OBJECTIVE To evaluate heart rate variability during an inspiratory muscle endurance protocol at three different load levels [30%, 60% and 80% of maximal inspiratory pressure], in patients who had previously undergone coronary artery bypass grafting. METHODS Nineteen late postoperative myocardial revascularization patients participating in a cardiovascular rehabilitation program were studied. ...

The aim of the following study is to analyze the mechanical efficiency on heart rate frequency and oxygen consumption during exercise bicycle test. The following study included seven respondents (men) aged 19-28 years, all students in the National Sports Academy “Vassil Levski” (Sofia, Bulgaria) – specialists in cycling. During two consecutive days, they were administered to sub maximal bicycle...

Despite the growing popularity of energy drinks, many do not realize the negative effects on the cardiovascular system. The purpose of this study was to examine the effects of energy drink ingestion on estimated VO2max, heart rate (HR), systolic and diastolic BP (SBP and DBP, respectively), rate pressure product (RPP), and RPE at rest and during exercise. Seven healthy adults (age: 24.3 ± 3.5 y...

BACKGROUND Sudden cardiac death is the leading cause of on-duty death in United States firefighters. Accurately assessing cardiopulmonary capacity is critical to preventing, or reducing, cardiovascular events in this population. METHODS A total of 83 male firefighters performed Wellness-Fitness Initiative (WFI) maximal exercise treadmill tests and direct peak VO2 assessments to volitional fat...

BACKGROUND The relative contributions of decreases in maximal heart rate, stroke volume, and oxygen extraction and of changes in body weight and composition to the age-related decline in maximal oxygen uptake (VO2max) are unclear and may be influenced by sex and level of physical activity. METHODS AND RESULTS To investigate mechanisms by which aging, sex, and physical activity influence VO2ma...