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 (> or =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 > 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.

Relative associations of fitness and fatness to fibrinogen, white blood cell count, uric acid and metabolic syndrome.

OBJECTIVE: To examine the relation between fitness and fibrinogen, white blood cell count, uric acid and metabolic syndrome across levels of adiposity in apparently healthy, nonsmoking men. DESIGN: Cross-sectional study of 4057 men from the Aerobics Center Longitudinal Study examining the age-adjusted resting levels and risk of having a clinically significant elevation of fibrinogen, white blood cell count, uric acid and metabolic syndrome score across nine fitness-body fatness combinations. Fitness categories (low fitness, moderately fit or high fitness) were based on a maximal treadmill test. Body mass index (BMI) <25.0 was classified as normal weight, BMI > or = 25.0 but <30.0 as overweight and BMI > or = 30.0 as obese. RESULTS: Fitness (inversely) and BMI (directly) were independently related to the age-adjusted values of all four variables (P for trend P<0.0001 for each). For all four variables, the greatest age-adjusted risk of having a clinically relevant value was found in the low fitness-obese category and the lowest age-adjusted risk was found in the high fitness-normal weight group. CONCLUSION: Fibrinogen, white blood cells, uric acid and metabolic syndrome score are independently related to both fitness (inversely) and fatness (directly). Within levels of fatness, risk for significant elevations in fibrinogen, white blood cells, uric acid and metabolic syndrome score is lower for the higher fitness groups.

Evaluating the reproducibility and validity of the Aerobic Adaptation Test.

PURPOSE: To examine the reproducibility and validity of a new submaximal, ramped cycle ergometer testing methodology known as the Aerobic Adaptation Test (AAT), which attempts to detect changes in submaximal work capacity and minimize participant discomfort. METHODS: 36 sedentary men (mean age = 48.1 +/- 10.2 yr [SD]) and 22 sedentary women (mean age = 51.9 +/- 10.2 yr [SD]) participated in the study. To test reproducibility, participants were tested twice with an average of 20 d between tests (+/-15 d). To test validity, participants were tested before and after a 6-month physical activity intervention, and outcomes were compared with standard measures of fitness (exercise time and oxygen consumption at 70% max heart rate). The main outcome variable of the AAT was work output (W) over a period of 3 min after reaching 70% maximal heart rate. RESULTS: The average work output at 70% HRmax was highly reproducible, with a test-retest reliability of rho = 0.85 (P < 0.001). Average work output at 70% HRmax significantly increased after 6 months of physical activity intervention (87.8 +/- 32.9 W vs 95.5 +/- 37.9 W, P = 0.002), and changes in average work output at 70% HRmax correlated with changes in exercise time to elicit 70% HRmax (r = 0.87, P < 0.001) as well as changes in VO2 at 70% HRmax (r = 0.75, P < 0.001). Thus, the AAT appears to be a valid measure of submaximal work capacity. CONCLUSIONS: The AAT is a reproducible and valid measure of submaximal work capacity that can serve as an effective means to evaluate physical activity interventions.

Usefulness of cardiorespiratory fitness as a predictor of all-cause and cardiovascular disease mortality in men with systemic hypertension.

There is an inverse gradient of mortality across levels of cardiorespiratory fitness in healthy adults; however, the association of fitness to mortality in persons with comorbidities such as hypertension is not fully understood. This study quantifies the relation of cardiorespiratory fitness to all-cause mortality and cardiovascular disease (CVD) mortality in hypertensive men. In this observational cohort study, we calculated death rates for low, moderate, and high fitness categories in normotensive (n = 15,726) and hypertensive (n = 3,184) men, and in men without a history of hypertension but with elevated blood pressure (BP) (systolic BP > or = 140 or diastolic BP > or = 90 mm Hg) at baseline (n = 3,257). The participants were 22,167 men (average age 42.6 +/- 9.2 years [mean +/- SD]) who underwent a medical examination that included a maximal exercise test during 1970 to 1993, with mortality follow-up to December 31, 1994. We identified 628 deaths (188 from CVD) during 224,173 man-years of observation. There was an inverse linear trend across fitness groups for all-cause and CVD mortality. The relative risk (95% confidence interval [CI]), using the low fitness group as reference, for all-cause mortality in hypertensive men was 0.45 (95% CI 0.31 to 0.65) and 0.42 (95% CI 0.27 to 0.66) for moderate and high fitness groups, respectively, and in men with elevated BP, 0.49 (95% CI 0.34 to 0.70) and 0.44 (95% CI 0.29 to 0.68) for moderate and high fitness groups, respectively. The pattern of results was similar for CVD mortality. There was an inverse linear relation between fitness and death rate for all-cause mortality in both the uncontrolled and controlled hypertensive groups. This study provides evidence that moderate to high levels of cardiorespiratory fitness provide protection against all-cause and CVD mortality in hypertensive men and men without a history of hypertension but with elevated BP at examination.

Comparison of a dietary record using reported portion size versus standard portion size for assessing nutrient intake.

OBJECTIVE: Because the percentage of missing portion sizes was large in the Aerobics Center Longitudinal Study (ACLS), careful consideration of the accuracy of standard portion sizes was necessary. The purpose of the present study was to investigate the consequences of using standard portion sizes instead of reported portion sizes on subjects' nutrient intake. METHODS: In 2307 men and 411 women, nutrient intake calculated from a 3-day dietary record using reported portion sizes was compared with nutrient intake calculated from the same record in which standard portion sizes were substituted for reported portion sizes. RESULTS: The standard portion sizes provided significantly lower estimates (>/= 20%) of energy and nutrient intakes than the reported portion sizes. Spearman correlation coefficients obtained by the two methods were high, ranging from 0.67 to 0.93. Furthermore, the agreement between both methods was fairly good. Thus, in the ACLS the use of standard portion sizes rather than reported portion sizes did not appear to be suitable to assess the absolute intake at the group level, but appeared to lead to a good ranking of individuals according to nutrient intake. These results were confirmed by the Continuing Survey of Food Intake by Individuals (CSFII), in which the assessment of the portion size was optimal. When the standard portion sizes were adjusted using the correction factor, the ability of the standard portion sizes to assess the absolute nutrient intake at the group level was considerably improved. CONCLUSIONS: This study suggests that the adjusted standard portion sizes may be able to replace missing portion sizes in the ACLS database.

Alcohol intake and incidence of type 2 diabetes in men.

OBJECTIVE: To evaluate the relation between alcohol intake and incidence of type 2 diabetes. RESEARCH DESIGN AND METHODS: This prospective study included 8,663 men with fasting plasma glucose measurements from at least two medical examinations. Alcohol intake was classified into five groups: nondrinkers and four quartiles (Qs) of drinkers according to the amount of alcohol intake. Type 2 diabetes was diagnosed by 1997 American Diabetes Association criteria. RESULTS: There were 149 incident cases of type 2 diabetes during 52,588 person-years of follow-up. There was a U-shaped association between alcohol intake and diabetes, with the lowest incidence of diabetes at Q2 (61.9-122.7 g/week). As compared with Q2, men in Q3 and Q4 had a 2.2- (95% CI 1.2-3.9, P = 0.01) and 2.4-fold (1.4-4.4, P<0.01) risk of developing diabetes, while nondrinkers and men in Q1 had 1.8- (1.0-3.3, P<0.05) and 1.4-fold (0.7-2.6, P = 0.34) higher risk of diabetes, respectively. These associations persisted after adjustment for age, fasting plasma glucose, smoking, BMI, blood pressure, serum triglyceride concentration, cardiorespiratory fitness, HDL cholesterol, waist circumference, and parental diabetes. CONCLUSIONS: We observed an elevated risk of developing type 2 diabetes in nondrinkers and men with high alcohol intakes, when compared with men who reported moderate alcohol intake. Men with a high alcohol intake may be able to reduce their risk of developing type 2 diabetes if they drink less.

Low fasting plasma glucose level as a predictor of cardiovascular disease and all-cause mortality.

BACKGROUND: Although medical textbooks usually classify fasting plasma glucose <70 or 80 mg/dL (<3.89 or 4.44 mmol/L) as abnormal, the prognosis for patients with low fasting plasma glucose is unclear. METHODS AND RESULTS: We conducted prospective cohort studies among 40 069 men and women to investigate the association between fasting plasma glucose levels and cardiovascular disease and all-cause mortality. We documented a U-shaped relation between fasting plasma glucose and mortality. In addition to diabetes and impaired fasting glucose levels, low fasting plasma glucose levels were also associated with high mortality. After multivariate adjustment for age, sex, study population, ethnicity, current smoking status, high blood pressure, total cholesterol, body mass index, triglycerides, history of cardiovascular disease and cancer, and a family history of cardiovascular disease, patients with fasting plasma glucose <70 mg/dL (<3.89 mmol/L) had a 3.3-fold increased risk of cardiovascular disease mortality, and patients with fasting plasma glucose 70 to 79 mg/dL (3.89 to 4.43 mmol/L) had a 2.4-fold increased risk compared with the risk in patients with fasting plasma glucose 80 to 109 mg/dL (4.44 to 6.05 mmol/L) (tests for trend P<0.0001). Participants with low fasting plasma glucose levels also had increased risk of all-cause mortality (test for trend P<0.0001). CONCLUSIONS: Participants with low fasting plasma glucose levels had a high risk of cardiovascular disease and all-cause mortality.

Low cardiorespiratory fitness and physical inactivity as predictors of mortality in men with type 2 diabetes.

BACKGROUND: Although physical activity is recommended as a basic treatment for patients with diabetes, its long-term association with mortality in these patients is unknown. OBJECTIVE: To evaluate the association of low cardiorespiratory fitness and physical inactivity with mortality in men with type 2 diabetes. DESIGN: Prospective cohort study. SETTING: Preventive medicine clinic. PATIENTS: 1263 men (50+/-10 years of age) with type 2 diabetes who received a thorough medical examination between 1970 and 1993 and were followed for mortality up to 31 December 1994. MEASUREMENTS: Cardiorespiratory fitness measured by a maximal exercise test, self-reported physical inactivity at baseline, and subsequent death determined by using the National Death Index. RESULTS: During an average follow-up of 12 years, 180 patients died. After adjustment for age, baseline cardiovascular disease, fasting plasma glucose level, high cholesterol level, overweight, current smoking, high blood pressure, and parental history of cardiovascular disease, men in the low-fitness group had an adjusted risk for all-cause mortality of 2.1 (95% CI, 1.5 to 2.9) compared with fit men. Men who reported being physically inactive had an adjusted risk for mortality that was 1.7-fold (CI, 1.2-fold to 2.3-fold) higher than that in men who reported being physically active. CONCLUSIONS: Low cardiorespiratory fitness and physical inactivity are independent predictors of all-cause mortality in men with type 2 diabetes. Physicians should encourage patients with type 2 diabetes to participate in regular physical activity and improve cardiorespiratory fitness.

Relationship between low cardiorespiratory fitness and mortality in normal-weight, overweight, and obese men.

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: Prospective 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.

The association between cardiorespiratory fitness and impaired fasting glucose and type 2 diabetes mellitus in men.

BACKGROUND: Several studies show an inverse association between self-reported physical activity and type 2 diabetes. It is not known whether physical activity or cardiorespiratory fitness is associated with the onset of objectively determined impaired fasting glucose and type 2 diabetes. OBJECTIVE: To determine whether cardiorespiratory fitness, an objective marker of physical activity, is associated with risk for impaired fasting glucose and type 2 diabetes. DESIGN: Population-based prospective study. SETTING: Preventive medicine clinic. PATIENTS: 8633 nondiabetic men (of whom 7511 did not have impaired fasting glucose) who were examined at least twice. MEASUREMENTS: Cardiorespiratory fitness (determined by a maximal exercise test on a treadmill), fasting plasma glucose level, and other clinical and personal characteristics and incidence of impaired fasting glucose and type 2 diabetes. RESULTS: During an average follow-up of 6 years, 149 patients developed type 2 diabetes and 593 patients developed impaired fasting glucose. After age, cigarette smoking, alcohol consumption, and parental diabetes were considered, men in the low-fitness group (the least fit 20% of the cohort) at baseline had a 1.9-fold risk (95% CI, 1.5- to 2.4-fold) for impaired fasting glucose and a 3.7-fold risk (CI, 2.4- to 5.8-fold) for diabetes compared with those in the high-fitness group (the most fit 40% of the cohort). The risk for impaired fasting glucose was elevated in older men and those with a higher body mass index. Age, body mass index, blood pressure, triglyceride level, and a history of parental diabetes were also directly related to risk for type 2 diabetes. CONCLUSIONS: Low cardiorespiratory fitness was associated with increased risk for impaired fasting glucose and type 2 diabetes. A sedentary lifestyle may contribute to the progression from normal fasting glucose to impaired fasting glucose and diabetes. Risk for type 2 diabetes was elevated in older persons and those with higher body mass index, blood pressure, and triglyceride levels and a parental history of diabetes.

Physical fitness and clustering of risk factors associated with the metabolic syndrome.

PURPOSE: The purposes of this study were to 1) assess the prevalence of clustering of metabolic markers of the MS in a defined population and 2) determine the association between CRF and such clustering in a large group of adult men (N = 15,537) and women (N = 3,899). METHODS: Metabolic markers of the MS included systolic blood pressure (BP) > or = 140 mm Hg, serum triglycerides > or = 150 mg x dL(-1), fasting blood glucose > or = 110 mg x dL(-1), and elevated central adiposity (waist circumference > 100 cm). Cardiorespiratory fitness was defined as total time on a maximal treadmill exercise test. The cohort was grouped by the number of metabolic abnormalities and level of CRF. Associations between CRF and the number of metabolic abnormalities were assessed using proportional odds logit models. RESULTS: Among men, the age-adjusted cumulative odds ratio for abnormal markers of the MS was 3.0 (95% C.I. 2.7-3.4; P < 0.001) for the least-fit men when compared with moderately-fit ones, and 10.1 (95% C.I. 9.1-11.2; P < 0.001) when compared with the most-fit men. Among women, the age-adjusted cumulative odds ratio was 2.7 (95% C.I. 2.1-3.5; P < 0.001) for the least-fit women when compared with moderately-fit ones, and 4.9 (95% C.I. 3.8-6.3; P < 0.001) when compared with the most-fit women. CONCLUSIONS: These cross-sectional results suggest that low CRF is associated with an increased clustering of the metabolic abnormalities associated with the MS in both adult men and women and support the need for future prospective analyses.

Comparison of lifestyle and structured interventions to increase physical activity and cardiorespiratory fitness: a randomized trial.

CONTEXT: Even though the strong association between physical inactivity and ill health is well documented, 60% of the population is inadequately active or completely inactive. Traditional methods of prescribing exercise have not proven effective for increasing and maintaining a program of regular physical activity. OBJECTIVE: To compare the 24-month intervention effects of a lifestyle physical activity program with traditional structured exercise on improving physical activity, cardiorespiratory fitness, and cardiovascular disease risk factors. DESIGN: Randomized clinical trial conducted from August 1, 1993, through July 31, 1997. PARTICIPANTS: Sedentary men (n = 116) and women (n = 119) with self-reported physical activity of less than 36 and 34 kcal/kg per day, respectively. INTERVENTIONS: Six months of intensive and 18 months of maintenance intervention on either a lifestyle physical activity or a traditional structured exercise program. MAIN OUTCOME MEASURES: Primary outcomes were physical activity assessed by the 7-Day Physical Activity Recall and peak oxygen consumption (VO2peak) by a maximal exercise treadmill test. Secondary outcomes were plasma lipid and lipoprotein cholesterol concentrations, blood pressure, and body composition. All measures were obtained at baseline and at 6 and 24 months. RESULTS: Both the lifestyle and structured activity groups had significant and comparable improvements in physical activity and cardiorespiratory fitness from baseline to 24 months. Adjusted mean changes (95% confidence intervals [CIs]) were 0.84 (95% CI, 0.42-1.25 kcal/kg per day; P<.001) and 0.69 (95% CI, 0.25-1.12 kcal/kg day; P = .002) for activity, and 0.77 (95% CI, 0.18-1.36 mL/kg per minute; P = .01) and 1.34 (95% CI, 0.72-1.96 mL/kg per minute; P<.001) for VO2peak for the lifestyle and structured activity groups, respectively. There were significant and comparable reductions in systolic blood pressure (-3.63 [95% CI, -5.54 to -1.72 mm Hg; P<.001] and -3.26 [95% CI, -5.26 to -1.25 mm Hg; P = .002]) and diastolic blood pressure (-5.38 [95% CI, -6.90 to -3.86 mm Hg; P<.001] and -5.14 [95% CI, -6.73 to -3.54 mm Hg; P<.001) for the lifestyle and structured activity groups, respectively. Neither group significantly changed their weight (-0.05 [95% CI, -1.05 to 0.96 kg; P = .93] and 0.69 [95% CI, -0.37 to 1.74 kg; P = .20]), but each group significantly reduced their percentage of body fat (-2.39% [95% CI, -2.92% to -1.85%; P<.001] and -1.85% [95% CI, -2.41 % to -1.28%; P<.001]) in the lifestyle and structured activity groups, respectively. CONCLUSIONS: In previously sedentary healthy adults, a lifestyle physical activity intervention is as effective as a structured exercise program in improving physical activity, cardiorespiratory fitness, and blood pressure.

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.

Influences of cardiorespiratory fitness levels and other predictors on cardiovascular disease mortality in men.

PURPOSE: This investigation quantifies the relation between cardiorespiratory fitness levels and cardiovascular disease (CVD) mortality within strata of other CVD predictors. METHODS: Participants included 25,341 male Cooper Clinic patients who underwent a maximal graded exercise test. CVD death rates were determined for low (least fit one-fifth), moderate (next two-fifths), and high (top two-fifths) cardiorespiratory fitness categories by strata of smoking habit, blood cholesterol level, resting blood pressure, and health status. There were 226 cardiovascular deaths during 211,996 man-years of follow-up. RESULTS: For individuals with none of the major CVD predictors (smoking, elevated resting systolic blood pressure, elevated blood cholesterol), there was a strong inverse relation (P = 0.001) between fitness level and CVD mortality. An inverse relation between CVD mortality and fitness level was seen within strata of cholesterol levels and health status. No evidence of a trend (P = 0.60) for decreased mortality was seen across fitness levels for individuals with elevated systolic blood pressure; however, a strong inverse gradient (P < 0.001) was seen across fitness levels for individuals with normal systolic blood pressure. There was a tendency for association between high levels of fitness and decreased CVD mortality in smokers compared with low and moderately fit smokers (P < 0.076). There was no significant association between level of fitness and CVD mortality for individuals with multiple (two or more) predictors (P = 0.325). Approximately 20% of the 226 CVD deaths in the population studied were attributed to low fitness level. CONCLUSIONS: Moderate and high levels of cardiorespiratory fitness seem to provide some protection from CVD mortality, even in the presence of well established CVD predictors.

Reduction in cardiovascular disease risk factors: 6-month results from Project Active.

BACKGROUND: Project Active is a randomized clinical trial that compares a lifestyle physical activity intervention with a traditional structured exercise intervention. The purpose of this paper is to report 6-month results of these interventions on cardiovascular disease (CVD) risk factors among healthy, sedentary, middle-aged men and women, and to examine the psychological strategies used in each group (Lifestyle and Structured) to reach the level of physical activity recommended by the Centers for Disease Control and Prevention (CDC) and American College of Sports Medicine (ACSM) and to achieve changes in these CVD risk factors. METHODS: A total of 116 initially sedentary men (mean +/- SD self-reported physical activity, 33.2 +/- 1.4 kcal.kg-1.day-1) and 119 women (32.9 +/- 1.0 kcal.kg-1.day-1), ages 35-60 years (46.0 +/- 6.7 years) were randomly assigned to a 6-month lifestyle physical activity counseling intervention or a 6-month gymnasium-based structured program. At baseline and 6 months, changes in lipid and lipoprotein-cholesterol concentrations, blood pressure, and body composition and cognitive and behavioral measures of change were assessed. One-way analyses of variance with covariate adjustment were used to test for between-group differences in CVD risk factors. Associations between achieving the CDC/ACSM criterion and changes in cognitive and behavioral measures were assessed with multiple logistic regression models. RESULTS: After 6 months of intervention, 78% of Lifestyle participants and 85% of Structured participants were meeting or exceeding the CDC/ACSM recommendation of accumulating 30 min or more of moderate-intensity physical activity on most, preferably all, days of the week. This was verified by a significant increase in cardiorespiratory fitness in both groups. The adjusted mean increase in maximal METs (VO2peak divided by 3.5 ml.kg-1.min-1) between treadmill tests was 0.4 kcal.kg-1.hr-1 (P < 0.001) for Lifestyle and 1.1 kcal.kg-1.hr-1 (P < 0.001) for Structured. There was a significant difference between intervention groups for this outcome. Both groups had significant reductions in total cholesterol, total cholesterol/HDL-C ratio, diastolic blood pressure, and percentage of body fat. There were no significant between-group differences in changes in these outcomes. Adjusted mean changes in total cholesterol, systolic blood pressure, and percentage of body fat in Lifestyle [in Structured] participants were -0.2 [-0.3] mmol.L-1, -3.2[-1.8] mm Hg, and -1.4 [-1.7] %, respectively. There were significant associations between achieving the CDC/ACSM physical activity criterion and greater use of the cognitive and behavioral strategies of change. Both groups changed self-efficacy and many of the behavioral measures, but there were no significant differences between intervention groups. CONCLUSIONS: These results demonstrate that lifestyle physical activity counseling is as effective as structured exercise programs in increasing physical activity and improving CVD risk factors after 6 months among initially sedentary men and women. Furthermore, specific cognitive and behavioral counseling strategies were increased significantly as a result of the intervention. These strategies are effective and could be used in a wide variety of settings.

Physical activity and health of college men: longitudinal observations.

The College Alumni Health Study has examined host and environmental characteristics in youth and adult life as they relate to subsequent development of specific chronic diseases. Campus archives have provided physical, psychological, and social data on some 57,500 men and women who were born between 1896 and 1934, and who entered Harvard College or the University of Pennsylvania between 1916 and 1950, generally at age 17-20 years. These college data have been studied subsequently to assess whether characteristics in youth predisposed students to chronic diseases (nonfatal and fatal) later in life. Follow-up questionnaires, mailed to alumni, generally aged 35-85 years, in the 1960s, 1970s, 1980s, and 1990s have provided mid-life information on the health status and health habits of survivors, and official death certificates have provided data on decedents. This information has been studied, in fashion similar to the college data, for personal characteristics and ways of living that influenced health and longevity of these middle-aged and elderly men. Longitudinal observations continue today, in search of causes of specific chronic diseases.

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.

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.