James B. Kampert

The Association of Changes in Physical-Activity Level and Other Lifestyle Characteristics with Mortality among Men

BACKGROUND Recent trends toward increasing physical exercise, stopping cigarette smoking, and avoiding obesity may increase longevity. We analyzed changes in the lifestyles of Harvard College alumni and the associations of these changes with mortality. METHODS Men who were 45 to 84 years of age in 1977 and who had reported no life-threatening disease on questionnaires completed in 1962 or 1966 and again in 1977 were classified according to changes in lifestyle characteristics between the first and second questionnaires. We analyzed changes in their level of physical activity, cigarette smoking, blood pressure, and body weight, and the relation of these factors to mortality between 1977 and 1985. RESULTS Of the 10,269 men, 476 died during this period (which totaled 90,650 man-years of observation). Beginning moderately vigorous sports activity (at an intensity of 4.5 or more metabolic equivalents) was associated with a 23 percent lower risk of death (95 percent confidence interval, 4 to 42 percent; P = 0.015) than not taking up moderately vigorous sports. Quitting cigarette smoking was associated with a 41 percent lower risk (95 percent confidence interval, 20 to 57 percent; P = 0.001) than continuing smoking, but with a 23 percent higher risk than constant nonsmoking. Men with recently diagnosed hypertension had a lower risk of death than those with long-term hypertension (relative risk, 0.75; 95 percent confidence interval, 0.55 to 1.02; P = 0.057), as did men with consistently normal blood pressure (relative risk, 0.52; 95 percent confidence interval, 0.40 to 0.68; P < 0.001). Maintenance of lean body mass was associated with a lower mortality rate than long-term, recent, or previous obesity. The associations between changes in lifestyle and mortality were independent and were largely undiminished by age. Our findings on death from coronary heart disease mirrored those on death from all causes. CONCLUSIONS Beginning moderately vigorous sports activity, quitting cigarette smoking, maintaining normal blood pressure, and avoiding obesity were separately associated with lower rates of death from all causes and from coronary heart disease among middle-aged and older men.

Influences of cardiorespiratory fitness and other precursors on cardiovascular disease and all-cause mortality in men and women

OBJECTIVE To quantify the relation of cardiorespiratory fitness to cardiovascular disease (CVD) mortality and to all-cause mortality within strata of other personal characteristics that predispose to early mortality. DESIGN--Observational cohort study. We calculated CVD and all-cause death rates for low (least fit 20%), moderate (next 40%), and high (most fit 40%) fitness categories by strata of smoking habit, cholesterol level, blood pressure, and health status. SETTING Preventive medicine clinic. STUDY PARTICIPANTS Participants were 25341 men and 7080 women who completed preventive medical examinations, including a maximal exercise test. MAIN OUTCOME MEASURES Cardiovascular disease and all-cause mortality. RESULTS There were 601 deaths during 211996 man-years of follow-up, and 89 deaths during 52982 woman-years of follow-up. Independent predictors of mortality among men, with adjusted relative risks (RRs) and 95% confidence intervals (CIs), were low fitness (RR, 1.52;95% CI, 1.28-1.82), smoking (RR, 1.65; 95% CI, 1.39-1.97), abnormal electrocardiogram (RR, 1.64;95% CI, 1.34-2.01), chronic illness (RR, 1.63;95% CI, 1.37-1.95), increased cholesterol level (RR, 1.34; 95% CI, 1.13-1.59), and elevated systolic blood pressure (RR, 1.34; 95% CI, 1.13-1.59). The only statistically significant independent predictors of mortality in women were low fitness (RR, 2.10; 95% Cl, 1.36-3.21) and smoking (RR, 1.99; 95% Cl, 1.25-3.17). Inverse gradients were seen for mortality across fitness categories within strata of other mortality predictors for both sexes. Fit persons with any combination of smoking, elevated blood pressure, or elevated cholesterol level had lower adjusted death rates than low-fit persons with none of these characteristics. CONCLUSIONS Low fitness is an important precursor of mortality. The protective effect of fitness held for smokers and nonsmokers, those with and without elevated cholesterol levels or elevated blood pressure, and unhealthy and healthy persons. Moderate fitness seems to protect against the influence of these other predictors on mortality. Physicians should encourage sedentary patients to become physically active and thereby reduce the risk of premature mortality.

Low Cardiorespiratory Fitness and Physical Inactivity as Predictors of Mortality in Men with Type 2 Diabetes

Exercise has become a standard therapy for patients with type 2 diabetes (1). Regular exercise improves conventional clinical risk factors, cardiorespiratory fitness, and components of the insulin resistance syndrome (2-6). However, it is unclear whether physical activity improves the prognosis of patients with diabetes. No data are available on the association of physical activity or cardiorespiratory fitness with mortality in patients with diabetes. The overall benefit of exercise for these patients is unclear, and some experts are concerned that macrovascular and microvascular complications may be worsened by an exercise program (1, 7). Some consider exercise only as a supplement to diet therapy (8). Studies have shown repeatedly that low cardiorespiratory fitness and physical inactivity are directly associated with cardiovascular disease and all-cause mortality (9-14), and our preliminary study with a small number of end points suggested that this association might persist across plasma glucose levels (15). In the current study, we evaluated the prospective association of cardiorespiratory fitness and physical inactivity with mortality in men who have type 2 diabetes. Methods The material presented in this report was derived from the Aerobics Center Longitudinal Study (ACLS), a prospective observational study of patients examined at The Cooper Clinic in Dallas, Texas. The study was reviewed and approved annually by the institutional review board at The Cooper Institute. Additional details of study methods and study group characteristics of this cohort have been published elsewhere (12, 13). Patients Participants were men with type 2 diabetes who completed a baseline medical evaluation at The Cooper Clinic in Dallas, Texas, during 1970 to 1993. These men came to The Cooper Clinic for a medical examination and health counseling. Many were sent by their employers for these services, some were referred by their personal physicians, and others were self-referred. More than 92% of the patients are white, and most are employed in executive or professional occupations; more than 75% are college graduates. Study participants come from middle and upper socioeconomic strata, but they are similar to other well-characterized study group-based cohorts in terms of blood pressure, cholesterol level, body weight, and cardiorespiratory fitness (6, 16, 17). We excluded men taking insulin and those with a history of cancer at baseline. Clinical Examination The baseline evaluation was performed after participants gave informed written consent for the baseline medical examination and registration in the follow-up study. Examinations followed an overnight fast of at least 12 hours and included personal and family health histories, a questionnaire on demographic characteristics and health habits, a physical examination, a maximal exercise test on a treadmill, anthropometry, electrocardiography, blood chemistry analyses, and blood pressure measurement. Technicians who followed a standard manual of operations administered all procedures. Questionnaire Patients completed an extensive self-report of personal and family medical diseases and conditions. Each clinic physician examines only four or five patients per day and thus has time for thorough additional probing of items on the self-reported questionnaire. This complete review of the patients medical history and the subsequent physical examination are strengths of the ACLS and provide a more thorough evaluation of baseline health status than is possible in many epidemiologic studies. The questionnaire also featured items on health habits, including current smoking status and smoking history and whether the participant was currently dieting to lose weight or following any other special dietary plan. Physical activity pattern was ascertained by self-report on the questionnaire. An extensive list of leisure-time physical activities was presented, and participants indicated activities in which they had participated in the 3 months before the examination. In later study years, they gave additional details on the number of times per week and the duration of exercise sessions. Laboratory Evaluations Cardiorespiratory fitness was assessed by using a maximal exercise test that followed a modified version of Balke and Wares protocol (18). Briefly, the test began with the participant walking on a horizontal treadmill at 88 m/min. After the first minute, the elevation increased to 2%, and it further 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 increased to 5.4 m/min until the participant reached volitional fatigue. Exercise test performance with this protocol correlates highly with measured maximal oxygen uptake (r=0.92) (19). Serum samples were analyzed by using automated techniques in a laboratory that participates in and meets the quality control standards of the Centers for Disease Control and Prevention Lipid Standardization Program. Blood pressure was measured by auscultatory methods with a mercury sphygmomanometer according to American Heart Association guidelines (20). The lowest of three blood pressure measurements at the clinic examination was recorded as the baseline blood pressure. Height and weight were measured by using a standard beam-balance scale and stadiometer, and body mass index was calculated. Type 2 Diabetes Diabetes was defined according to criteria of the American Diabetes Association: fasting plasma glucose level of 7.0 mmol/L or greater ( 126 mg/dL) (21). Three hundred seventy patients who did not meet this criterion but who gave a history of physician-diagnosed diabetes were considered to have diabetes. Patients were classified as having known diabetes or unknown diabetes according to their diabetes status before the baseline Cooper Clinic examination. Definition of Exposure Variables The principal exposure variables used in our analyses were cardiorespiratory fitness and self-reported physical activity. These exposures were determined at the baseline examination. Cardiorespiratory Fitness We categorized total time from the maximal exercise test into frequency distributions for specific age groups (30 to 39, 40 to 49, 50 to 59, and 60 years). The least fit 20% of the participants in each age group were classified as low fit, the next 40% of the distribution as moderately fit, and the highest 40% as high fit. We have used these cut-points to define fitness in previous studies (12, 13), and they are based on our entire cohort rather than on diabetic patients only. We selected these cut-points before undertaking the current analysis. Cardiorespiratory fitness is expressed as maximal metabolic units (METs) attained during the exercise test. The METs are calculated as the working metabolic rate divided by the resting metabolic rate, and 1 MET is equivalent to an oxygen uptake of 3.5 mL1 kg 1. Physical Activity Patients who reported walking, jogging, or participating in aerobic exercise programs in the 3 months before the examination were classified as active, regardless of the frequency and duration of exercise. Otherwise, patients were classified as inactive. In our cohort, more than 76% of men who reported being active at baseline still reported being active at the second visit after more than 1 year. In comparison, only 34% of men who reported being inactive at baseline reported being active at the second examination (P<0.001). Self-reported physical activity status in our cohort is correlated with maximal exercise test performance (6, 22). Baseline or Parental Cardiovascular Disease We defined baseline cardiovascular disease as a personal history of heart attack, stroke, or a revascularization procedure; an abnormal resting or exercise electrocardiogram; or the highest heart rate during exercise testing that was less than 85% of the age-predicted maximal heart rate ([220 age in years] 0.85). Men who reported a history of cardiovascular disease in either parent were classified as having parental cardiovascular disease. Conventional Cardiovascular Disease Risk Factors We assigned men to risk strata for conventional cardiovascular disease risk factors on the basis of recent recommendations (23). We defined high blood pressure as systolic blood pressure of 140 mm Hg or more, diastolic blood pressure of 90 mm Hg or more, or a history of physician-diagnosed hypertension. We classified participants with a total cholesterol level of 6.2 mmol/L (240 mg/dL) or more as having high cholesterol, those with self-reported current smoking as current smokers, those with a self-reported parental history of myocardial infarction or stroke as having a history of parental cardiovascular disease, those with a body mass index less than 25.0 kg/m2 as normal weight, and those with a body mass index of 25.0 kg/m2 or more as overweight. Statistical Analysis Our primary outcome measure was all-cause mortality. We used the National Death Index to identify decedents in the ACLS. The National Death Index has been shown to be an effective, accurate means of ascertaining deaths in the general population, with a sensitivity of about 96% and a specificity of 100% (24). We obtained official death certificates from states in which there were ACLS decedents, and we had the certificates coded by a nosologist according to the International Classification of Diseases, Ninth Revision. Only the underlying cause of death was used in analyses for this report. Data were analyzed by using the SAS statistical package (SAS Institute, Inc., Cary, North Carolina). The analyses assumed that physical activity and fitness were essentially unchanged during the study period. We used survival curves to estimate survival function against time and log [log (survival time)] to check the proportional hazards model assumption. Log [log (survival function)] estimates were approximately parallel across exposure g

The Association between Cardiorespiratory Fitness and Impaired Fasting Glucose and Type 2 Diabetes Mellitus in Men

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 prospective 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 prospective study of the association between physical activity and impaired fasting glucose has been published. We examined the relation of cardiorespiratory fitness, objectively 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 Associations current guidelines (1). Methods Patients In our population-based prospective 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 reviewed 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 subclinical 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 questionnaire 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 standard 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 samples were analyzed by using automated techniques in a laboratory that participates in the Centers for Disease Control and Prevention Lipid Standardization 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 standard physicians scale and stadiometer, and body mass index was calculated as weight in kg/height in m2. Waist circumference was measured with a standard 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 submit 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 their

Cardiorespiratory Fitness Is Inversely Associated With the Incidence of Metabolic Syndrome A Prospective Study of Men and Women

Background—Few studies have reported the relationship between cardiorespiratory fitness and metabolic syndrome incidence, particularly in women. Methods and Results—We prospectively studied 9007 men (mean±SD age, 44±9 years; body mass index, 25±3 kg/m2) and 1491 women (age, 44±9 years; body mass index, 22±2 kg/m2) who were free of metabolic syndrome and for whom measures of waist girth, resting blood pressure, fasting lipids, and glucose were taken during baseline and follow-up examinations. Baseline cardiorespiratory fitness was quantified as duration of a maximal treadmill test. Metabolic syndrome was defined with NCEP ATP-III criteria. During a mean follow-up of 5.7 years, 1346 men and 56 women developed metabolic syndrome. Age-adjusted incidence rates were significantly lower (linear trend, P<0.001) across incremental thirds of fitness in men and women. After further adjustment for potential confounders, multivariable hazard ratios for incident metabolic syndrome among men in the low, middle, and upper thirds of fitness, were 1.0 (referent), 0.74 (95% CI, 0.65 to 0.84), and 0.47 (95% CI, 0.40 to 0.54) (linear trend P<0.001); in women, they were 1.0 (referent), 0.80 (95% CI, 0.44 to 1.46), and 0.37 (95% CI, 0.18 to 0.80) (linear trend P=0.01), respectively. Similar patterns of significant inverse associations between fitness and metabolic syndrome incidence were seen when men were stratified on categories of body mass index, age, and number of baseline metabolic risk factors, but patterns were variable in women. Conclusions—Low cardiorespiratory fitness is a strong and independent predictor of incident metabolic syndrome in women and men. Clinicians should consider the potential benefits of greater cardiorespiratory fitness in the primary prevention of metabolic syndrome, particularly among patients who have already begun to cluster metabolic syndrome components.

Associations Between Cardiorespiratory Fitness and C-Reactive Protein in Men

Objective—This study examined the association between cardiorespiratory fitness and C-reactive protein (CRP), with adjustment for weight and within weight categories. Methods and Results—We calculated median and adjusted geometric mean CRP levels, percentages of individuals with an elevated CRP (≥2.00 mg/L), and odds ratios of elevated CRP across 5 levels of cardiorespiratory fitness for 722 men. CRP values were adjusted for age, body mass index, vitamin use, statin medication use, aspirin use, the presence of inflammatory disease, cardiovascular disease, and diabetes, and smoking habit. We found an inverse association of CRP across fitness levels (P for trend<0.001), with the highest adjusted CRP value in the lowest fitness quintile (1.64 [1.27 to 2.11] mg/L) and the lowest adjusted CRP value in the highest fitness quintile (0.70 [0.60 to 0.80] mg/L). Similar results were found for the prevalence of elevated CRP across fitness quintiles. We used logistic regression to model the adjusted odds for elevated CRP and found that compared with the referent first quintile, the second (odds ratio [OR] 0.43, 95% CI 0.22 to 0.85), third (OR 0.33, 95% CI 0.17 to 0.65), fourth (OR 0.23, 95% CI 0.12 to 0.47), and fifth (OR 0.17, 95% CI 0.08 to 0.37) quintiles of fitness had significantly lower odds of elevated CRP. Similar results were found when examining the CRP-fitness relation within categories of body fatness (normal weight, overweight, and obese) and waist girth (<102 or ≥102 cm). Conclusions—Cardiorespiratory fitness levels were inversely associated with CRP values and the prevalence of elevated CRP values in this sample of men from the Aerobics Center Longitudinal Study.

Associations of muscle strength and fitness with metabolic syndrome in men

PURPOSE To examine the associations for muscular strength and cardiorespiratory fitness with the prevalence of metabolic syndrome among men. METHODS Participants were 8570 men (20-75 yr) for whom an age-specific muscular strength score was computed by combining the body weight adjusted one-repetition maximum measures for the leg press and the bench press. Cardiorespiratory fitness was quantified by age-specific maximal treadmill exercise test time. RESULTS Separate age and smoking adjusted logistic regression models revealed a graded inverse association for metabolic syndrome prevalence with muscular strength (beta = -0.37, P < 0.0001) and cardiorespiratory fitness (beta = -1.2, P < 0.0001). The association between strength and metabolic syndrome was attenuated (beta = -0.08, P < 0.01) when further adjusted for cardiorespiratory fitness. The association between cardiorespiratory fitness and metabolic syndrome was unchanged (beta = -1.2, P < 0.0001) after adjusting for strength. Muscular strength added to the protective effect of fitness among men with low (P trend = 0.0002) and moderate (P trend < 0.0001) fitness levels. Among normal weight (BMI < 25), overweight (BMI 25-30), and obese (BMI >or= 30) men, respectively, being strong and fit was associated with lower odds (73%, 69%, and 62% respectively, P < 0.0001) of having prevalent metabolic syndrome. CONCLUSIONS Muscular strength and cardiorespiratory fitness have independent and joint inverse associations with metabolic syndrome prevalence.

Physical activity, physical fitness, and all-cause and cancer mortality: A prospective study of men and women

We studied physical fitness and physical activity in relation to all-cause and cancer mortality in a cohort of 7080 women and 25,341 men examined at the Cooper Clinic in Dallas, Texas, during 1970 to 1989. Physical fitness was assessed at baseline by a maximal treadmill exercise test, while physical activity was self-reported on the attendant health habits questionnaire. Both men and women averaged about 43 years of age at baseline (range, 20 to 88 years), and they were followed for approximately 8 years on average. Through the end of 1989, the women contributed 52,982 person-years of observation and incurred 89 deaths, including 44 deaths due to cancer. The men contributed 211,996 person-years and incurred 601 deaths, with 179 due to cancer. After adjustment for baseline differences in age, examination year, cigarette habit, chronic illnesses, and electrocardiogram abnormalities, we found a strong inverse association between risk of all-cause mortality and level of physical fitness in both men and women (P for trend < 0.001). Physically active men also were at lower risk of all-cause mortality than were sedentary ones (P for trend = 0.01). Among women, however, self-reported physical activity was not significantly related to risk of death from all causes. The risk of mortality from cancer declined sharply across increasing levels of fitness among men (P for trend < 0.001), whereas among women the gradient was suggestive but not significant (P for trend = 0.07). Physically active men also were at lower risk of death from cancer than were sedentary men (P for trend = 0.002), but among women physical activity was unrelated to cancer mortality.

Changes in physical activity and other lifeway patterns influencing longevity.

We studied the adoption or maintenance of physical activity and other optional lifeway patterns for their influence on mortality rates of Harvard College alumni. Men aged 45-84 in 1977, surveyed by questionnaire in 1962 or 1966 and again in 1977, were followed from 1977 through 1988 or to age 90. Of 14,786 alumni, 2,343 died in 165,402 man-years of follow-up. Relative risks of death, standardized for potential confounding influences, for men who between questionnaires increased their physical activity through walking, stair climbing, and sports or recreational activities to 1,500 kcal or more per wk were 0.72 (95% confidence interval 0.64-0.82), compared with 1.00 for men who remained less active. Corresponding relative risks for men who adopted moderately vigorous sports play (> or = 4.5 METs) were 0.73 (0.65-0.81) vs 1.00 for men not adopting such sports; and for cigarette smokers who quit, 0.74 (0.65-0.84) vs 1.00 for persistent smokers. Men with recently diagnosed hypertension had a lower death risk than long-term hypertensives (0.80; 0.70-0.92), as did men with consistent normotension (0.52; 0.47-0.58). Changes in body-mass index had little influence on mortality during follow-up. These findings fit the hypothesis that adopting a physically active lifeway, quitting cigarette smoking, and remaining normotensive independently delay all-cause mortality and extend longevity.

Six-month physical activity and fitness changes in Project Active, a randomized trial

PURPOSE Project Active is a randomized clinical trial (N = 235) comparing a lifestyle physical activity program with a structured exercise program in changing physical activity (total energy expenditure [kcal.kg-1.d-1]) and cardiorespiratory fitness (VO2peak in mL.kg-1.min-1). METHODS Sedentary but healthy adults (N = 235) aged 35-60 years received 6 months of intensive intervention. RESULTS Analysis of covariance (ANCOVA), adjusting for baseline measure, age, gender, body mass index (BMI), cohort, and ethnicity, showed that at 6 months both lifestyle and structured groups significantly increased energy expenditure over baseline (P < 0.001). The mean increases +/- SE, 1.53 +/- 0.19 kcal.kg-1.d-1 for the lifestyle group and 1.34 +/- 0.20 kcal.kg-1 d-1 for the structured group, were not significantly different between groups (P = 0.49). For cardiorespiratory fitness, both groups had significant increases from baseline (P < 0.001). Mean increases +/- SE were 1.58 +/- 0.33 mL.kg-1.min-1 and 3.64 +/- 0.33 mL.kg-1.min-1 for the lifestyle and structured groups, respectively. This was significantly greater in the structured group (P < 0.001). We also studied changes in intensity of physical activity. Both groups significantly increased moderate intensity activity from baseline, but the increase was significantly greater in the lifestyle group than the structured group (P = 0.02). In contrast, the structured group increased its hard activity more than the lifestyle group, but the difference was not significantly different (P = 0.02). In contrast, the structured group increased its hard increased (P < 0.01) for both groups by 0.25 kcal.kg-1.d-1. CONCLUSION Both intervention approaches are effective for increasing physical activity and fitness over a 6-month period in initially sedentary men and women.