Yiling J. Cheng

Effects of physical activity on exercise tests and respiratory function

Background: Exercise is an important component of pulmonary rehabilitation for patients with chronic lung disease. Objective: To explore the role of physical activity in maintaining cardiac and respiratory function in healthy people. Methods: Cardiorespiratory fitness was measured by a maximal treadmill test (MTT), and respiratory function was tested by spirometry. The cross sectional study included data from 24 536 healthy persons who were examined at the Cooper Clinic between 1971 and 1995; the longitudinal study included data from 5707 healthy persons who had an initial visit between 1971 and 1995 and a subsequent visit during the next five years. All participants were aged 25–55 years and completed a cardiorespiratory test and a medical questionnaire. Results: In the cross sectional study, after controlling for covariates, being active and not being a recent smoker were associated with better cardiorespiratory fitness and respiratory function in both men and women. In the follow up study, persons who remained or became active had better MTT than persons who remained or became sedentary. Men who remained active had higher forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) than the other groups. Smoking was related to lower cardiorespiratory fitness and respiratory function. Conclusions: Physical activity and non-smoking or smoking cessation is associated with maintenance of cardiorespiratory fitness. Change in physical activity habits is associated with change in cardiorespiratory fitness, but respiratory function contributed little to this association during a five year follow up.

Does physical activity reduce the risk of developing peptic ulcers

Background—Although Helicobacter pylori has been identified as a major cause of chronic gastritis, not all infected patients develop ulcers, suggesting that other factors such as lifestyle may be critical to the development of ulcer disease. Aim—To investigate the role physical activity may play in the incidence of peptic ulcer disease. Methods—The subjects were men (8529) and women (2884) who attended the Cooper Clinic in Dallas between 1970 and 1990. The presence of gastric or duodenal ulcer disease diagnosed by a doctor was determined from a mail survey in 1990. Subjects were classified into three physical activity groups according to information provided at the baseline clinic visit (before 1990): active, those who walked or ran 10 miles or more a week; moderately active, those who walked or ran less than 10 miles a week or did another regular activity; the referent group consisting of those who reported no regular physical activity. Results—With the use of gender specific proportional hazards regression models that could be adjusted for age, smoking, alcohol use, body mass index, and self reported tension, active men were found to have a significant reduction in risk for duodenal ulcers (relative hazard (95% confidence interval) for the active group was 0.38 (0.15 to 0.94) and 0.54 (0.30 to 0.96) for the moderately active group). No association was found between physical activity and gastric ulcers for men or for either type of ulcer for women. Conclusions—Physical activity may provide a non-pharmacological method of reducing the incidence of duodenal ulcers among men.

Cardiorespiratory fitness, adiposity, and incident asthma in adults

Our data support that excess fat increases the risk of incident asthma among adults, and this risk might be attenuated by higher fitness. Physical fitness enhancement in overfat people may reduce risk of incident asthma.

Heart rate recovery after treadmill exercise testing is an independent predictor of stroke incidence in men with metabolic syndrome

SUMMARY BACKGROUND AND AIMS Heart rate recovery (HRR), a measure of the heart rate which decreases after a graded exercise test, has been associated with mortality and cardiovascular diseases. However, the association between HRR and risk of stroke has not been fully determined in men with metabolic syndrome (MetS). METHODS Participants were 3886 men with MetS, aged 40-79 years, who completed a maximal exercise test during 1979-2004. We calculated 5-min HRR as the primary predictor and identified HRR tertiles; tertile 1 (<59 bpm), tertile 2 (59-71 bpm), and tertile 3 (>71 bpm). Stroke incidence was ascertained from responses to mail-back surveys during 1982-2004. Differences in baseline characteristics across HRR tertiles were examined using general linear model. Hazard ratios (HRs) and 95% confidence intervals (95% CIs), were estimated using Cox regression model after adjusted for potential confounders. RESULTS We identified 90 incident stroke cases during an average follow-up of 15.2 years. After adjusting for age-, examination year-, and survey response indicator, a significant inverse association between HRR and incident stroke was observed in men with MetS (p < 0.001). Compared with the lowest tertile of HRR, adjusted HRs in the second and third tertiles were 0.96 (0.53-1.74) and 0.41 (0.20-0.87), respectively. We also found a significant linear trend (p < 0.03) across increments of HRR. CONCLUSION Delayed HRR was independently associated the higher risk of incident stroke in men with MetS. This suggests that HRR have prognostic value of stroke risk for men with MetS.