title: Relationship between low cardiorespiratory fitness and mortality in normal-weight, overweight, and obese men. Diet, physical activity, and sedentary behaviors as risk factors for overweight in adolescence. Relations of moderate and vigorous physical activity to fitness and fatness in adolescents. The Association between Cardiorespiratory Fitness and Impaired Fasting Glucose and Type 2 Diabetes Mellitus in Men Objectively measured daily physical activity related to aerobic fitness in young children
abstract: CONTEXT Recent guidelines for treatment of overweight and obesity include recommendations for risk stratification by disease conditions and cardiovascular disease ( CVD ) risk factors , but the role of physical inactivity is not prominent in these recommendations . OBJECTIVE To quantify the influence of low cardiorespiratory fitness , an objective marker of physical inactivity , on CVD and all-cause mortality in normal-weight , overweight , and obese men and compare low fitness with other mortality predictors . DESIGN Prospect i ve observational data from the Aerobics Center Longitudinal Study . SETTING Preventive medicine clinic in Dallas , Tex . PARTICIPANTS A total of 25714 adult men ( average age , 43.8 years [ SD , 10.1 years ] ) who received a medical examination during 1970 to 1993 , with mortality follow-up to December 31 , 1994 . MAIN OUTCOME MEASURES Cardiovascular disease and all-cause mortality based on mortality predictors ( baseline CVD , type 2 diabetes mellitus , high serum cholesterol level , hypertension , current cigarette smoking , and low cardiorespiratory fitness ) stratified by body mass index . RESULTS During the study period , there were 1025 deaths ( 439 due to CVD ) during 258781 man-years of follow-up . Overweight and obese men with baseline CVD or CVD risk factors were at higher risk for all-cause and CVD mortality compared with normal-weight men without these predictors . Using normal-weight men without CVD as the referent , the strongest predictor of CVD death in obese men was baseline CVD ( age- and examination year-adjusted relative risk [ RR ] , 14.0 ; 95 % confidence interval [ CI ] , 9.4 - 20.8 ) ; RRs for obese men with diabetes mellitus , high cholesterol , hypertension , smoking , and low fitness were similar and ranged from 4.4 ( 95 % CI , 2.7 - 7.1 ) for smoking to 5.0 ( 95 % CI , 3.6 - 7.0 ) for low fitness . Relative risks for all-cause mortality in obese men ranged from 2.3 ( 95 % CI , 1.7 - 2.9 ) for men with hypertension to 4.7 ( 95 % CI , 3.6 - 6.1 ) for those with CVD at baseline . Relative risk for all-cause mortality in obese men with low fitness was 3.1 ( 95 % CI , 2.5 - 3.8 ) and in obese men with diabetes mellitus 3.1 ( 95 % CI , 2.3 - 4.2 ) and as slightly higher than the RRs for obese men who smoked or had high cholesterol levels . Low fitness was an independent predictor of mortality in all body mass index groups after adjustment for other mortality predictors . Approximately 50 % ( n = 1674 ) of obese men had low fitness , which led to a population -attributable risk of 39 % for CVD mortality and 44 % for all-cause mortality . Baseline CVD had population attributable risks of 51 % and 27 % for CVD and all-cause mortality , respectively . CONCLUSIONS In this analysis , low cardiorespiratory fitness was a strong and independent predictor of CVD and all-cause mortality and of comparable importance with that of diabetes mellitus and other CVD risk factors BACKGROUND The proportion of overweight adolescents has increased , but the behavioral risk factors for overweight youth are not well understood . OBJECTIVE To examine how diet , physical activity , and sedentary behaviors relate to overweight status in adolescents . DESIGN AND SETTING Baseline data from the Patient-Centered Assessment and Counseling for Exercise Plus Nutrition Project , a r and omized controlled trial of adolescents to determine the effects of a clinic-based intervention on physical activity and dietary behaviors . PARTICIPANTS A total of 878 adolescents aged 11 to 15 years , 42 % of whom were from minority background s. MAIN OUTCOME MEASURE Centers for Disease Control and Prevention body mass index-for-age percentiles divided into 2 categories : normal weight ( < 85th percentile ) and at risk for overweight plus overweight ( AR + O ) ( > or=85th percentile ) . RESULTS Overall , 45.7 % of the sample was classified as AR + O with a body mass index for age at the 85th percentile or higher . More girls from minority background s ( 54.8 % ) were AR + O compared with non-Hispanic white girls ( 42 % ) ( chi(2)(1 ) = 7.6 ; P = .006 ) . Bivariate analyses indicated that girls and boys in the AR + O group did fewer minutes per day of vigorous physical activity , consumed fewer total kilojoules per day , and had fewer total grams of fiber per day than those in the normal-weight group . Boys in the AR + O group also did fewer minutes per day of moderate physical activity and watched more minutes per day of television on nonschool days than normal-weight boys . Final multivariate models indicated that independent of socioeconomic status ( as assessed by household education level ) , girls had a greater risk of being AR + O if they were Hispanic or from another minority background ( odds ratio [ OR ] = 1.65 ; 95 % confidence interval [ CI ] , 1.09 - 2.49 ) and a reduced risk of being AR + O as minutes per day of vigorous physical activity increased ( OR = 0.93 ; 95 % CI , 0.89 - 0.97 ) . A low level of vigorous physical activity was the only significant risk factor for boys being AR + O ( OR = 0.92 ; 95 % CI , 0.89 - 0.95 ) . Analyses based on meeting behavioral guidelines supported these findings and showed that failing to meet the 60 min/d moderate to vigorous physical activity guideline was associated with overweight status for both girls and boys . In addition , boys who failed to meet sedentary behavior and dietary fiber guidelines were more likely to be overweight . CONCLUSIONS Of the 7 dietary and physical activity variables examined in this cross-sectional study , insufficient vigorous physical activity was the only risk factor for higher body mass index for adolescent boys and girls . Prospect i ve studies are needed to clarify the relative importance of dietary and physical activity behaviors on overweight in adolescence BACKGROUND It is unclear how moderate and vigorous intensities of physical activity ( PA ) are associated with cardiovascular fitness ( CVF ) and percentage of body fat ( % BF ) in adolescents . OBJECTIVE We tested the hypothesis that vigorous PA , to a greater degree than moderate PA , would be associated with better CVF and lower % BF . DESIGN This was a cross-sectional study of 421 black and white high school students ( x age : 16 y ) .  PA was measured with 5 d of accelerometry and expressed in min/d of moderate or vigorous PA .  CVF was measured with a multistage treadmill test and was expressed as the oxygen consumption at a heart rate of 170 bpm . % BF was measured with dual-energy X-ray absorptiometry . Multiple regressions were used to determine the degree to which variance in CVF and % BF was explained by PA , after control for age , sex , race , and the sex x race interaction . RESULTS A higher index for CVF was associated with higher amounts of moderate and vigorous PA ;  more variance was explained by vigorous than by moderate PA .  Lower % BF was associated with higher amounts of vigorous PA but not with the amount of moderate PA . CONCLUSION Black and white adolescents who engaged in relatively large amounts of free-living vigorous exercise were likely to be relatively fit and lean Type 2 diabetes is a common disease in industrialized countries . It is a major cause of cardiovascular disease and all-cause mortality ( 1 - 6 ) , and its prevalence has increased continuously over the past few decades ( 1 ) . The American Diabetes Association currently defines impaired fasting glucose as a fasting plasma glucose level from 6.1 to 6.9 mmol/L ( 110 to 125 mg/dL ) and type 2 diabetes as a fasting plasma glucose level of 7.0 mmol/L ( 126 mg/dL ) or more ( 1 ) . Data from several prospect i ve studies show an inverse association between physical activity and diabetes ( 7 - 13 ) . However , these studies are limited by the use of self-reporting of physical activity and presence of type 2 diabetes ( 7 - 12 ) . Self-reporting of physical activity tends to be imprecise , and type 2 diabetes is undiagnosed in about 50 % of the prevalent cases ( 14 ) . This leads to misclassification on both exposure and outcome measures ( 15 ) . These limitations may result in underestimation of the true association between sedentary habits and risk for type 2 diabetes . Impaired fasting glucose is a strong predictor of type 2 diabetes , cardiovascular disease , and other diabetic complications ( 6 , 16 - 18 ) . The underlying cause of impaired fasting glucose is unknown , and no prospect i ve study of the association between physical activity and impaired fasting glucose has been published . We examined the relation of cardiorespiratory fitness , objective ly determined by a maximal exercise test on a treadmill , to the incidence of impaired fasting glucose and type 2 diabetes . Cases of impaired fasting glucose and diabetes at baseline and follow-up were determined by using the American Diabetes Association 's current guidelines ( 1 ) . Methods Patients In our population -based prospect i ve study , we included 8633 men 30 to 79 years of age at baseline ( mean , 43.5 years ) who completed at least two medical evaluations at the Cooper Clinic in Dallas , Texas , from 1970 to 1995 . Patients come to the Cooper Clinic for preventive medical examinations and health promotion counseling . Many are sent by their employers for these services , some are referred by their personal physicians , and others are self-referred . More than 97 % of the patients are white , and most are employed in executive or professional occupations . More than 75 % are college graduates . Although study participants came from middle and upper socioeconomic strata , they were similar to other well-characterized population -based cohorts in terms of blood pressure , cholesterol level , body weight , and cardiorespiratory fitness ( 19 ) . The study was review ed and approved annually by the institutional review board at the Cooper Institute for Aerobics Research . Additional details of the study methods and population characteristics of the cohort have been published elsewhere ( 20 , 21 ) . Because clinical or sub clinical heart disease and other conditions associated with type 2 diabetes may alter the level of physical activity and thus cardiorespiratory fitness , we excluded men with an abnormal resting or exercise electrocardiogram or a history of heart attack , stroke , or cancer at the baseline clinical examination ( n=2350 ) . The baseline evaluation was performed after participants gave written informed consent for the initial medical examination and registration in the follow-up study . Examinations were done after patients had fasted for at least 12 hours and included personal and family health histories , a question naire on demographic characteristics and health habits  , a  physical examination  , an  exercise test , anthropometric measurement , electrocardiography , blood chemistry analyses , and blood pressure measurement . Technicians who followed a st and ard manual of operations administered all procedures . Impaired fasting glucose and type 2 diabetes were diagnosed according to American Diabetes Association criteria that define impaired fasting glucose as a fasting plasma glucose level of 6.1 to 6.9 mmol/L ( 110 mg/dL to 125 mg/dL ) and diabetes as a fasting plasma glucose level of 7.0 mmol/L ( 126 mg/dL ) or more ( 1 ) . Patients who did not meet these criteria but who reported a history of diabetes or current therapy with oral antidiabetic agents or insulin were also considered to have diabetes . We excluded patients who had diabetes at baseline according to any of these criteria ( n=377 ) .  Cardiorespiratory fitness was assessed with a maximal exercise test that followed a modified Balke protocol ( 22 ) . Details of treadmill speed and elevation have been described elsewhere ( 20 , 21 ) . Briefly , the test began with the patient walking on a horizontal treadmill at 88 m/min . After the first minute , the elevation increased to 2 % ; the elevation then increased 1 % each minute up to 25 minutes . For the few patients who were still able to continue , the elevation was held constant after 25 minutes and the speed was increased by 5.4 m/min until the patient reached volitional fatigue . Use of this protocol for the exercise test correlates highly ( r=0.92 ) with measured maximal oxygen uptake ( 23 ) . All patients in our study achieved at least 85 % of their age-predicted maximal heart rate ; average maximal heart rates ( SD ) in each age group were 186 11 beats/min for patients 30 to 39 years of age , 179 12 beats/min for those 40 to 49 years of age , 172 13 beats/min for those 50 to 59 years of age , and 162 17 beats/min for those 60 years of age or older .  Average maximal heart rates in each age group exceeded the age-predicted rate ( 220 beats/min age in years ) , which indicates that the exercise test can be considered maximal performance . We defined level of fitness by  total time on the treadmill  at the baseline examination , as in our previous studies ( 20 , 21 ) . Treadmill times were placed in frequency distributions for specific age groups ( 30 to 39 , 40 to 49 , 50 to 59 , or 60 or more years of age ) . The least fit 20 % of the participants in each age group were classified as low fitness , the next 40 % as moderate fitness , and the remaining 40 % as high fitness . The respective cut-points for  total treadmill time  in the low- , moderate- , and high-fitness groups were 945 seconds or less , 946 to 1259 seconds , and 1260 seconds or more for patients 30 to 39 years of age ; 849 seconds or less , 850 to 1020 seconds , and 1021 seconds or more for patients 40 to 49 years of age ; 750 seconds or less , 751 to 1035 seconds , and 1036 seconds or more for patients 50 to 59 years of age ; and 644 seconds or less , 645 to 953 seconds , and 954 seconds or more for patients 60 years of age or older . These cut-points at the 20th and 60th percentiles to define fitness levels were used in previous studies ( 20 , 21 ) and were selected before analysis for our investigation . However , we calculated these cut-points with patients in the current study , from which unhealthy persons were excluded . Therefore , they differ somewhat from the cut-points derived from the entire cohort of the Aerobics Center Longitudinal Study ( 21 ) . For some analyses , such as the models that included change in fitness from baseline to follow-up , cardiorespiratory fitness was expressed as maximal metabolic units ( metabolic equivalents [ METs ] , calculated as the working metabolic rate/resting metabolic rate ; 1 MET is equivalent to an oxygen uptake of 3.5 mL1 kg1 ) achieved on the exercise test . In other analyses , time on the treadmill was used as a continuous variable . Serum sample s were analyzed by using automated techniques in a laboratory that participates in the Centers for Disease Control and Prevention Lipid St and ardization Program . Blood pressure was measured by using auscultatory methods with a mercury sphygmomanometer . We defined high blood pressure as systolic blood pressure of at least 140 mm Hg , diastolic blood pressure of at least 90 mm Hg , or a history of hypertension . Height and weight were measured with a st and ard physician 's scale and stadiometer , and body mass index was calculated as weight in kg/height in m2 . Waist circumference was measured with a st and ard anthropometric tape . Statistical Analysis We used SAS statistical software for data analyses ( 24 ) . The incidence of impaired fasting glucose was calculated for men with normal fasting glucose at baseline , and the incidence of diabetes was based on data from all 8633 patients . For analyses with impaired fasting glucose as the outcome , we excluded 1122 men who had impaired fasting glucose at baseline and an additional 69 men who had normal fasting plasma glucose at baseline but developed diabetes during follow-up . Rates of impaired fasting glucose or diabetes were calculated by dividing the number of incident cases during the study period by the number of person-years over the same period . We defined the study period as the interval between the baseline examination and the last follow-up visit . We used logistic regression to estimate the association between dependent variables and independent variables after adjustment for possible confounding factors . We used general linear models to study the cross-sectional association of fitness level and parental history of diabetes ( 24 , 25 ) . To account for the possible cohort effect of baseline year , we examined the relation between incident cases and baseline year and found no association . We used tests for ordinal linear trend to evaluate the possible relation of higher treadmill time with risk for impaired fasting glucose or diabetes after dividing the sample into the three fitness groups . All P values are two-sided , and those less than 0.05 were considered statistically significant . Role of the Funding Source The funding agencies did not participate in the collection , analysis , or interpretation of data presented in this report or in the decision to su bmi t the manuscript for publication . Results During an average follow-up of 6.1 4.8 years ( range , 1 to 24.8 years ) that included 52 588 person-years , 593 men developed impaired fasting glucose and 149 developed diabetes . Of the men with incident diabetes , 139 ( 93 % ) were not aware of Abstract The purpose of this study was to investigate by direct measurement the cross-sectional relationship between accelerometer-measured physical activity and peak oxygen uptake ( [Vdot]O2peak : ml · min−1 · kg−1 ) , in a population -based cohort of young children , since such data are scarce . The study included 468 children ( 246 boys , 222 girls ) aged 6.7 ± 0.4 years , recruited from a population -based cohort . Peak oxygen uptake was measured by indirect calorimetry during a maximal treadmill exercise test . Physical activity was assessed by accelerometers over a 4-day period . Minutes of sedentary , light , moderate , moderate-to-vigorous , and vigorous activity per day were calculated . Mean counts per minute were considered to reflect total physical activity . Pearson correlation coefficients indicated a weak relationship between daily physical activity variables and [Vdot]O2peak in boys ( r = 0.15–0.28 , P < 0.05 ) , with the exception of time in sedentary and light activity , which was not related to [Vdot]O2peak . None of the daily physical activity variables were related to [Vdot]O2peak in girls , with the exception of a very weak relationship for moderate activity ( r = 0.14 , P < 0.05 ) . Multiple regression analyses indicated that the various physical activity variables explained between 2 and 8 % of the variance in [Vdot]O2peak in boys . In this population -based cohort , most daily activity variables were positively related to aerobic fitness in boys , whereas less clear relationships were observed in girls . Our finding  that physical activity was only uniformly related to aerobic fitness in boys partly contradicts previous studies in older children and adolescents
target: VPA was more strongly associated with reduced body fat and central adiposity compared with MPA and /or MVPA .
  Additionally , VPA was more strongly associated with increased CRF when compared with lower intensities .
  Findings were inconclusive between all PA intensity levels and CM biomarkers , and several significant relationships observed for VPA were attenuated when controlling for CRF .
  A potential VPA dose is identified as yielding favorable health benefits in adiposity and fitness .
  While CM biomarkers were not consistently associated with PA intensity level , the literature suggests VPA may yield health benefits above those received from MPA for reduced adiposity and improved CRF .
background: Background .
  Increasing evidence suggests that vigorous physical activity ( VPA ) in youth may yield greater health benefits than moderate ( MPA ) or moderate-to-vigorous physical activity ( MVPA ) .
  The purpose of this review was to assess the relationship between PA intensity and body composition , cardiorespiratory fitness ( CRF ) , and cardiometabolic ( CM ) biomarkers in youth .