Potential hypertensive risk during circuit training in normotensive and first-degree hypertensive subjects

Combined aerobic-anaerobic exercise seems to be a valid, non-pharmacological way to reduce hypertension. Circuit training (CT) is often used to train normotensive (N) and hypertensive (H) subjects, but not all circuits are equal and some exercises could be dangerous for H subjects. The objectives of the study, carried out in accordance with the Basic Principles of the Declaration of Helsinki, were to assess the trend of blood pressure response in N and H subjects during a CT session; define which exercises in CT are most safe for H subjects; and verify the possible risks of a CT session to excessively raise blood pressure in H subjects. Methods: Ten N and 10 H subjects, moderately trained males, were enrolled. Arterial blood pressure was measured at rest and at the end of each exercise. Heart rate (HR) was recorded by a heart rate monitor. Subjects performed at 7 CT stations: bike 65, 70 and 75% of HR_max, leg press, leg extension, leg curl and squat. Results: Mean arterial blood pressure was significantly higher in H than N subjects. Leg curl, leg extension and bike at 65% HR_max were the mostly clinically safe. Bike at 70-75% HR_max, isometric squat and leg press exceeded the safe limit. Conclusions: It is necessary to monitor blood pressure during a CT programme with bike at 70-75% of HR_max, isometric squat and leg press as they were shown to be a potential risk for H subjects.