Effects of a Low Carbohydrate Weight Loss Diet on Exercise Capacity and Tolerance in Obese Subjects

Dietary restriction and increased physical activity are recommended for obesity treatment. Very low carbohydrate diets are used to promote weight loss, but their effects on physical function and exercise tolerance in overweight and obese individuals are largely unknown. The aim of this study was to compare the effects of a very low carbohydrate, high fat (LC) diet with a conventional high carbohydrate, low fat (HC) diet on aerobic capacity, fuel utilization during submaximal exercise, perceived exercise effort (RPE) and muscle strength. Sixty subjects (age: 49.2 ± 1.2 years; BMI: 33.6 ± 0.5 kg/m²) were randomly assigned to an energy restricted (～6–7 MJ, 30% deficit), planned isocaloric LC or HC for 8 weeks. At baseline and week 8, subjects performed incremental treadmill exercise to exhaustion and handgrip and isometric knee extensor strength were assessed. Weight loss was greater in LC compared with HC (8.4 ± 0.4% and 6.7 ± 0.5%, respectively; P = 0.01 time × diet). Peak oxygen uptake and heart rate were unchanged in both groups (P > 0.17). Fat oxidation increased during submaximal exercise in LC but not HC (P < 0.001 time × diet effect). On both diets, perception of effort during submaximal exercise and handgrip strength decreased (P ≤ 0.03 for time), but knee extensor strength remained unchanged (P > 0.25). An LC weight loss diet shifted fuel utilization toward greater fat oxidation during exercise, but had no detrimental effect on maximal or submaximal markers of aerobic exercise performance or muscle strength compared with an HC diet. Further studies are required to determine the interaction of LC diets with regular exercise training and the long‐term health effects.     

Separate and combined effects of exercise training and weight loss on exercise efficiency and substrate oxidation

Perturbations in body weight have been shown to affect energy expenditure and efficiency during physical activity. The separate effects of weight loss and exercise training on exercise efficiency or the proportion of energy derived from fat oxidation during physical activity, however, are not known. The purpose of this study was to determine the separate and combined effects of exercise training and weight loss on metabolic efficiency, economy (EC), and fat oxidation during steady-state moderate submaximal exercise. Sixty-four sedentary older (67 +/- 0.5 yr) overweight to obese (30.7 +/- 0.4 kg/m(2)) volunteers completed 4 mo of either diet-induced weight loss (WL; n = 11), exercise training (EX; n = 36), or the combination of both interventions (WLEX; n = 17). Energy expenditure, gross efficiency (GE), EC, and proportion of energy expended from fat (EF) were determined during a 1-h submaximal (50% of peak aerobic capacity) cycle ergometry exercise before the intervention and at the same absolute work rate after the intervention. We found that EX increased GE by 4.7 +/- 2.2%. EC was similarly increased by 4.2 +/- 2.1% by EX. The addition of concomitant WL to EX (WLEX) resulted in greater increases in GE (9.0 +/- 3.3%) compared with WL alone but not compared with EX alone. These effects remained after adjusting for changes in lean body mass. The proportion of energy derived from fat during the bout of moderate exercise increased with EX and WLEX but not with WL. From these findings, we conclude that exercise training, either alone or in combination with weight loss, increases both exercise efficiency and the utilization of fat during moderate physical activity in previously sedentary, obese older adults. Weight loss alone, however, significantly improves neither efficiency nor utilization of fat during exercise.     

Racial Differences in Relative Skeletal Muscle Mass Loss During Diet‐Induced Weight Loss in Women

Objective

It is unclear whether there are race‐specific differences in the maintenance of skeletal muscle during energy restriction. Changes in relative skeletal muscle index (RSMI; limb lean tissue divided by height squared) were compared following (1) diet alone, (2) diet + aerobic training, or (3) diet + resistance training.

Methods

Overweight, sedentary African American (AA; n = 72) and European American (EA; n = 68) women were provided an 800‐kcal/d diet to reduce BMI < 25 kg/m². Regional fat‐free mass was measured with dual‐energy x‐ray absorptiometry. Steady‐state VO₂ and heart rate responses during walking were measured.

Results

AA women had greater RSMI and preserved RSMI during diet alone, while RSMI was significantly reduced among EA women (EA women –3.6% vs. AA women + 1.1%; P < 0.05). Diet + resistance training subjects retained RSMI (EA women + 0.2% vs. AA women + 1.4%; P = 50.05), whereas diet + aerobic training subjects decreased RSMI (EA women –1.4% vs. AA women –1.5%; P < 0.05). Maintenance of RSMI was related to delta walking ease and economy.

Conclusions

Compared with AA women, EA women are less muscular and lose more muscle during weight loss without resistance training. During diet‐induced weight loss, resistance training preserves skeletal muscle, especially among premenopausal EA women. Maintenance of muscle during weight loss associates with better ease and economy of walking.

     

Exercise Training Prevents Regain of Visceral Fat for 1 Year Following Weight Loss

The purpose of this study was to determine what effect aerobic and resistance exercise training has on gain of visceral fat during the year following weight loss. After being randomly assigned to aerobic training, resistance training, or no exercise training, 45 European‐American (EA) and 52 African‐American (AA) women lost 12.3 ± 2.5 kg on a 800 kcal/day diet. Computed tomography was used to measure abdominal subcutaneous and visceral adipose tissue, whereas total fat and regional fat (leg, arm, and trunk) were measured by dual energy X‐ray absorptiometry after weight loss and 1 year following the weight loss. Because not all the subjects adhered to the 2 time/week 40 min/day exercise training during the 1‐year follow‐up, subjects were divided into five groups for analysis: aerobic adherers, aerobic nonadherers, resistance adherers, resistance nonadherers, and no exercise. No significant differences were observed between the aerobic training and resistance training adherers for any variable. However, the aerobic (3.1 kg) and resistance (3.9 kg) exercise adherers gained less weight than any of the other three groups (all >6.2 kg). In addition, the two exercise adherence groups did not significantly increase visceral fat (<0.8%) as compared with the 38% increase for the two nonadhering exercise groups and the 25% for the nonexercise group. In conclusion, as little as 80 min/week aerobic or resistance training had modest positive effects on preventing weight regain following a diet‐induced weight loss. More importantly, both aerobic and resistance training prevented regain of potentially harmful visceral fat.     

Respiratory metabolism in patients during exercise therapy in the early period of acute myocardial infarction

Respiratory and cardiocirculatory response to rehabilitation calisthenics in 30 patients, aged 39-66 years, with recent myocardial infarction was studied. Respiratory exchange (Douglas-Haldane method), heart rate, blood pressure, oxygen pulse and electrocardiogram during exercise were investigated. Rehabilitation was performed between the 4th and 21st day of myocardial infarction, in 4 periods with gradually increasing effort, according to the model A designed at the Cardiology Institute in Warsaw. The time of exercises was 10-18 min, depending on the period of rehabilitation. It was found that lung ventilation, tidal volume, oxygen uptake and carbon dioxide output were increased by 20-40% during exercise of the I and II periods of rehabilitation and by 60-100% in the III and IV periods of mobilization. Energy cost of calisthenics rehabilitation was in the lightest case 13 kJ/min. The most increase in respiratory exchange caused exercises performed in sitting position, walking and stair climbing. The last type produced also the highest rise in heart rate (mean 20%) and systolic blood pressure (mean 17% of resting values).     

Effect of aerobic and resistance exercise on central hemodynamic responses in severe chronic heart failure.

Exercise is now considered an important component of management in chronic heart failure (CHF), but little is known about central hemodynamic changes that occur during different exercise modalities in these patients. Seventeen patients (ejection fraction 25 +/- 2%) undertook brachial artery and right heart catheterization and oxygen consumption assessment at rest, during submaximal and peak cycling (Cyc), and during submaximal upper and lower limb resistance exercise. Cardiac output (CO) increased relative to baseline during peak Cyc (P < 0.05) but did not change during submaximal Cyc or upper or lower limb exercise. Heart rate (HR) was lowest during upper limb exercise and progressively increased during lower limb exercise, submaximal Cyc, and peak Cyc, with significant differences between each of these (P < 0.01). Conversely, stroke volume (SV) decreased during submaximal Cyc and lower limb exercise and was lower during peak and submaximal Cyc and lower limb exercise than during upper limb exercise (P < 0.05). CHF patients are dependent on increases in HR to increase CO during exercise when SV may decline. Resistance exercise, performed at appropriate intensity, induces a similar hemodynamic burden to aerobic exercise in patients with CHF.     

Obesity and the Role of Short Duration Submaximal Work on Cardiovascular and Cerebral Hemodynamics

The objective of this study was to compare gas exchange, cardiac and cerebral hemodynamic responses between 10 non-obese and 10 obese men during submaximal work. With the increasing prevalence of obesity, there is a need to understand the impact of obesity on work-induced responses. Participants completed a step-wise incremental cycling until they reached 60% of their age-predicted maximum heart rate. Gas exchange, cardiac and pre-frontal cortex hemodynamic responses were simultaneously measured during rest, work, and recovery. The non-obese group reached ~43% of their predicted maximal aerobic capacity as compared to ~34% in the obese group, with the non-obese working at a relatively higher workload and for more duration than the obese. The obese had elevated baseline heart rate and reduced whole-body oxygen uptake per body weight at baseline and task termination. Other cardiac and cerebral responses, although increased from baseline, were similar between groups during submaximal effort. In the obese, during recovery oxygen uptake and heart-rate recovery were slowest; cardiac output and rate pressure product were greatest, and left ventricle ejection time was shortest. However, both groups exhibited similar cerebral hemodynamics during recovery. These finding imply that, irrespective of their low aerobic fitness, obesity does not impair myocardial performance and cerebrovascular function during graded submaximal work, however, recovery from a short duration of work was influenced by their fitness level. Since a majority of activities of daily living are performed at individual’s submaximal level, understanding influence of obesity on submaximal work is critical.     

Endurance training of older men: responses to submaximal exercise.

The purpose of this study was to quantify the exercise response of older subjects on a time-to-fatigue (TTF) submaximal performance test before and after a training program. Eight older men (67.4 +/- 4.8 yr) performed two maximal treadmill tests to determine maximum oxygen uptake (VO2max) and ventilation threshold (TVE) and a constant-load submaximal exercise treadmill test that required an oxygen uptake (VO2) between TVE and VO2max. The submaximal test, performed at the same absolute work rate before and after the training program, was performed to volitional fatigue to measure endurance time. The men trained under supervision at an individualized pace representing approximately 70% of VO2max (80% maximum heart rate) for 1 h, four times per week for 9 wk. Significant increases were demonstrated for VO2max (ml.kg-1.min-1; 10.6%); maximal ventilation (VE, l/min; 11.6%), and TVE (l/min; 9.8%). Weight decreased 2.1%. Performance time on the TTF test increased by 180% (7.3 +/- 3.0 to 20.4 +/- 13.5 min). The similar end points for VO2, VE, and heart rate during the TTF and maximal treadmill tests established that the TTF test was stopped because of physiological limitations. The increase in performance time among the subjects was significantly correlated with improvements in VO2max and TVE, with the submaximal work rate representing a VO2 above TVE by 88% of the difference between TVE and VO2max pretraining and 73% of this difference on posttraining values.     

The Energy Expenditure of Stair Climbing One Step and Two Steps at a Time: Estimations from Measures of Heart Rate

Stairway climbing provides a ubiquitous and inconspicuous method of burning calories. While typically two strategies are employed for climbing stairs, climbing one stair step per stride or two steps per stride, research to date has not clarified if there are any differences in energy expenditure between them. Fourteen participants took part in two stair climbing trials whereby measures of heart rate were used to estimate energy expenditure during stairway ascent at speeds chosen by the participants. The relationship between rate of oxygen consumption () and heart rate was calibrated for each participant using an inclined treadmill. The trials involved climbing up and down a 14.05 m high stairway, either ascending one step per stride or ascending two stair steps per stride. Single-step climbing used 8.5±0.1 kcal min⁻¹, whereas double step climbing used 9.2±0.1 kcal min⁻¹. These estimations are similar to equivalent measures in all previous studies, which have all directly measured The present study findings indicate that (1) treadmill-calibrated heart rate recordings can be used as a valid alternative to respirometry to ascertain rate of energy expenditure during stair climbing; (2) two step climbing invokes a higher rate of energy expenditure; however, one step climbing is energetically more expensive in total over the entirety of a stairway. Therefore to expend the maximum number of calories when climbing a set of stairs the single-step strategy is better.     

Resistance training improves metabolic economy during functional tasks in older adults

The purpose of this study was to determine the effect resistance training has on metabolic economy during typical activities of daily living in a geriatric population. Twenty-nine men and women (age: 66.7 +/- 4.4 years, body mass: 72.3 +/- 11.9 kg) participated in a 26-week heavy-resistance training program. Before and after training, heart rate and expiratory gases were measured for subjects performing 3 tasks that would mimic common everyday activities encountered by this population: (a) walking (WLK) at 3 miles per hour (4.8 km x h(-1)), (b) carrying a box (CAR) to simulate holding a bag of groceries with 1 hand (30% of maximal isometric strength) while walking at 2 miles per hour (3.2 km x h(-1)), and (c) climbing stairs (STR). No time by gender interaction was observed for the WLK, CAR, and STR activities; consequently, the values for men and women were pooled. Both strength and fat-free mass increased significantly (p < or = 0.001) after the training protocol, whereas body mass remained constant. Oxygen cost decreased significantly by 6% (p < or = 0.05) only for CAR, whereas the respiratory exchange ratio decreased significantly (p < or = 0.05) for both WLK (0.84-0.81) and STR (0.87-0.83), and heart rate decreased significantly (p < or = 0.05) only for CAR. After the resistance training program, subjects also reported a significant decrease (p < or = 0.05) in perceived exertion during performance of all functional task test conditions. These results suggest that a heavy-resistance training program might affect exercise economy during daily tasks and improve ease of physical activity, thereby providing a possible mechanism for increasing quality of life in an older and geriatric population.     

Cardiovascular responses of 70- to 79-yr-old men and women to exercise training

This study determined the effects of endurance or resistance exercise training on maximal O2 consumption (VO2max) and the cardiovascular responses to exercise of 70- to 79-yr-old men and women. Healthy untrained subjects were randomly assigned to a control group (n = 12) or to an endurance (n = 16) or resistance training group (n = 19). Training consisted of three sessions per week for 26 wk. Resistance training consisted of one set of 8-12 repetitions on 10 Nautilus machines. Endurance training consisted of 40 min at 50-70% VO2max and at 75-85% VO2max for the first and last 13 wk of training, respectively. The endurance training group increased its VO2max by 16% during the first 13 wk of training and by a total of 22% after 26 wk of training; this group also increased its maximal O2 pulse, systolic blood pressure, and ventilation, and decreased its heart rate and perceived exertion during submaximal exercise. The resistance training group did not elicit significant changes in VO2max or in other maximal or submaximal cardiovascular responses despite eliciting 9 and 18% increases in lower and upper body strength, respectively. Thus healthy men and women in their 70s can respond to prolonged endurance exercise training with adaptations similar to those of younger individuals. Resistance training in older individuals has no effect on cardiovascular responses to submaximal or maximal treadmill exercise.     

A study of physical demands in riding

Thirteen experienced riders and three elite riders underwent bicycle ergometer tests at submaximal and maximal workloads. Oxygen uptake, pulmonary ventilation and heart rate were also studied during riding at a walk, a trot and a canter. The mean maximal oxygen uptake of the experienced riders in the ergometer test (2.71 . min-1) was superior to the average maximal oxygen uptake of other groups of the same age and sex. The average oxygen uptake of the experienced riders in trot sitting was 1.701 . min-1, trot rising 1.681 . min-1 and in canter 1.801 . min-1. The experienced riders used at least 60% of their maximal aerobic power in trot and canter, which is an exercise intensity that may induce some training effect. Two elite riders consistently had lower oxygen uptakes in riding than the other riders. The heart rate -- oxygen uptake relationships in riding and in the ergometer tests were similar, except during trot sitting when the heart rate tended to be higher, indicating a larger share of static muscle contraction in this gait. Static muscle strength was measured in nine riders and seven non-riders. Six muscle groups were investigated, but no significant difference in muscle strength could be demonstrated between riders and controls.     

Effect of prolonged running on physiological responses to subsequent exercise

The purpose of this study was to compare metabolic and cardiopulmonary responses for submaximal and maximal exercise performed several days preceding (pre-test) and 45 min after (post-test) 21 miles of high intensity (70% VO2 max) treadmill running. Seven aerobically trained subjects' oxygen uptake, oxygen pulse, respiratory exchange ratio, heart rate, pulmonary ventilation, ventilatory equivalent of oxygen, and blood lactate concentration were determined for exercise during the pre- and post-test sessions. No differences were found for submaximal oxygen uptake, oxygen pulse, pulmonary ventilation and ventilatory equivalent of oxygen between the pre- and post-test values. Generally, submaximal heart rate responses were higher, and respiratory exchange ratio values were lower during the post-test. Reductions of maximal work time (12%), maximal oxygen uptake (6%) and maximal blood lactate concentration (47%) were found during the post-test. Thermal stress and glycogen depletion are possible mechanisms which may be responsible for these observed differences.     

Effects of aerobic exercise on serum leptin levels in obese women

It has been demonstrated that leptin concentrations in obese patients may be altered by weight loss. We examined the effects of a 9-week aerobic exercise program on serum leptin concentrations in overweight women (20-50% above ideal body mass) under conditions of weight stability. Sixteen overweight women, mean (SE) age 42.75 (1.64) years, comprised the exercise group which adhered to a supervised aerobic exercise program. A graded exercise treadmill test was conducted before and after the exercise program to determine maximal oxygen uptake (VO2max) using open-circuit spirometry. The women demonstrated improved aerobic fitness (VO2max increased 12.29%), however, body fat and the body mass index did not change significantly [42.27 (1.35)-41.87 (1.33)%]. Fourteen women, age 40.57 (2.80) years, did not exercise over the same time period and served as a control group. Serum leptin levels were not significantly altered for either the exercise [28.00 (2.13)-31.04 (2.71) ng x ml(-1)] or the control group [33.24 (3.78)-34.69 (3.14) ng x mg(-1)]. The data indicate that 9 weeks of aerobic exercise improves aerobic fitness, but does not affect leptin concentrations in overweight women.     

uHIIT显著改善男性减脂效果

本研究旨在探讨以心率控制方式进行12周的上坡高强度间歇训练(uphill high-intensityinterval training,uHIIT)和中等水平强度持续训练(moderate-intensity continuous training, MCT)对于中年过重肥胖男性的身体组成(体脂肪百分比和净体重)、代谢症候指标(安静血压,血糖,高低密度脂蛋白胆固醇,总胆固醇和甘油三脂)及心肺耐力指标(最大摄氧量,无氧阈值和力竭时间)的影响。本研究通过对25位中年过重肥胖男性(BMI>24)训练前后的身体组成与代谢症候指标进行检测,并进行渐增强度测验,以评估心肺耐力指标。前测后,受试者随机分配至uHIIT组(心率控制强度为90%HRmax,运动2 min休息1 min共7次进行约20 min)、MCT组(心率控制强度为65%～70%HR_max,运动约40 min)与控制组。进行每周3次为期12周的训练后,再接受相同的测试1次。研究显示,相较于控制组,uHIIT组与MCT组的最大摄氧量(V4O_2max)、无氧阈值、力竭时间、臀部脂肪皆显著改善,且uHIIT组在V4O_2max增加量上显著高于MCT组,仅有uHIIT组的血压、体脂肪百分比和腿部脂肪显著改善。本研究表明,uHIIT与MCT皆可改善中年肥胖男性心肺耐力,同时uHIIT对于减脂与血压的改善较为显著,但其余代谢指标受到运动的影响较小,减脂效果上uHIIT的运动效益优于MCT,建议运动时应重视运动强度。     

Endurance training in older men and women II. Blood lactate response to submaximal exercise

Seven men and four women (age 63 +/- 2 yr, mean +/- SD, range 61-67 yr) participated in a 12-mo endurance training program to determine the effects of low-intensity (LI) and high-intensity (HI) training on the blood lactate response to submaximal exercise in older individuals. Maximal oxygen uptake (VO2max), blood lactate, O2 uptake (VO2), heart rate (HR), ventilation (VE), and respiratory exchange ratio (R) during three submaximal exercise bouts (65-90% VO2max) were determined before training, after 6 mo of LI training, and after an additional 6 mo of HI training. VO2max (ml X kg-1 X min-1) was increased 12% after LI training (P less than 0.05), while HI training induced a further increase of 18% (P less than 0.01). Lactate, HR, VE, and R were significantly lower (P less than 0.05) at the same absolute work rates after LI training, while HI training induced further but smaller reductions in these parameters (P greater than 0.05). In general, at the same relative work rates (ie., % of VO2max) after training, lactate was lower or unchanged, HR and R were unchanged, and VO2 and VE were higher. These findings indicate that LI training in older individuals results in adaptations in the response to submaximal exercise that are similar to those observed in younger populations and that additional higher intensity training results in further but less-marked changes.     

Effect of calcium channel blockade and beta-adrenoceptor blockade on short graded and single-level endurance exercises in normal men

The effect of verapamil (240 mg) on exercise capacity was studied during a short graded and a single-level endurance exercise test in 12 normal volunteers; it was compared to the effects of atenolol (100 mg x day-1). Intake of verapamil, atenolol and placebo, administered according to a randomized, double-blind cross-over design, was started 3 days before the exercise tests. Compared to placebo, verapamil did not affect peak oxygen uptake in the graded test or exercise duration in the endurance test. Heart rate, systolic blood pressure, rating of perceived exertion and respiratory data at submaximal and peak exercise were unaffected in either test. On the other hand atenolol reduced maximal oxygen uptake by 5% (p less than 0.001) and endurance exercise duration by 17% (p less than 0.05). Besides marked decreases in heart rate and systolic blood pressure during the two types of exercise, atenolol also reduced oxygen uptake at submaximal exercise levels and it increased the rating of perceived exertion (p less than 0.05), the latter only during the endurance exercise test.     

Relation of heart rate to percent VO2 peak during submaximal exercise in the heat.

We tested the hypothesis that elevation in heart rate (HR) during submaximal exercise in the heat is related, in part, to increased percentage of maximal O(2) uptake (%Vo(2 max)) utilized due to reduced maximal O(2) uptake (Vo(2 max)) measured after exercise under the same thermal conditions. Peak O(2) uptake (Vo(2 peak)), O(2) uptake, and HR during submaximal exercise were measured in 22 male and female runners under four environmental conditions designed to manipulate HR during submaximal exercise and Vo(2 peak). The conditions involved walking for 20 min at approximately 33% of control Vo(2 max) in 25, 35, 40, and 45 degrees C followed immediately by measurement of Vo(2 peak) in the same thermal environment. Vo(2 peak) decreased progressively (3.77 +/- 0.19, 3.61 +/- 0.18, 3.44 +/- 0.17, and 3.13 +/- 0.16 l/min) and HR at the end of the submaximal exercise increased progressively (107 +/- 2, 112 +/- 2, 120 +/- 2, and 137 +/- 2 beats/min) with increasing ambient temperature (T(a)). HR and %Vo(2 peak) increased in an identical fashion with increasing T(a). We conclude that elevation in HR during submaximal exercise in the heat is related, in part, to the increase in %Vo(2 peak) utilized, which is caused by reduced Vo(2 peak) measured during exercise in the heat. At high T(a), the dissociation of HR from %Vo(2 peak) measured after sustained submaximal exercise is less than if Vo(2 max) is assumed to be unchanged during exercise in the heat.     

Exercise training enhances leg vasodilatory capacity of 65-yr-old men and women

To determine whether extremity vasodilatory capacity may be augmented in older persons by endurance exercise training, lower leg blood flow and conductance were characterized plethysmographically at rest and during maximal hyperemia in 9 men and 10 women aged 64 +/- 3 (SD) yr before and after 31 +/- 6 wk of walking and jogging at 70-90% of maximal oxygen uptake for 45 min 3-5 days/wk. Maximal oxygen uptake expressed as milliliters per kilogram per minute improved 25% in men and 21% in women (P less than 0.01). Maximal leg blood flow and conductance increased in all nine men by an average of 39 +/- 33 (P less than 0.001) and 42 +/- 44% (P less than 0.004), respectively. Results were more variable in women and achieved unequivocal statistical significance only for maximal blood flow (+33 +/- 54% for blood flow and +29 +/- 55% for conductance; P less than 0.02 and P = 0.05, respectively). Body weight and skinfold adiposity declined in both sexes (P less than 0.05). Enhancement of vasodilatory capacity was related to weight loss in men and adipose tissue loss in women (r = 0.61 and 0.51, respectively; P less than 0.05). There were no significant changes in exercise capacity, body weight, or maximal blood flow in four male and three female controls aged 66 +/- 4 yr. Thus adaptability of the lower limb circulation to endurance exercise training is retained to at least age 65 yr.     

Effects of aerobic exercise on metabolic syndrome improvement in response to weight reduction

Objective: The objective was to test effects of aerobic exercise training on metabolic syndrome (MetSyn) improvement in response to weight reduction. Research Methods and Procedures: A total of 459 overweight and obese women (age, 49 ± 9 years; BMI, 28 ± 3 kg/m²) were recruited for a baseline examination to test the relationship between cardiorespiratory fitness and metabolic syndrome prevalence; among these, 67 subjects with MetSyn were treated with 14‐week weight‐loss programs, which included low‐calorie diet and aerobic exercise. The MetSyn was defined according to the Examination Committee of Criteria for “Metabolic Syndrome” in Japan. Maximal oxygen uptake (V?o _2max) during a maximal cycling test was measured as an index of cardiorespiratory fitness at baseline and after the intervention. Results: In the baseline examination, age‐ and BMI‐adjusted odds ratios for MetSyn prevalence in the low, middle, and upper thirds of V?o _2max were 1.0 (referent), 0.50 (95% confidence interval, 0.26 to 0.95), and 0.39 (95% confidence interval, 0.14 to 0.96), respectively (linear trend, p = 0.02). The adjusted odds ratios for MetSyn improvement in the two interventions with diet alone and diet plus exercise were 1.0 and 3.68 (95% confidence interval, 1.02 to 17.6; p = 0.04), respectively. Discussion: These results suggest that adding aerobic exercise training to a dietary weight‐reduction program further improves MetSyn (adjusted odds ratio, 3.68) in obese women, compared with diet alone. Further studies on an association between V?o _2max change and MetSyn improvement are needed.