Factors influencing isometric exercise training‐induced reductions in resting blood pressure

Abstract

Hypertension is a major health concern, and current recommendations for blood pressure management (lifestyle modifications and pharmacological intervention) have not been universally successful. For two decades, isometric exercise training (IET) has become established as effective at reducing in resting BP (RBP) in a short period (4-10 weeks). The most common IET modes have comprised isometric handgrip (IHG) or isometric bilateral leg (IBL) training and 4 × 2-min contractions at ∼20-50% maximal voluntary contraction with 1-5-min rest between. Although this type of exercise training could have important implications, for hypertensive patients and in preventing hypertension development, little is known about the mechanisms responsible for IET-induced RBP reductions. This uncertainty derives from a lack of understanding concerning the most effective IET programs for specific populations. Possible influential factors and mechanisms include age, sex, pre-existing disease and medication, and IET-induced adaptations in the exercising muscle and nervous system, which are discussed in this review. Designing effective IET programs may involve manipulation of exercise intensity, frequency, duration and mode, as well as consideration of yet discovered mechanisms for RBP reductions. We call for additional research designed to understand more about the mechanisms involved in IET-induced RBP reductions for maximum effectiveness.

Effects of isometric resistance training on blood pressure and physical fitness of men

“…One type of exercise, which has gained support in health studies in the recent decades, is resistance training (RT), which is based on efforts made against a specific resistance and aims to increase power, strength and/or muscle endurance over time 2,9 . In addition, some studies have shown significant reductions in resting blood pressure (BP) after dynamic and isometric RT, and have suggested that four weeks of RT may contribute to the treatment and / or prevention of SAH 11,12,13 . Suggesting that isometric RT may have a potential for the largest reductions in BP 13,14 .…”

“…Its use has been supported by different meta-analyses 11,13 , and was recently included in important scientific statements as a promising useful tool in the management of BP. In which mechanisms that result in possible decreases in BP after intervention include neural (sympatho-vagal activity), vascular (endothelial function) and inflammatory adaptations 12,14 .…”

“…However, the majority of studies have employed isometric handgrip exercise 14 , and it is still unclear if other forms of isometric exercise also improve BP. Recent studies suggest that isometric exercises including larger muscle mass could potentiate BP decreases 15 and also improve health-related physical fitness, including strength 9 and aerobic fitness 2,3,16 .…”

“…Recent studies suggest that isometric exercises including larger muscle mass could potentiate BP decreases 15 and also improve health-related physical fitness, including strength 9 and aerobic fitness 2,3,16 . Very few trials using isometric RT with a duration of over 10 weeks are reported 12,14 , so the responses of BP beyond this period are still unknown, especially when compared to dynamic RT. Thus, this emphasizes the need for further studies.…”

“…Most studies with isometric RT that showed reductions in BP have involved small muscle groups 14 . However, recent strategies have begun to use large muscle groups both acutely 17,18 and chronically 15 , but they do not report gains in physical fitness.…”