ABSTRACT
BACKGROUND: In spite of the benefits of physical activity, exercise may provoke acute cardiac events in susceptible individuals. Understanding risk factors of exercise-related acute cardiac events may identify opportunities for prevention. METHODS: A case-control study was conducted to examine determinants of acute cardiac events in athletes. The cases were athletes who suffered an acute cardiac event during or shortly after vigorous exercise. Athletes who visited a hospital because of a minor sports injury were selected as controls. Information on cardiovascular disease, family history of cardiovascular disease, cardiovascular symptoms and other potential risk factors was collected through questionnaires. RESULTS: 57 cases (mean age 41.8 years, range 11-73) and 57 controls (mean age 40.9 years, range 13-68) were included in the study. Athletes with a history of cardiovascular disease were at a markedly increased risk for cardiac events during exercise (OR = 32; 95% CI 7.4 to 143). Smoking (OR 5.9; 95% CI 1.9 to 18), fatigue (OR = 12; 95% CI 1.2 to 118) and flu-like symptoms (OR 13; 95% CI 1.4 to 131) in the month preceding the event were related to acute cardiac events in athletes. CONCLUSIONS: Prior cardiovascular disease, smoking, and a recent episode of fatigue or flu-like symptoms are associated with an increased risk of exercise-related acute cardiac events. Athletes and physicians should pay careful attention when these factors exist or occur.
Subject(s)
Cardiovascular Diseases/complications , Death, Sudden, Cardiac/prevention & control , Exercise , Sports , Adolescent , Adult , Aged , Case-Control Studies , Child , Death, Sudden, Cardiac/etiology , Female , Health Knowledge, Attitudes, Practice , Humans , Male , Middle Aged , Risk Factors , Smoking/adverse effects , Surveys and Questionnaires , Young AdultABSTRACT
The purpose of this study was to examine mechanical efficiency (ME) and physiological responses during asynchronous (the pedal arms oriented in opposing directions) arm-cranking exercise (AACE) and compare these responses to those obtained during synchronous (the pedal arms oriented in the same direction) arm-cranking exercise (SACE). Ten male subjects participated in the study and performed two exercise tests, one AACE and the other SACE in counter-balanced order. Each test consisted of submaximal (30, 60 and 90 W) and maximal exercise. At 30 W, gross ME was significantly lower during SACE compared to AACE, whereas at 60 W and 90 W no differences between the two types of exercise could be observed. We found that at lower power output levels the flywheel mass and its moment of inertia may have induced more body movements for compensation, which may have been more pronounced during SACE than during AACE. At higher levels of power output this flywheel masseffect was less, which explained the lack of differences in ME at these levels. Physiological responses to maximal AACE or SACE exercise were not significantly different. The results indicated that there were no differences in physiological responses to AACE and SACE exercise at higher exercise intensities. However, at lower levels of power output ME seemed to decrease, most likely as a result of the flywheel-mass effect, which was more pronounced during SACE.
