Effects of chronic metformin treatment on training adaptations in men and women with hyperglycemia: A prospective study
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Abstract Objective This study aimed to determine whether chronic metformin use interferes with the improvements in insulin resistance (IR) and cardiorespiratory fitness with aerobic training in people with hyperglycemia and metabolic syndrome (MetS). Methods A total of 63 middle‐aged (53 [7] years) individuals with MetS and obesity (BMI = 32.8 [4.5] kg/m 2 ) completed 16 weeks of supervised high‐intensity interval training (3 d/wk, 43 min/session). Participants were either taking metformin (EXER+MET; n = 29) or were free of any pharmacological treatment for their MetS factors (EXER; n = 34). Groups were similar in their initial cardiorespiratory fitness (maximal oxygen uptake [VO 2MAX ]), age, percentage of women, BMI, and MetS factors ( z score). The effects of exercise training on IR (homeostatic model assessment of insulin resistance [HOMA‐IR]), MetS z score, VO 2MAX , maximal fat oxidation during exercise, and maximal aerobic power output were measured. Results Fasting insulin and HOMA‐IR decreased similarly in both groups with training (EXER+MET: −4.3% and −10.6%; EXER: −5.3% and −14.5%; p value for time = 0.005). However, metformin use reduced VO 2MAX improvements by half (i.e., EXER+MET: 12.7%; EXER: 25.3%; p value for time × group = 0.012). Maximal fat oxidation during exercise increased similarly in both groups (EXER+MET: 20.7%; EXER: 25.3%; p value for time = 0.040). VO 2MAX gains were not associated with HOMA‐IR reductions (EXER+MET: r = −0.098; p = 0.580; EXER: r = −0.255; p = 0.182). Conclusions Metformin use was associated with attenuated VO 2MAX improvements but did not affect fasting IR reductions with aerobic training in individuals with hyperglycemia and high cardiovascular risk (i.e., MetS).Keywords:
Aerobic Exercise
Interval training
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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The purpose of this study was to analyze the effects of intermttient and continuous aerobic exercise onbody composition, cardiorespiratory fitness and immunoglobulin in the middle-aged women. The subjectswere 21 middle-aged women. They were divided into two groups: ocntinuous aerobic training group (CAT , n=11) and intermittent aerobic training group (IAT, n=10). The exercise program consists of 40-60%HRR, 60min/day, 3 days/week for 12 weeks. Body composition, cardiorespiratory fitness, immunoglobulin levels weremeasured in all subjects at week-0, week-4, week-8, and week-12. All data were analyzed by Two-wayrepeated measures ANOVA and One-way ANOVA using SPSS version 2.10. These results indicate that co-ntinuous aerobic exercise has more beneficial effect on improvements in cardiorespiratory fitness compared tointermittent aerobic exercise, while no beneficial effects on changes in body composition and immunoglobulinthan intermittent aerobic exercise. This suggests that about 4w eeks of detraining does not result in advers eeffects on metabolic and immune function in apparently healthym iddle-aged woman if about 4 weeks of r-etraining follows.
Aerobic Exercise
Aerobic capacity
Repeated measures design
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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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Cardiovascular disease (CVD) is the main cause of death for adults in the world. CVD in the future will be one of the problems that will persist in long term. Someone who has high cardiorespiratory fitness (CRF) and VO2 max has a low risk of developing CVD. One aspect of CVD prevention is exercise to improve cardiorespiratory fitness. High intensity interval training (HIIT) is an exercise that has many benefits, one of which is increasing cardiovascular fitness by increasing VO2 max. With an increase in VO2 max, the risk for CVD will decrease and better prevention is begin at a young age. The purpose of this study is to analyze the effect of High Intensity Interval Training (HIIT) on VO2 max levels in young adult. The research method uses a Literature Review study. Data collection through Pubmed, Science direct, and Google Scholar within the last 10 years. There were 668 articles were obtained which were then screened so that 7 articles with various types of research such as comparative studies, randomized control trials and clinical trials, were suitable to be reviewed. The results showed that High Intensity Interval Training (HIIT) affected in increasing VO2 max. This is related to Reactive oxygen species (ROS) which will later affect the body's adaptive response. High Intensity Interval Training (HIIT) is better in increasing VO2 max compared to other exercise.
High-Intensity Interval Training
Interval training
Intensity
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Little is known about cardiorespiratory fitness and aerobic exercise training in older adults with Alzheimer’s disease (AD). The purposes of this article are to describe the change in cardiorespiratory fitness after 2 months of aerobic training and the feasibility of aerobic training in 4 men with moderate-to-severe AD. A one-group, pretest-posttest test design was used to measure cardiorespiratory fitness using symptom limited, graded cycle ergometer testing. In exit interviews, participants and spouses identified exercise facilitators and barriers. The results show that cardiorespiratory fitness increased in 2 participants with moderate AD but decreased in 2 with severe AD. Participants showed great variability in exercise progression and doses actually delivered. In conclusion, older men with moderate-to-severe AD can engage in aerobic training. Two months might be better used as the adaptive period for longer duration aerobic training, such as a 6-month program. Suggestions and implications for future exercise research in AD are detailed.
Aerobic Exercise
Cycle ergometer
Aerobic capacity
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This research is to propose an appropriate intensity of aerobic exercises for abdominal obese males by carrying out low intensity aerobic exercise and high intensity aerobic exercise according to their cardiorespiratory fitness level and observing variations to the TNF-α and HOMA-IR for 12 weeks. For this research, 50 abdominal obese males in their 20s were classified into five groups: a control group (CG, n=10), a low cardiorespiratory fitness level and low intensity aerobic exercise group (LCLA, n=10), a low cardiorespiratory fitness level and high intensity aerobic exercise group (LCHA, n=10), a high cardiorespiratory fitness level and low intensity aerobic exercise group (HCLA, n=10), and a high cardiorespiratory fitness level and high intensity aerobic exercise group (HCHA, n=10). Upon analysing the data, the main findings of this study are as follows. With the intensity of aerobic exercise by cardiorespiratory fitness level, TNF-α did not denote a significant difference while HOMA-IR presented a significant difference (p＜.01). During the time of erobic exercise by cardiorespiratory fitness level, TNF-αdid not denote a significant difference while HOMA-IR presented a significant difference (p＜.001). Regarding the interaction of intensity and time of aerobic exercise by cardiorespiratory fitness level, TNF-α did not denote a significant difference while HOMA-IR presented a significant difference(p＜.001). Regarding the amount of variation according to intensity of aerobic exercise by cardiorespiratory fitness level, TNF-α did not denote a significant difference while HOMA-IR presented a significant difference(p＜.001).
Aerobic Exercise
Intensity
Exercise intensity
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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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Aerobic Exercise
Center (category theory)
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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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