Slide 15 Important StudiesPhysical activity and coronary heart diseaseLongshoreman study (Paffenbarger & Hale 1975)Mortality from CHD in San Francisco dockworkersLeisure time physical activity and CVDSlide 7Slide 8Additional pointsAerobic fitness and CVDAerobics Center Longitudinal Study (ACLS) Blair et al., 1996Aerobic fitness vs. CVD riskSlide 13Slide 14Quintiles of fitness (treadmill time) and mortality riskSlide 16Slide 17Physical activity and CVD riskSlide 19Slide 20Cardiovascular Disease (CVD) & Physical ActivityUnit 2 Lecture 45 Important Studies–Morris Bus Driver–Paffenbarger Longshoremen–Paffenbarger Harvard Alumni–Morris Civil Servants–Bair Aerobics Longitudinal StudyPhysical ActivityPhysical FitnessPhysical activity and coronary heart disease•Physical inactivity is recognized by American Heart Association and World Health Organization as major INDEPENDENT risk factor for coronary heart disease•First studies used occupational physical activity–Morris bus driver/conductor studies–11/14 days 50 weeks/yr–Conductors had 50% fewer heart attacks and sudden death from coronary heart diseaseLongshoreman study(Paffenbarger & Hale 1975)•In San Francisco (n = 6300, 35-74yr)•Light, moderate or heavy occupational physical activity •Followed for 22 yrs–75yo, or death•Outcome: - deaths from Coronary heart deseaseMortality from CHD in San Francisco dockworkersLeisure time physical activity and CVD•Harvard alumni study (Paffenbarger, et al. 1978)•1916 – 1950 graduates sent questionnaire in 1962 or 1966•Outcome: risk of heart attack•Exposures: 1) Current physical activity (in 1962 or 1966)2) sports activity while studentRates of first heart attack in Harvard Alumni, according to current physical activity and participation as studentCHD rates per 1000 man yr of observation in civil servants: effect of exercise holds across confounding factorsSource: Morris et al. (1990).Note: Groups indicate frequency of vigorous exercise: 1, highest, 4 lowestAdditional points1) No study has found a higher risk of heart disease among active people compared with lower-active people.2) Benefits in women, older men and in different minority groups3) Relative risk of physical inactivity = 1.9–similar to cholesterol, hypertension, smokingAerobic fitness and CVD•Examine the relationship with fitness and not physical activity–More precise measure–Less risk of misclassification–Will not miss true relationship•Most findings are from the Aerobics Center Longitudinal Study (ACLS)–Aerobic fitness measured in more than 25,000 menAerobics Center Longitudinal Study (ACLS)Blair et al., 1996•25,000 males, 7080 women•Time to exhaustion on treadmill test = aerobic fitness•8 year follow-up•3 fitness categories–lowest (20%) fitness–moderate (40%) fitness- highest (40%) fitnessAerobic fitness vs. CVD risk•ACLS: Relative risk for CVD related death is 1.7 for men in lowest fitness group vs. all other higher fitness groups–Smoking: 1.6–High blood pressure (>140mmHg): 1.3–High cholesterol: 1.6–Family history: 1.2•Moderate fitness appears to protect against other risk for CVD mortalityHow do we interpret this?Is there a critical VO2 max threshold or level of activity offering protection?•Level of fitness below which there is a marked increase in risk for CHD?–Males: 8-9 METs (28-32 ml/kg/min)–Females: 6-7 METs (21-25ml/kg/min)What are some activities in these MET ranges?Quintiles of fitness (treadmill time) and mortality riskFitness groupMen WomenRelative risk1 (low) 3.44 4.652 1.37 2.423 1.46 1.434 1.17 0.765 (high) 1.00 1.00Lowest fitness groups had highest risk of deathtrend remained when age, smoking, cholesterol, glucose and parental CHD were accounted forBlair et al., JAMA, 1989,Source: Tanasescu, et al Health Professionals Follow-up Study (2002).More vigorous activity confers greater benefitOutcome: CHD riskMETSMET Hr/wkHr/wkHr/wkMET Hr/wkmiles/hrPhysical activity and CVD riskReview of evidence for Guidelines for all AmericansHarvard School of Public Health (I. Min Lee 2010)A review of 20 prospective cohort studies (1995-2007) found that compared to the least active subjects, the most active subjects had a 30-35% reduction of risk in developing CVDThe SAME reduction in CVD risk with exercise is found in older individuals! (based on studies on 60-80-year olds)Similar reduction in women as in men!Physical activity and CVD riskDo combined healthy lifestyle behaviors make a difference in CVD risk?•HALE (Knoops, et al, 2004)1. Mediterranean diet2. Physical activity3. non-smoking4. moderate alcohol Each lifestyle factor hadan independent associationwith mortalityRelative risk for CHD in women, according to number of low-risk factors exhibitedNurses’ Health Study1) healthy diet2) non-smoking3) exercise4) BMI<25kg/m25) moderate alcohol consumption14 year