function during the application of HIIT method. Within the research plan we focused exclusively on the foreign studies (n = 150) conducted in years 1978–2015 from which we chose 70 studies from databases such as SportDiscus, Web of Science, ACSM Journal, PubMed. The selection was based on the preselected criteria – length of the research, nature of the research group and intervention frequency etc. For the purpose to extend the theoretical bases of the problematics of energy coverage, metabolism and cardio-respiratory function were analyzed several chosen studies from last 10–15 years. The analysis of the individual markers was conducted based on the publications from the last decade. The research has shown that the HIIT has a significant effect on the increase of VO2 max. Further findings also showed that the subject is able to adapt to this type of training in just two weeks which enables the duration of training process to shorten. This type of training also leads simultaneously with EPOC effect (post-exercise oxygen consumption) to higher energy consumption in tens of hours. The presented results can be used in Sports practice to overcome the performance stagnation and lead to performance improvement as a result of the HIIT method implementation. Certain studies show that the HIIT method is also successfully applicable to the overweight individuals, patients with Diabetes mellitus and people with sedentary lifestyle. However, it is always necessary to ensure the individual approach and to avoid the risk of overtraining.

Pengaruh pemberian sari umbi bit (beta vulgaris) terhadap kadar hemoglobin dan performa atlet sepak bola

Background: Nutritional factors in athletes were very influential to lead achievement. Giving special food or drink is also important to improve VO2max. One of the substances that can optimized the levels of VO2max is the content of nitrates in foodstuffs. The beetroot is one source of food with high nitrate content.Objective: This study aimed to analyze the effect of bit extract (beta vulgaris) on Hb Levels and performance among football athleteMethods: Design of quasi experimental research with pretest-post test control group approach, conducted on 18 athletes of UNNES Football Club aged 18-22 years. The treatment of beetroot juice was given for 7 days, consist of P200 treatment group consumed 200 ml, P300 was given 300 ml, while control consumed 300 ml of syrup with the same color with beet extract. Athlete’s performance was obtained with VO2max levels. VO2max measurements were taken twice using MFT (multistage fitness test) on day 1 before intervention and day 7 after intervention. Confounding variables were energy intake, macronutrient intake, iron intake, vitamin C intake, and smoking habits. The analysis using by paired-t-test, kruskal wallis, and one way anova.Result: Most subjects had intake (energy, carbohydrate, fat, protein, iron and vitamin C) less categories. Most of the subjects had a good category VO2 Max and were excellent, as well as not anemic. There was no significant effect of treatment on VO2 Max and Hb level (p &lt;0.05), but the increase in VO2 Max was greater in group P 300 than in group P 200 and control. Hb levels of subjects after intervention decreased, but still relatively normal levels. Conclusions: There was no significant effect of giving beetroot juice on VO2 Max and Hb levels, but the increase in VO2 Max in group P 300 was higher than in P group of 200 and control group.

Short Communication: HIV Patient Systemic Mitochondrial Respiration Improves with Exercise.

In HIV-infected individuals, impaired mitochondrial function may contribute to cardiometabolic disease as well as to fatigue and frailty. Aerobic exercise improves total body energy reserves; however, its impact at the cellular level is unknown. We assessed alterations in cellular bioenergetics in peripheral blood mononuclear cells (PBMC) before and after a 12-week aerobic exercise study in sedentary HIV-infected subjects on stable antiretroviral therapy who successfully completed a 12-week aerobic exercise program. In this prospective study, participants underwent supervised 20-40 min of light aerobic exercise (walking or jogging) performed three times per week for 12 weeks, gradually increasing to maintain an intensity of 50%-80% of heart rate reserve. Maximal aerobic capacity (VO2MAX) was assessed by a graded exercise test on a cycle ergometer before and after completion of the study. PBMC from compliant subjects (attended at least 70% of exercise sessions) were assessed for mitochondrial respiration using the Seahorse XF24 Bio-Analyzer. Seven of 24 enrolled subjects were compliant with the exercise regimen. In these individuals, a significant increase (p = .04) in VO2MAX over 12 weeks was found with a median increase of 14%. During the same interval, a 2.45-fold increase in PBMC mitochondrial respiratory capacity (p = .04), a 5.65-fold increase in spare respiratory capacity (p = .01), and a 3.15-fold (p = .04) increase in nonmitochondrial respiration was observed. Aerobic exercise improves respiration at the cellular level. The diagnostic and prognostic value of such improved cellular respiration in the setting of chronic HIV warrants further investigation.

Heart rate reduction and exercise performance in recent onset heart failure with reduced ejection fraction: arguments for beta-blocker hypo-response.

Beta blockers reduce all-cause mortality and readmissions in heart failure with reduced ejection fraction (HFrEF), which may be explained by their effect on heart rate (HR). This study assessed the impact of HR reduction with beta blockers on exercise capacity in recent onset HFrEF. Fifty consecutive patients with recent onset HFrEF (<30 days) performed a standardized exercise protocol with respiratory gas analysis at baseline as well as after 6 and 12 months. Patients participated in a quality of care programme aiming to achieve guideline-recommended target doses for beta-blocker therapy. At baseline, 6 and 12 months, 36%, 70% and 62% of patients, respectively, had a resting HR<70 bpm. Beta-blocker dose after 12 months was comparable in patients with resting HR<70 versus ≥70 bpm (P value=0.631). However, with similar dose uptitration, the former versus the latter had a significantly larger HR reduction (17±22 versus 4±15 bpm; P value=0.027). Peak oxygen consumption (VO2max) was significantly higher when resting HR was <70 versus ≥70 bpm (17.5±5.5 versus 14.4±3.3 mL/min/kg, respectively; P value=0.038). Similar results were observed after 6 months. Patients in whom resting HR decreased at follow-up compared to baseline had a 2.0±3.2 mL/min/kg increase in VO2max compared to a 1.2±7.7 mL/min/kg increase in patients who did not demonstrate a lower resting HR (P value=0.033). In recent onset HFrEF, exercise performance was better when resting HR was controlled <70 bpm with beta-blocker therapy. However, despite aggressive dose uptitration, many patients did not achieve this target as they had little HR reduction with beta-blocker therapy.

Effect of Prolonged Endurance Training on Ambulatory Systolic Blood Pressure and Arterial Function

Healthy, sedentary aging is associated with marked increased risk for developing (systolic) hypertension, which is partially driven by changes in arterial stiffness. In contrast, lifelong exercise training mitigates the effects of aging on arterial stiffness. PURPOSE: We compared the effects a prolonged, intensive supervised exercise training intervention to two-years of sedentary aging on arterial function and ambulatory BP. METHODS: Sixty one healthy subjects (52.4±5.1 years, 46% male) were randomized to either non-exercise control (Con; n=27) or aerobic exercise training (ExT; n=34). A comprehensive assessment of arterial function including aortic PWV and indices derived from the central BP waveform, plus resting hemodynamics were performed at baseline (Pre), 10 months (Mid) and two-years (Post). Ambulatory blood pressure was measured at Pre and Post. RESULTS: There was excellent adherence to the training intervention (89±9%) resulting in a 21% increase in VO2 max, with no change in Con. Ambulatory systolic BP was significantly increased, while ambulatory and resting HR were significantly reduced in the ExT group (Table 1). In contrast to our hypothesis, large artery function (AIx75, time to reflected wave, aortic PWV) was not improved following exercise training. CONCLUSION: Despite improved exercise capacity and excellent training adherence, large artery function was not improved in the ExT group. Consequently, ambulatory systolic BP was significantly increased, partially due to the lack of change in stiffness and the increased stroke volume associated with training. Supported by NIH Grant RO1 AG017479Table 1: Effect of two-years of supervised endurance training on hemodynamics and arterial functionValues are mean ± SEM, * P< 0.05 compared to Pre. SBP, systolic blood pressure; DBP diastolic blood pressure; HR, heart rate; bpm, beats per minutes; PWV, pulse wave velocity; AIxHR75, augmentation index heart rate corrected; T1R, time to reflected wave

Comparison of the Talk Test and Percent Heart Rate Reserve for Exercise Prescription

Exercise intensity is traditionally prescribed using %HRmax, %HRR, %VO2max or %VO2R. Recently, the Talk Test (TT) has been proposed as an alternative method to guide exercise intensity. However, it is unknown if prescribing exercise intensity solely using the TT can provoke training responses that are comparable to traditional guidelines. PURPOSE: To compare the training responses consequent to training using either the TT or %HRR. METHODS: Forty-four subjects (17 males and 27 females: age=20.4+3.02 yrs; ht=170.5+9.79 cm; wt=71.9+13.63 kg) completed an incremental maximal cycle ergometer test, were stratified by VO2max and gender, and randomly assigned to training groups guided by either %HRR (n=20) or the TT (n=24). Both groups completed 40-minute training sessions 3 days per week for 10 weeks. In the HRR group, exercise intensity was targeted at 40-59 %HRR for weeks 1-4, 50-59 %HRR for weeks 5-8, and 60-79 %HRR for weeks 9-10. In the TT group, exercise intensity was targeted at the highest power output that still allowed for comfortable speech. Changes in VO2max, peak power output (PPO – watts and watts/kg), ventilatory threshold (VT); and PO at VT, were compared between groups using two-way ANOVA with repeated measures. RESULTS: There were significant (p<.05) pre vs. post increases in VO2max (TT=+10.6%; HRR=+11.5%), PPO - watts (TT=+18.5%; HRR=+14.1%), PPO - watts/kg (TT=+19%; HRR=+14%), VT (TT=+56.9%; HRR=+32.7%), and PO at VT (TT=+39%; HRR=+43%) in both groups as a result of training, with no significant differences (p>.05) in the magnitude of improvement between groups. CONCLUSION: Guiding exercise prescription using the TT is a simple and effective method for prescribing exercise intensity and elicits improvements in exercise performance that are comparable to traditional %HRR guidelines.

Effect of high-dose ginsenoside complex (UG0712) supplementation on physical performance of healthy adults during a 12-week supervised exercise program: A randomized placebo-controlled clinical trial

BackgroundGinseng has been used as an ergogenic agent, although evidence for its effectiveness is weak. A randomized, double-blind, placebo-controlled clinical trial was conducted to evaluate the effect of a ginsenoside complex (UG0712) on changes in exercise performance. MethodsSedentary individuals (n=117) were randomly assigned into one of three groups: low-dose ginsenoside supplementation (100 mg/d, n=39), high-dose ginsenoside supplementation (500 mg/d, n=39), or a placebo group (500 mg/d, n=39). All participants underwent a supervised 12-wk aerobic and resistance exercise training course. To assess the effects of supplementation on physical performance, maximal oxygen consumption (VO2max), anaerobic threshold (AT), lactic acid, and muscle strength of the dominant knee were measured at baseline, every visit, and after the training program. ResultsBoth ginsenoside groups showed significant increases in VO2max and muscular strength during exercise training. There were no definite changes in AT and lactic acid levels over time. After exercise training, there were definite differences in the VO2max (28.64.9 to 33.7±4.9 ml/kg/min in high-dose group vs. 30.4±6.7 to 32.8±6.6 ml/kg/min in placebo, p=0.029) and AT (19.3±4.2 to 20.9±3.5 ml/kg/min in high-dose group vs. 20.0±5.1 to 20.0±4.9 ml/kg/min in placebo, p=0.038) between the high-dose ginsenoside and placebo groups. However, there was no difference in VO2max between the low-dose ginsenoside and placebo groups (p=0.254). There were no differences in muscular strength during exercise training among the three groups. ConclusionHigh-dose ginsenoside supplementation (UG0712) augmented the improvement of aerobic capacity by exercise training.

Exercise intolerance in heart failure with preserved ejection fraction: time to scrutinize diuretic therapy?

Exercise intolerance in heart failure with preserved ejection fraction: time to scrutinize diuretic therapy?

Abstract MP030: The Association Between Objectively Measured Sleep, Physical Activity and Sedentary Behaviour on Cardiorespiratory Fitness and Health in 9 - 11 Year Old New Zealand Children

Background: The role of activity, sedentary behaviour and sleep in cardiorespiratory fitness (CRF) or cardiovascular health, has been primarily studied in adults. Therefore we assessed the hypothesis that longer sleep duration, more time spent in moderate to vigorous activity (MVPA), less sedentary time and a lower ratio of sedentary time to MVPA (Sedentary: MVPA) would be associated with higher CRF and lower pulse wave velocity (PWV) in children aged nine to 11 years from Dunedin, New Zealand. Methods: A cross-sectional study. Information on demographics and lifestyle was collected by questionnaire. Data on sleep, sedentary and MVPA time were collected using Actigraph wGT3X-BT accelerometers, worn over eight days. PWV was obtained using the SphygmoCor Xcel. VO 2 max values, from a multi-stage 20-metre shuttle run test, were used as the measure of CRF. Generalised estimating equations were undertaken to investigate relationships between accelerometer derived variables and CRF and PWV separately in 404 participants. Analyses were adjusted for age, socioeconomic status, ethnicity and age and sex specific BMI Z scores. Results: Mean (SD) VO 2 max was 47.5 (4.1) Ml/Kg/min for girls and 49.9 (5.20) for boys and mean (SD) PWV was 5.72 (0.79) for girls and 5.85 (0.79) for boys. In multivariate models, a one hour increase in sedentary time was associated with a 0.81 (CI: -1.19, -0.42) Ml/Kg/min increase in VO 2 max in all participants. In boys only, a one hour increase in MVPA associated with a 3.50 (CI: 2.76, 4.20) Ml/Kg/min increase in VO 2 max. Sedentary: MVPA was associated with lower VO 2 max in boys and girls. Sedentary time (β 0.15 m/s per hour increase, CI: 0.02, 0.27) and MVPA (β 0.25 m/s per hour decrease, CI: 0.04, 0.46) were only significantly associated with PWV in boys. No significant assocaitions were seen between sleep and CRF or PWV. Conclusions: In conclusion, sedentary behavior, MVPA and Sedentary: MVPA were both associated with CRF and PWV. Our results suggest that future interventions aimed at improving heart health in this age group need to target both increasing physical activity and reducing sedentary time. Funding sources: The National Heart Foundation of New Zealand and The University of Otago.

Maximal aerobic capacity can be increased by enhancing performers' expectancies.

Maximum aerobic capacity (VO2max) is widely accepted as the best measure of cardiovascular fitness and aerobic power. The present study investigated whether enhancing participants' performance expectancies through positive social-comparative feedback would increase VO2max. Participants were experienced runners who regularly ran for exercise or competitively. All participants completed two VO2max tests within a 2-week period at similar times of the day. Before the second test, enhanced expectancy group participants were informed that their aerobic capacity on the first test was above the group average, whereas control group participants were told the second test was for validation purposes. Measurements taken were relative to VO2max, as well as pulmonary ventilation, respiratory exchange ratio, heart rate, and ratings of perceived exertion. The enhanced expectancy group demonstrated a significant increase (+3.28%) in VO2max from test 1 (61.1±2.8 mL·kg-1·min-1) to test 2 (63.7±2.9 mL·kg-1·min-1, P=0.007), whereas the control group's VO2max decreased significantly (-4.11%, test 1 =59.4±2.9 mL·kg-1·min-1, test 2 =57.8±2.3 mL·kg-1·min-1, P=0.027). No group differences were found with respect to other performance measures (pulmonary ventilation P=0.22, heart rate P=0.97, respiratory exchange ratio P=0.11, rate of perceived exertion P=0.13). The results show that maximum aerobic capacity is, in part, a function of the performer's self-efficacy expectations. These findings add to the increasing evidence demonstrating social-cognitive-affective influences on (maximum) motor performance.

Does High Intensity Interval Training Improve Aerobic Power Development More Than Endurance Training?

The purpose of this study was to determine whether high intensity interval training (HIIT) increases VO2 max more so than to endurance training (ET). It is hypothesized that at the end of a 4-week training program, the HIIT group will have a higher average improved VO2 max percentage than the ET group. Recruited participants, 12 males, aged 18-35 completed a baseline VO2 max test followed by an intervention and then a post VO2 max test. Participants were randomly assigned to either HIIT or ET, 20 minutes a day, 3 times a week for 4 weeks. At baseline mean VO2 max for ET (n=6) was 48.2 ml/min/kg compared to a mean VO2 max of 51.7ml/min/kg in the HIIT (n=6) group. Post training test VO2 max for ET (n=6) was 48.9ml/min/kg compared to a mean VO2 max of 52.4ml/min/kg in the HIIT group (n=4). There was a 3.4% improvement in VO2 max in the HIIT group (n=4), while the ET group (n=6) had a 1.7% improvement in VO2 max. There were no significant differences (p&gt;0.05) in height, weight, age, and VO2 max between the two groups in the baseline or post test. There were no significant differences in height, age, and VO2 max for either of the groups from the post test compared to the baseline test. Moreover, there were no significant differences in height, age, and VO2 max for either of the groups from the post-test compared to the baseline test. The data suggests a promising trend that HIIT training may be better for improving aerobic power than ET.

Association of Occupational and Leisure-Time Physical Activity with Aerobic Capacity in a Working Population

IntroductionObjective data on the association of maximal aerobic capacity (VO2max) with work related physical activity are sparse. Thus, it is not clear whether occupational physical activity (OPA) contributes to an increase of VO2max. This study examined the association of VO2max with work and non-work related physical activity in a Swiss working population.MethodsIn this cross-sectional study, a total of 337 healthy and full-time employed adults were recruited. Demographic data, height, weight and BMI were recorded in all subjects. Participants were classified into nine occupational categories (ISCO-88) and merged into three groups with low, moderate, and high OPA. Physical activity was objectively measured by the SenseWear Mini Armband on seven consecutive days (23 hours per day). Participants were regarded as sufficiently active when accumulating ≥30 min of moderate-to-vigorous physical activity per day. VO2max was evaluated using the multistage 20-meter shuttle run test.ResultsData of 303 participants were considered for analysis (63% male, age 33 yrs, SD 12). Multiple linear regression analysis (adjusted R2 = 0.69) revealed significant positive associations of VO2max with leisure-time physical activity (LTPA) at vigorous intensity (β = 0.212) and sufficient moderate-to-vigorous physical activity (β = 0.100) on workdays. Female gender (β = -0.622), age (β = -0.264), BMI (β = -0.220), the ratio of maximum to resting heart rate (β = 0.192), occupational group (low vs. high OPA, β = -0.141), and smoking (β = -0.133) were also identified as independent predictors of VO2max.ConclusionsThe present results suggest that VO2max is positively associated with LTPA, but not with OPA on workdays. This finding emphasizes the need for employees to engage in sufficient high-intensity physical activity in recreation for maintaining or improving VO2max with regard to health benefits.

Modulation of VO2 max by Rajyoga meditation in young adult males

Background: Relaxation of body mind with positive approach has been successfully achieved by Rajyoga meditation. It is the science and art of harmonizing spiritual mental and physical energy. Meditation has a number of positive effects on the physiology of human body. Physical fitness depends mainly on cardiorespiratory endurance of an individual. VO2 max (maximal oxygen uptake/maximal aerobic power/aerobic capacity) is widely accepted as the best measure of cardiorespiratory endurance. Aims and Objectives: To find out the effect of Rajyoga meditation on VO2 max. Materials and Methods: 40 healthy male volunteers in the age group of 18-20 years were included in the study. They were randomly allocated into control and intervention groups by blind-cheat technique with 20 participants in each group. Group-A participants were control while Group-B participants were given intervention in the form of Rajyoga meditation under the guidance of Rajyoga trainer for duration of 4 months. VO2 max was assessed in both groups using AD-instrument before and after 4 months study. Results: Student’s paired t-test was used to compare pre- and post-interventional results. Increased VO2 max was seen in intervention group as compared to control group. P < 0.05 was considered statistically significant. Conclusion: VO2 max indicates aerobic capacity and physical fitness of an individual. Increased VO2 max after Rajyoga meditation ensures good cardiorespiratory endurance.

Chronotype and response to training during the polar night: a pilot study

ABSTRACTBackground: An individual’s chronotype influences his or her physiological rhythms. Some studies have looked at the effect of time of day on the responses to exercise, but studies on the effect of long-term training are lacking.Objective: To report the effects of an 8-week training period during the polar night in non-athletes of different chronotypes living at 70°N.Design: In all, 10 morning (M), 10 neither (N) and 10 evening (E) types were recruited, and their aerobic capacity (VO2max), strength, flexibility and balance before and after the training period were tested.Results: 3 E-types, 5 N-types and 6 M-types completed the protocol. An increase in VO2max and strength was observed for the whole group. The best negative correlation (r=–0.5287) was found between the Morningness–Eveningness Questionnaire (MEQ) score and the increase in VO2max, and the best positive correlation (r=0.4395) was found between MEQ and the increase in strength. Changes in balance and flexibility did not show any clear trends.Conclusion: In an environment with no outdoor daylight, it seems that the response to 8 weeks of aerobic training is larger in the E- than in the M-types, although the M-types showed a larger improvement in strength.

Cardiovagal Tone: A Predictor of Heart Rate Adjusted Augmentation Index in Men but Not in Women

Purpose: Aortic augmentation index (AIx) and cardiovagal tone (CVT) are indicators of cardiovascular health. Associations between these variables provide information about their roles in cardiovascular disease. However, evaluating these associations from a gender perspective and gaining an understanding of the relationship between cardiorespiratory fitness and AIx based on gender can provide additional information. Therefore, we examined the relationships between CVT, measured as the log transformed high-frequency power of R-R intervals from electrocardiogram measurements (lnHFR-R); cardiorespiratory fitness, measured as maximum oxygen consumption (VO2max); and AIx at a heart rate of 75 beats·min-1(AIx@75). We hypothesized that the relationships between CVT, cardiorespiratory fitness, and AIx@75 would differ based on gender. Methods: We examined the associations between lnHFR-R, VO2max, and AIx@75 in 41 women and 39 men. Power spectral density analysis of heart rate variability determined lnHFR-R, radial tonometry determined AIx@75 and the Bruce Treadmill Protocol determined VO2max. Results: In men, lnHFR-R positively correlated with and significantly predicted AIx@75 (P = 0.005) but not in women (P = 0.49). For every unit increase in lnHFR-R, there was a 4.6 unit increase in AIx@75 in men versus a 1.0 unit increase in women. There was a significant inverse relationship between VO2max and AIx@75, with VO2max being a significant predictor of AIx@75 in men (P = 0.01). For every unit increase in VO2max, there was a 0.60 unit decrease in AIx@75 in men versus a 0.2 unit decrease in women. Conclusions: The associations between CVT and AIx@75 and between cardiorespiratory fitness and AIx@75 differ by gender. CVT and cardiorespiratory fitness are significant predictors of AIx@75 in men but not in women.

Biology of VO2 max: looking under the physiology lamp.

In this review, we argue that several key features of maximal oxygen uptake (VO2 max) should underpin discussions about the biological and reductionist determinants of its interindividual variability: (i) training-induced increases in VO2 max are largely facilitated by expansion of red blood cell volume and an associated improvement in stroke volume, which also adapts independent of changes in red blood cell volume. These general concepts are also informed by cross-sectional studies in athletes that have very high values for VO2 max. Therefore, (ii) variations in VO2 max improvements with exercise training are also likely related to variations in these physiological determinants. (iii) All previously untrained individuals will respond to endurance exercise training in terms of improvements in VO2 max provided the stimulus exceeds a certain volume and/or intensity. Thus, genetic analysis and/or reductionist studies performed to understand or predict such variations might focus specifically on DNA variants or other molecular phenomena of relevance to these physiological pathways.

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.

INTER-INDIVIDUAL DIFFERENCES IN THE RESPONSES OF VO2MAX TO PHYSICAL ACTIVITY COUNSELLING

Low cardiorespiratory fitness (VO2max) is an important risk factor for diabetes, cardiovascular disease and some cancers, making lifestyle interventions especially relevant. There is purported to be substantial inter-individual differences in...