Isometric Exercise Stress Research Articles

Response of Hypertensive Adolescents to Dynamic and Isometric Exercise Stress

Isometric handgrip and dynamic exercise stress tests were performed on 109 hypertensive and 74 normotensive subjects 14 to 17 years old. The hypertensive subjects had resting systolic or diastolic pressures persistently above the 95th percentile on four consecutive examinations. Blood pressures and ECGs were recorded during isometric handgrip (25% maximum effort for four minutes) and bicycle ergometry until the subject was exhausted. The hypertensive subjects increased systolic pressure by an average 16 mm Hg with isometric exercise and 53 mm Hg with dynamic exercise. Control subjects had similar pressure changes, averaging 18 and 54 mm Hg, respectively. During isometric handgrip stress, diastolic pressures increased 12 mm Hg in hypertensive subjects and 18 mm Hg in control subjects. Only two hypertensive adolescents developed systolic pressures exceeding 200 mm Hg during dynamic exercise stress, and none developed systolic pressures above 200 mm Hg during isometric exercise stress. None of the normotensive or hypertensive subjects developed cardiac arrhythmias and the prevalence of ST segment depression during maximal stress was less than 2% in both groups. Therefore, in adolescents with mild to moderate hypertension the risk of developing significant ECG or hemodynamic abnormalities during mild isometric or heavy dynamic exercise is small. We believe the decision to restrict physical activity of an adolescent with elevated pressures should be based on the development of abnormal ST segment depression, cardiac arrhythmias, or excessive blood pressures at the time of exercise stress testing.

Hypertension and Sports

The article "Response of Hypertensive Adolescents to Dynamic and Isometric Exercise Stress" which appears in this issue of Pediatrics (p 579) raises a number of interesting and practical questions for pediatricians. For example, What is hypertension? What does hypertension mean to the child or youth? Should the youth with hypertension be allowed to participate in competitive athletics? What is the role of exercise testing in the evaluation of hypertension? What additional information does it provide? WHAT IS HYPERTENSION? Blood pressure (BP) is the resultant of cardiac output (CO), and systemic vascular resistance (SVR). Because CO and SVR vary from one person to another, it is not surprising that there is a wide range of normal BP values.