Short-term isometric exercise reduces systolic blood pressure in hypertensive adults: possible role of reactive oxygen species.

OBJECTIVE: A short-term isometric exercise protocol was tested in ten hypertensive individuals to determine its efficacy as a high blood pressure-reducing intervention.
DESIGN: The study was a prospective case study of 10 hypertensive individuals (8 men, 2 woman, mean age = 52 + 5 years) who underwent six weeks of isometric exercise training (three sessions/week).
METHODS: Blood pressure, blood lipids and markers of oxidative stress were monitored before, during and following the isometric intervention. Electron spin resonance spectroscopy was used to directly measure radicals in the blood samples.
RESULTS: After six weeks, systolic blood pressure decreased an average 13 mm Hg (p < 0.05) from a mean blood pressure of 146 to 133 mm Hg, a level that is below the usual 140 mm Hg hypertension threshold. Blood lipids were unchanged, but markers of oxidative stress were affected, with a dramatic decrease in exercise-induced oxygen centered radicals (-266%), (p < 0.05) and an increased resting whole blood glutathione:oxidized glutathione (+61%) in hypertensive adults following six weeks of isometric exercise.
CONCLUSION: Six weeks of isometric exercise training was effective in lowering systolic but not diastolic blood pressure in pre-hypertensive and hypertensive individuals, and enhanced antioxidant protection is a likely underlying mechanism.