The effect of cardiorespiratory fitness and obesity on cancer mortality in women and men

PURPOSE: The purpose of this study was to determine the independent and combined effects of cardiorespiratory fitness and obesity on all-cause cancer mortality for women and men. METHODS: Using the Lipids Research Clinics Prevalence Study, we examined the relationship of fitness and obesity on cancer mortality among 2585 women and 2890 men followed from 1972-1976 to 1998. Cardiorespiratory fitness was measured using a treadmill test and obesity was assessed using body mass index (BMI) calculated from measured height and weight. Gender-specific hazard ratios (HR) were calculated from proportional hazard models, which included covariates for age, education, smoking, alcohol intake, Keys score, and menopause (women only). RESULTS: Adjusted cancer mortality was significantly lower in the most fit quintile relative to the other four quintiles for men (HR = 0.47; 95% CI, 0.27-0.81) but not for women (HR = 0.84; 95% CI, 0.52-1.36). Adjusted cancer mortality was significantly higher in the highest BMI quintile relative to the other four BMI quintiles for women (HR = 1.49; 95% CI, 1.06-2.09) but not for men (HR = 1.05; 95% CI, 0.77-1.43). Further adjustment for BMI on fitness and adjustment for fitness on BMI did not meaningfully change the HR. There were no significant interactions between fitness and obesity in predicting cancer mortality for either women or men. CONCLUSION: In this study, high fitness was a stronger predictor of cancer mortality in men, whereas high BMI was a stronger predictor of cancer mortality in women.     

Characterizing body composition,cardiorespiratory fitness,and physical activity in women with anterior cruciate ligament reconstruction

ObjectivesThe purpose was to compare body composition, cardiorespiratory fitness, and physical activity (PA) engagement between women with ACLR and healthy controls.DesignCross-sectional study.SettingUniversity laboratory.ParticipantsTen women with ACLR (time since surgery = 33.0 ± 18.3 months; age = 21.4 ± 3.8 years) and 10 healthy women (age = 21.9 ± 3.1 years) matched based on age (±2 years) and Tegner Activity Level (±2) participated.Main outcome measuresBody fat percentage (%BF) was estimated using air displacement plethysmography, cardiorespiratory fitness was assessed via a graded cycle test, and PA was assessed using accelerometers worn for 7 days. Groups were compared using Mann-Whitney U tests. Time (minutes/week) spent in moderate-to-vigorous PA and step count (steps/day) were compared between groups using a one-way ANCOVA with 7-day total wear time as the only covariate. Statistical significance was established a priori as α ≤ 0.05.ResultsWomen with ACLR had significantly higher %BF than controls (ACLR = 32.7 ± 6.7%, healthy = 22.6 ± 4.9%; p < 0.01) and participated in less steps per day (ACLR = 6650 ± 3227 steps/day, healthy = 9361 ± 2626 steps/day; p = 0.02).ConclusionsThere may be persistent negative effects on body composition and PA engagement for women following ACLR. Low PA and high %BF have adverse consequences for premature mortality and morbidity; therefore, it is crucial to assess these characteristics and determine interventions to maintain PA and healthy body composition following ACLR.     

Relationship between cardiorespiratory fitness,body composition and blood pressure in school children

BACKGROUND: The purpose of this comparative and correlational cross-sectional study was to describe the associations between cardiorespiratory fitness, blood pressure and body composition in Portuguese school children. METHODS: The sample comprised 529 children (246 males and 283 females) aged 8-15 years-old. Body height and body mass were determined by standard anthropometric METHODS: Blood pressures were measured with children sitting after at least 5 min rest. The maximal multistage 20 m shuttle run test was carried-out to predict maximal aerobic power. RESULTS: The present study shows that boys were more fit (p= or <0.05) and less fat than girls (p= or <0.05). Multiple regression analysis reveals that weight and age explained significantly (p= or <0.01) the amounts of systolic blood pressure (SBP) and diastolic blood pressure (DBP). In girls, percentage of fat (%F) showed an influence on the variance in SBP (4.9%, p= or <0.05). In addition, weight (14.5%) and age (9.8%) account significantly (p= or <0.01) for the amount of variance to DBP in males. For girls, age (11.4%) and BMI (2.4%) account significantly to the variance found in DBP. However, the independent variables, for both sexes, account less than 50% of the overall variance found in blood pressures values. CONCLUSIONS: In conclusion, the present study shows that boys were more fit and had less fat than girls. The level of cardiorespiratory fitness does not seem to be an important correlate of blood pressure variation across age groups and gender.     

Water-based training enhances both physical capacities and body composition in healthy young adult women

Purpose

The purpose of this study was to determine the effectiveness of a 9 weeks aquatic training program on aerobic capacity, muscle strength, flexibility, balance and body composition in 34 healthy young adult women.

Methods

Five typical water based exercises (WE) of known intensity were utilized during the classes; intensity ranged from “moderate” to “hard” according to ACSM criteria (RPE range 12–14).

Results

The group physical activity level and food intake were not significantly different before and after training. A significant decrease for the skin folds sum (?4.6 %) and for %fat mass (?3.8 %) calculated according to skin folds technique was found after training. DXA regional data showed a significant increase in the fat-free mass of arms (2.4 %) and trunk (0.9 %). According to the Astrand step test, the training program led to an increase of estimated maximal oxygen uptake (14.9 %) and a decrease in sub-maximal Heart Rate (?6.9 %). A significant change in the majority of the physical capacities tested was found: abdominal and upper body muscular endurance (21 and 36 %, respectively), leg flexors and extensors maximal strength (12 and 8 %, respectively) as well as balance (34 %) all improved after training (p < 0.05)

Conclusions

A training program based on WE of known intensity and tailored to the ACSM recommendations can significantly improve cardio respiratory fitness, muscular endurance, strength, balance and some aspects of body composition in active young adult women.

     

Weight training and strength, cardiorespiratory functioning and body composition of men.

Forty-five men (18-35 years) trained three times a week for eight weeks to determine the effects of four constant-resistant weight training programmes on muscular strength, endurance, body composition and cardiovascular functioning. Subjects were randomly assigned to one of four programmes: Endurance (2 sets of 15 repetition maximum [RM]); Explosive (1 set of 15 RM); Strength 1 (3 sets of 6 RM); Strength 2 (1 set of 10 RM twice weekly and 1 set of 3 RM once weekly). All groups showed significant increases in elbow and shoulder flexion strength with elbow extension strength improved in the Explosive, Strength 2 and Endurance groups. Shoulder extension strength improved the Endurance group and in the Strength 2 group. Maximum oxygen uptake (L/min) and (ml X kg-1 min-1) improved significantly in the Endurance and Strength 2 groups. Lean body weight increased significantly in all groups except the Strength 1 group, but there was no change in % fat for any group. Due to a high drop out rate (55%) and injury related problems, the Explosive technique is not recommended. The Endurance and Strength 2 programmes were most effective for improving physiologic functioning, as assessed in this study.     

The effect of performance feedback on cardiorespiratory fitness field tests

We investigated the effects of performance feedback (PF) on predicting maximal oxygen uptake (VO2 max) using the 20 m Multistage Shuttle Run Test (MST) and 20 m Square Shuttle Test (SST). The agreement between these two field tests in relation to laboratory VO2 max was also examined. Forty healthy males (age: 21.5+/-2.3; BMI: 23.7+/-2.0) randomly performed four indirect VO2 max tests; that is the MST and SST, as well as a modified version of MST (MSTMD) and SST (SSTMD). During MST and SST subjects received PF with respect to both test stage and running pace. In contrast, MSTMD and SSTMD incorporated auditory feedback which solely emitted signals regulating the running pace. Participants also performed a laboratory VO2 max treadmill test (TT). ANOVA demonstrated significant mean predicted VO2 max decrements in both MSTMD (p<0.001) and SSTMD (p<0.05) compared to MST and SST, respectively. In predicting TTVO2 max, the '95% limits of agreement' analysis indicated errors equal to 3.6+/-9.6 and 1.4+/-10.3 ml kg-1 min-1 with coefficients of variation of +/-10.0% and +/-10.9%, for MST and MSTMD, respectively. The corresponding '95% limits of agreement' values for SST and SSTMD were 0.1+/-5.0 and -1.1+/-6.1 ml kg-1 min-1 with coefficients of variation of +/-5.4% and +/-6.7%, respectively. It is concluded that the application of PF leads to superior field testing performances.     

Effects of training on cardiorespiratory fitness and lipidic profile of paraplegics

This study investigated the effects of training on cardiorespiratory fitness and lipidic profile of 20 paraplegics (10 sedentary men aged 34±7 years and 10 active men aged 37±7 years). Active men performed sporting activities such as athletics and wheelchair basketball. Pulmonary function (forced vital capacity (FCV) and forced expired volume (FEV₁)) were measured at rest. An incremental test (increase of 2 km/h every load) was then performed until volitional exhaustion on a wheelchairroller ergometer. During the last minute of each speed, heart rate (HR), oxygen consumption ( $ \dot V $ O₂) and pulmonary ventilation ( $ \dot V $ E) were determined. Moreover, blood samples were taken, at rest and fasting, for lipidic and lipoproteic profile analysis. The peak $ \dot V $ O₂ value was significantly higher in active vs. sedentary men (19.1±4.3 vs. 12.8±3.1 ml · min^?1 · kg^?1). Moreover, active men sustained a greater maximal leed (7.7±0.9 vs. 4.8±1.4 km/h). FEV₁ (4.09±0.52 vs. 2.80±0,58 l · min^?1), FCV (4.96±0.61 vs. 2.92±0.45 l · min^?1) and HDL cholesterol (59.3±11.2 vs. 36.6±8.3 mg/dl) were remarkably higher in active men. Total cholesterol (158.0±21.4 vs. 198.6±20.3 mg/dl) and LDL cholesterol (101.6±24.2 vs. 143.1±26.1 mg/dl) were significantly lower in active men. Training allows paraplegics to reach and maintain a good degree of cardiorespiratory fitness and to improve lipidic and lipoproteic blood profiles, despite their hypomotility. This helps them counteract the well known increased risk of coronary artery disease and respiratory disease mortality in these subjects.     

The influence of somatotype on anthropometric prediction of body composition in young women

The influence of somatotype on the validity of anthropometric prediction of body density (Db) in young women (N = 92) was investigated. Three groups of predominantly endomorph (N = 27), mesomorph (N = 35), and ectomorph (N = 30) women were identified by the Heath-Carter and Sheldon somatotyping methods. Discriminant analysis revealed a 100% accuracy in somatotype group determination. Thirteen diameters, 26 girths, and 8 skinfolds were measured and used in a STEPWISE regression analysis to derive somatotype-specific regression equations to predict body density. Combining all the measures provided very good prediction accuracy in all three groups with multiple correlation coefficients (R) of 0.98, 0.90, and 0.90, and the standard error of estimate (SEE) of 0.003, 0.005, and 0.005 for Db (gm X cc-1) in the endomorphs, mesomorphs, and ectomorphs, respectively. A cross-validation study confirmed the accuracy of the somatotype-specific regression equations and demonstrated an inherent weakness in using some generalized equations on specific somatotypes. The use of non-somatotype-specific equations resulted in mean Db prediction errors ranging from -0.018 to +0.023 gm X cc-1 (8.5 to -10.7% Fat). Although all equations tested demonstrated specific weaknesses in one or more of the somatotype groups when predicting Db, the Jackson et al. (1980) equation performed better than most of the non-somatotype-specific prediction equations. These findings suggest that the anthropometric estimation of Db may not be sample specific in the same manner as had been previously thought and that greater accuracy may be achieved by using regression equations which have been generated on a previously somatotyped population sample.     

Effect of high cardiorespiratory fitness and high body fat on insulin resistance

PURPOSE: High cardiorespiratory fitness (CRF) dramatically lowers risk for cardiometabolic disease in overweight and obese individuals. This effect is likely attributable to the inverse relationship between high CRF and insulin resistance. In this study, the independent effects of high body fat and high CRF on insulin resistance were assessed. METHODS: The blood glucose and insulin responses to an oral glucose tolerance test were measured in 10 overweight women with high CRF (OF), 9 lean women with high CRF (LF), and 10 overweight women with low CRF (OU). RESULTS: Fasting plasma glucose (P = 0.77), insulin (P = 0.23), and triacylglycerol (P = 0.99) concentrations were similar between OF and LF, with mean values in both groups lower than in OU. The glucose area under the curve (AUC) was not different between LF and OF (P = 0.28) and was significantly higher in OU. Insulin sensitivity, estimated from the composite insulin-sensitivity index (C-ISI), was slightly but significantly lower in OF compared with LF. Similarly, insulin AUC was 43% lower in LF compared with OF, although this difference was not statistically significant (P = 0.08). Insulin AUC was 50% higher (P = 0.04) and C-ISI was 35% lower (P = 0.09) in OU compared with OF. CONCLUSION: Compared with lean fit women, estimated insulin sensitivity was only slightly lower and plasma triacylglycerols were almost identical in overweight women with equally high CRF despite a twofold elevation in body fat percentage.     

Effects of CrossFit training on lipid profiles,body composition and physical fitness in overweight men

Sport Sciences for Health - The aim of this study was to investigate the influence of the CrossFit training on cardiovascular risk factors in overweight men. Twenty-six overweight men (age,...     

Training effects of short bouts of stair climbing on cardiorespiratory fitness, blood lipids, and homocysteine in sedentary young women

Objectives: To study the training effects of eight weeks of stair climbing on VO₂MAX, blood lipids, and homocysteine in sedentary, but otherwise healthy young women. Methods: Fifteen women (mean (SD) age 18.8 (0.7) years) were randomly assigned to control (n = 7) or stair climbing (n = 8) groups. Stair climbing was progressively increased from one ascent a day in week 1 to five ascents a day in weeks 7 and 8. Training took place five days a week on a public access staircase (199 steps), at a stepping rate of 90 steps a minute. Each ascent took about two minutes to complete. Subjects agreed not to change their diet or lifestyle over the experimental period. Results: Relative to controls, the stair climbing group displayed a 17.1% increase in VO₂MAX and a 7.7% reduction in low density lipoprotein cholesterol (p<0.05) over the training period. No change occurred in total cholesterol, high density lipoprotein cholesterol, triglycerides, or homocysteine. Conclusions: The study confirms that accumulating short bouts of stair climbing activity throughout the day can favourably alter important cardiovascular risk factors in previously sedentary young women. Such exercise may be easily incorporated into the working day and therefore should be promoted by public health guidelines.     

The interactions of intensity, frequency and duration of exercise training in altering cardiorespiratory fitness

This review has grouped many studies on different populations with different protocols to show the interactive effects of intensity, frequency and duration of training as well as the effects of initial fitness levels and programme length on cardiorespiratory fitness as reflected by aerobic power (VO2max). Within each level of exercise duration, frequency, programme length or initial fitness level, the greatest improvements in aerobic power occur when the greatest challenge to aerobic power occurs i.e., when intensity is from 90 to 100% of VO2max. The pattern of improvement where different intensities are compared with different durations suggests that when exercise exceeds 35 minutes, a lower intensity of training results in the same effect as those achieved at higher intensities for shorter durations. Frequencies of as low as 2 per week can result in improvements in less fit subjects but when aerobic power exceeds 50 ml/kg/min, exercise frequency of at least 3 times per week is required. As the levels of initial fitness improve, the changes in aerobic power decreases regardless of the intensity, frequency or duration of exercise. Although these pooled data suggest that maximal gains in aerobic power are elicited with intensities between 90 to 100% VO2max, 4 times per week with exercise durations of 35 to 45 minutes, it is important to note that lower intensities still produce effective changes and reduce the risks of injury in non-athletic groups.     

Rebounding exercise. Are the training effects sufficient for cardiorespiratory fitness?

Additional research is needed in order to document the effects of rebound training. Efforts should focus on the factors that are necessary for standardising the intensity of exercise such as step height and frequency. In addition, attention may be given to alternative methods of increasing exercise intensity while rebounding. One such method may be to increase the total muscle mass involved by adding the pumping of handheld weights to the rebounding exercise. Data from our laboratory (Bishop et al. 1986) has demonstrated that the addition of pumping 1-, 2- and 3-pound (0.45, 0.91 and 1.36 kg) handheld weights, at 2- and 3-foot (30 and 45 cm) heights, to rebounding exercise will increase the oxygen requirement from 26 to 60%. Assessing these effects in a training study would necessitate testing for adaptation in the upper extremities. This type of training highlights the need for activity specific tests. More specifically, additional research is needed to: 1. Determine the energy cost of activities other than jogging/bouncing that may be possible on a mini-trampoline, such as those described by White (1984). 2. Determine the training response of subjects in studies in which the controllable factors affecting intensity are standardised. 3. Examine the effects of longer periods of rebound training. Because rebounding exercise is novel to most subjects, it would appear that the length of training should allow subjects to maintain a reasonable frequency, intensity, and duration of exercise above that needed for familiarization with the new activity. 4. Determine if the prolonged use of other training aids (limb weights) with rebounding is feasible and effective in long term training.(ABSTRACT TRUNCATED AT 250 WORDS)     

Body composition and cardiorespiratory fitness indicators in prepubescent boys and girls.

Abstract.Relations between frequently used indicators of cardiorespiratory fitness, sex and body composition were studied in a birth-cohort based sample of young prepubescent children (age range: 6.8 - 8.2 years). The Bruce treadmill test was used to assess submaximal heart rate, endurance time (ET), calculated total work (W(total)) and maximal power output (P(max)) in 100 children (50 boys, 50 girls). Body composition was determined by skinfold measurements. In 17 children, maximal oxygen consumption was measured. Percent body fat was negatively associated with ET and relative oxygen uptake (ml x min(-1) x kg(-1)) and was positively related to submaximal heart rate at 6 minutes exercise (HR6). Fat-free mass was positively related to W(total), P(max) and absolute oxygen uptake (ml x min(-1)). Relative oxygen uptake (ml x min(-1) x kg(-1)) was related to ET. Absolute oxygen uptake (ml x min(-1)) was related to W(total) and P(max). The observed differences in indicators of cardiorespiratory fitness between boys and girls were largely attributable to a difference in body composition. The results further demonstrate that when oxygen uptake measurement is not feasible, W(total) or P(max) (expressed per kilogram fat-free mass) seem to provide better indicators of aerobic power than endurance time.