Xuemei Sui

Mounting evidence has firmly established that low levels of cardiorespiratory fitness (CRF) are associated with a high risk of cardiovascular disease, all-cause mortality, and mortality rates attributable to various cancers. A growing body of epidemiological and clinical evidence demonstrates not only that CRF is a potentially stronger predictor of mortality than established risk factors such as smoking, hypertension, high cholesterol, and type 2 diabetes mellitus, but that the addition of CRF to traditional risk factors significantly improves the reclassification of risk for adverse outcomes. The purpose of this statement is to review current knowledge related to the association between CRF and health outcomes, increase awareness of the added value of CRF to improve risk prediction, and suggest future directions in research. Although the statement is not intended to be a comprehensive review, critical references that address important advances in the field are highlighted. The underlying premise of this statement is that the addition of CRF for risk classification presents health professionals with unique opportunities to improve patient management and to encourage lifestyle-based strategies designed to reduce cardiovascular risk. These opportunities must be realized to optimize the prevention and treatment of cardiovascular disease and hence meet the American Heart Association's 2020 goals.

OBJECTIVE: To examine prospectively the association between muscular strength and mortality from all causes, cardiovascular disease, and cancer in men. DESIGN: Prospective cohort study. SETTING: Aerobics centre longitudinal study. PARTICIPANTS: 8762 men aged 20-80. MAIN OUTCOME MEASURES: All cause mortality up to 31 December 2003; muscular strength, quantified by combining one repetition maximal measures for leg and bench presses and further categorised as age specific thirds of the combined strength variable; and cardiorespiratory fitness assessed by a maximal exercise test on a treadmill. RESULTS: During an average follow-up of 18.9 years, 503 deaths occurred (145 cardiovascular disease, 199 cancer). Age adjusted death rates per 10,000 person years across incremental thirds of muscular strength were 38.9, 25.9, and 26.6 for all causes; 12.1, 7.6, and 6.6 for cardiovascular disease; and 6.1, 4.9, and 4.2 for cancer (all P<0.01 for linear trend). After adjusting for age, physical activity, smoking, alcohol intake, body mass index, baseline medical conditions, and family history of cardiovascular disease, hazard ratios across incremental thirds of muscular strength for all cause mortality were 1.0 (referent), 0.72 (95% confidence interval 0.58 to 0.90), and 0.77 (0.62 to 0.96); for death from cardiovascular disease were 1.0 (referent), 0.74 (0.50 to 1.10), and 0.71 (0.47 to 1.07); and for death from cancer were 1.0 (referent), 0.72 (0.51 to 1.00), and 0.68 (0.48 to 0.97). The pattern of the association between muscular strength and death from all causes and cancer persisted after further adjustment for cardiorespiratory fitness; however, the association between muscular strength and death from cardiovascular disease was attenuated after further adjustment for cardiorespiratory fitness. CONCLUSION: Muscular strength is inversely and independently associated with death from all causes and cancer in men, even after adjusting for cardiorespiratory fitness and other potential confounders.

Substantial evidence has established the value of high levels of physical activity, exercise training (ET), and overall cardiorespiratory fitness in the prevention and treatment of cardiovascular diseases. This article reviews some basics of exercise physiology and the acute and chronic responses of ET, as well as the effect of physical activity and cardiorespiratory fitness on cardiovascular diseases. This review also surveys data from epidemiological and ET studies in the primary and secondary prevention of cardiovascular diseases, particularly coronary heart disease and heart failure. These data strongly support the routine prescription of ET to all patients and referrals for patients with cardiovascular diseases, especially coronary heart disease and heart failure, to specific cardiac rehabilitation and ET programs.

CONTEXT: Although levels of physical activity and aerobic capacity decline with age and the prevalence of obesity tends to increase with age, the independent and joint associations among fitness, adiposity, and mortality in older adults have not been adequately examined. OBJECTIVE: To determine the association among cardiorespiratory fitness ("fitness"), adiposity, and mortality in older adults. DESIGN, SETTING, AND PATIENTS: Cohort of 2603 adults aged 60 years or older (mean age, 64.4 [SD, 4.8] years; 19.8% women) enrolled in the Aerobics Center Longitudinal Study who completed a baseline health examination during 1979-2001. Fitness was assessed by a maximal exercise test, and adiposity was assessed by body mass index (BMI), waist circumference, and percent body fat. Low fitness was defined as the lowest fifth of the sex-specific distribution of maximal treadmill exercise test duration. The distributions of BMI, waist circumference, and percent body fat were grouped for analysis according to clinical guidelines. MAIN OUTCOME MEASURE: All-cause mortality through December 31, 2003. RESULTS: There were 450 deaths during a mean follow-up of 12 years and 31 236 person-years of exposure. Death rates per 1000 person-years, adjusted for age, sex, and examination year were 13.9, 13.3, 18.3, and 31.8 across BMI groups of 18.5-24.9, 25.0-29.9, 30.0-34.9, and > or =35.0, respectively (P = .01 for trend); 13.3 and 18.2 for normal and high waist circumference (> or =88 cm in women; > or =102 cm in men) (P = .004); 13.7 and 14.6 for normal and high percent body fat (> or =30% in women; > or =25% in men) (P = .51); and 32.6, 16.6, 12.8, 12.3, and 8.1 across incremental fifths of fitness (P < .001 for trend). The association between waist circumference and mortality persisted after further adjustment for smoking, baseline health status, and BMI (P = .02) but not after additional adjustment for fitness (P = .86). Fitness predicted mortality risk after further adjustment for smoking, baseline health, and either BMI, waist circumference, or percent body fat (P < .001 for trend). CONCLUSIONS: In this study population, fitness was a significant mortality predictor in older adults, independent of overall or abdominal adiposity. Clinicians should consider the importance of preserving functional capacity by recommending regular physical activity for older individuals, normal-weight and overweight alike.