Hours Of Physical Activity Research Articles

EFFECT OF CHANGES IN PHYSICAL ACTIVITY ON MARKERS OF BLOOD COAGULATION AND FIBRINOLYSIS

1135 We examined the effects of changes in physical activity (PA) on markers of blood coagulation and fibrinolysis in 108 adults in the Seasonal Variation of Cholesterol Study [56% men, age=49±12.5 yrs, BMI=27.3±4.6 kg·m−2 (mean±SD)]. Fasting morning blood samples and PA measures were collected at baseline and then every 3 months for 1 year. Three 24-hour PA recalls were obtained at each assessment point to estimate total (TA), household (HA), occupational (OA), and leisure-time activity (LA) in MET-hrs·d−1. Baseline values of fibrinogen (FIBR), factor VIIc activity (FVIIc), and unbound plasminogen activator inhibitor-1 (PAI-1) were (mean ±SD); 306±83 mg·dl−1, 107±22%, and 55±43 ng·ml−1, respectively. Random effects models quantifying the slope (b) of the relationship between change in PA and change in FIBR, PAI-1, and FVIIc revealed that subjects reporting increases in TA had reductions in FIBR [b(men)=−0.65, (−1.7, 0.4); b(women)=−2.51, (−4.4, −0.6); (b, (95%CI)]. Increased LA was also associated with favorable reductions of FIBR in both men [b= −1.97, (−4.8, 0.4)] and women [b=−1.84, (−5.0, 1.3)]. In women only, increased OA and HA were associated with reduced FIBR levels [b=−2.05, (−5.8, 1.7) and b=−3.05, (−5.6, −0.5), respectively]. No associations were observed between any PA measure and PAI-1 or FVIIc. In conclusion, increased PA at home, at work, and during leisure-time may lower risk of cardiovascular events by favorably reducing basal levels of FIBR. Support: ACSM Fellowship for Epidemiological Research and NIH ROI HL-52745.

EVALUATION OF THE HEALTH PLAN ACTIVITY SURVEY 199

Valid and reliable surveys are needed to measure physical activity (PA) in women. The Health Plan Activity Survey (HPAS) was adapted from the Baecke survey to measure PA in women. The purpose of this study was to evaluate the validity and reliability of the HPAS against direct and indirect measures of PA. The HPAS has five indices - childcare, housework, occupation, sports,& active living habits. A total score is computed by summing the indices and dividing by 5. Subjects were 50 women from 20-60 years old ([horizontal bar over]x ± SD, 39.2 ± 12.0 years). Most were white, college educated, and employed. Only 6 had children < 12 years old. Subjects completed the HPAS twice, one month apart. PA validation measures were: 14 days of 24-hour PA records & Caltrac data, VO2 max, and% Fat. Data were analyzed by regressing the PA validation scores on the HPAS index scores. Test-retest reliability for all indices was good: r>.70. Age-adjusted correlation coefficients were: Table Data suggest all indices, but occupation, have moderate validity and good reliability. Correlations between the HPAS and PAR might have been larger than observed if they had not had different recall periods (HPAS-past year; PAR-14 days). The low correlation between the active living index and the PAR may be due to error in recalling and classifying these activities. The occupational PA index items need further study.

Ability of the Caltrac accelerometer to assess daily physical activity levels.

The purpose of this study was to determine the ability of the Caltrac accelerometer to assess habitual daily physical activity levels. The ability of the Caltrac accelerometer to assess 24-hour physical activity (PA) levels was studied in 28 men and 50 women, age 20 to 59 years, with varying levels of self-reported PA. Twelve days of Caltrac readings obtained over 1 year's duration were compared to simultaneously recorded 48-hour PA records. Additionally, 28 days of Caltrac readings obtained over 1 year's duration were compared to mean values of the following validation measures assessed repeatedly over a 1-year period: a 4-week version of the Minnesota Leisure Time Physical Activity Questionnaire (FWH); VO2peak; and percent body fat. The Caltrac measurements of movement (in MET minutes per day-1) were significantly associated with the following: PA record indices of total (r = .51) and heavy (r = .34) and PA; FWH indices of total (r = .30), heavy R = .36) and moderate (r = .23) PA;, and VO2peak (r = .24). However, the Caltrac measurements of caloric PA record and FWH indices of PA, although there were directly associated with percent body fat (r = .50) and inversely associated with VO2peak (r = -.26). Caltrac measurements of movement exhibited a moderate associated with several criterion measures related to habitual PA, whereas Caltrac measurements of total energy expenditure, were not reflective of varying levels of PA.

Physical Activity in Older Middle-aged Men and Reduced Risk of Stroke: The Honolulu Heart Program

From 1965 to 1968, the Honolulu Heart Program began following 8,006 men in a prospective study of cardiovascular disease. At the time of study enrollment, an estimate of current 24-hour habitual physical activity was collected from each subject. On the basis of a calculated physical activity index, subjects were classified as being inactive, partially active, or active. This report examines the relation between the levels of physical activity and stroke that occurred among 7,530 of the men over 22 years of follow-up. Risk of stroke was examined separately in younger (45-54 years) middle-aged men and older (55-68 years) middle-aged men. Among the older men, those who were inactive or partially active experienced a three- to fourfold excess incidence of hemorrhagic stroke as compared with active men (p < 0.01). There was a two- to threefold excess of intracerebral hemorrhage in men who were inactive or partially active as compared with those who were active (p < 0.05). An excess of subarachnoid hemorrhage was observed in inactive older men, with only one event occurring in those who were active (p < 0.05). After exclusion of subjects with hypertension, diabetes mellitus, and left ventricular hypertrophy, the relative risk of hemorrhagic stroke for inactive men versus active men was 3.7 (95% confidence interval (CI) 1.3-10.4). In older men who did not smoke cigarettes, the relative risk of thromboembolic stroke among inactive men versus active men was 2.8 (95% CI 1.2-6.7), and when partially active older men were compared with those who were active, the relative risk was 2.4 (95% CI 1.0-5.7). These findings persisted after control for the residual effects of systolic blood pressure and other risk factors for stroke. Benefits of physical activity in reducing the risk of thromboembolic stroke were not observed in men who smoked cigarettes. The authors conclude that physical activity may be important in reducing the risk of stroke, particularly among nonsmoking men in older middle age.

The relation between blood pressure variation and daily physical activity in early morning surge in blood pressure

Morning rise in blood pressure (morning surge; MS) has been shown to be associated with the occurrence of myocardial ischemic events and stroke. This study aimed to elucidate the incidence and the mechanism of MS in hypertensive patients (HT). We monitored ambulatory blood pressure (BP) and physical activity in 68 untreated HTs using TM2421 (A & D Co. Ltd.) and ACTIVETRACER (GMS Ltd.) for detection of MS. MS was defined as a rise in BP > 50 mmHg (90% tile of 35 normotensives) during early morning (4:00 to 9:00 A.M.) compared with the lowest basal BP at night. MS was seen in 41 patients (52.6%) and was classified into two groups; MS1: BP rose steeply after waking up (27 patients) and MS2: BP started to rise gradually during sleep (14 patients). The mean age of MS1 was significantly higher than that of MS2 (72 vs. 62 years, p < 0.01). BP reached its basal value earlier in MS2 than in MS1 at night though the basal BP values were comparable between the two groups. Mean 24-hour BP and physical activity were similar between the two groups, though significantly higher incidence of cases with a correlation between SBP and activity was seen in MS1. In conclusion, there are two types of MS, the mechanisms of which may differ. MS occurring immediately after waking up was more common in older HTs, and possibly was related to augmented arousal response in BP, while MS beginning gradually during sleep was more common in younger HTs and was characterized by reaching basal BP earlier at night.

Physical activity and physical demand on the job and risk of cardiovascular disease and death: The Framingham Study

Cardiovascular events over 24 years of surveillance were examined in 1166 men participating in the Framingham Study, classified by physical demands of their work and by a 24-hour index of physical activity. Findings are based on 303 noncardiovascular, 220 coronary, and 325 cardiovascular deaths in men aged 45 to 64 years at time of physical activity assessment. For level of physical activity over 24 hours, there is a clear trend of improved overall, cardiovascular, and coronary mortality with increased level of physical activity at all ages, including the elderly. The effect is sustained with a more pronounced effect with the passage of time, despite presumed decrease in level of activity. The mortality benefits apply both in those with and without intervening overt cardiovascular disease, making it unlikely that the physical inactivity-mortality relationships reflects already existent myocardial damage. For physical demands of the job, there is only a suggestion (not statistically significant) of benefit for cardiovascular mortality including coronary deaths. In sharp contrast, noncardiovascular mortality was positively related to both physical demand of the job and 24-hour physical activity index.

The role of physical activity in nicotine's effects on body weight

The present study examined the effects of chronic nicotine administration and cessation of nicotine administration on body weight and 24-hour physical activity of rats. There was a significant, inverse, dose-effect relationship between nicotine administration and body weight. Cessation of nicotine was accompanied by increased rates of body weight gain compared to controls. The changes in body weight during nicotine administration could not be explained by changes in physical activity. However, decreases in physical activity after cessation of nicotine appeared to contribute to post-drug body weight increases. These findings have implications for weight control after cessation of cigarette smoking.