Hypertension is the condition of having chronically elevated blood pressure. The American Heart Association defines hypertension as systolic pressure above 140 and diastolic pressure above 90. The systolic pressure is always the higher number and usually expressed first in blood pressure readings. Isometric, or static, exercises are those in which your muscles are contracting without any movement such as pushing against a wall or holding a yoga pose.
Effects
According to the American College of Sports Medicine or ACSM, isometric exercise elevates blood pressure and can be dangerous in some cases for hypertensive individuals. When you exercise, your heart pumps more oxygen-rich blood to the working muscles, making your blood vessels crowded like the highway at rush hour. With isokinetic -- moving -- exercises, your artery walls expand to make room for the extra blood flow. However, according to a study published in the American Journal of Hypertension, your artery walls don’t expand as much during isometric exercises despite the elevated blood flow. When your arteries don’t expand, your blood pressure increases.
Warning
Isometric exercises using your core or trunk muscles such as the plank pose are especially dangerous for those with hypertension because they can increase pressure around vital organs. Holding your breath while you do isometric exercises is especially dangerous for people with high blood pressure because forced exhalation into a closed throat -- known as the Vasalva maneuver -- causes an additional spike in blood pressure. ACSM recommends that individuals with a resting systolic blood pressure higher than 200 or a diastolic blood pressure higher than 110 should first talk to a doctor about how to structure an exercise program.
Time Frame
Elevated blood pressure from exercise only lasts for as long as you are exercising, and may actually drop immediately after exercise. Because the walls of your blood vessels dilate during exercise to make room for the excess blood flow, it takes time for the blood vessels to contract again when you stop moving. Because less blood is flowing through the expanded veins and arteries, pressure against your artery walls drops.
Prevention
While doing isometric exercises, focus on breathing in and out in a controlled way. Don’t hold your breath or breathe too quickly. The same suggestion goes for hypertensive athletes who are doing other kinds of weight lifting. Breathe out during the “contraction” or “up” phase when the muscle is getting shorter and inhale during the eccentric or “down” phase when the muscle gets longer.
Hand Grip
The medical field sometimes uses isometric exercises in a clinical setting to reduce a patient’s blood pressure. A University of Georgia study found that isometric hand-grip training reduced resting diastolic blood pressure or the pressure in your blood vessels between heart beats. Isometric hand grip exercises include exercises hanging from a bar such as a pull-up bar or holding on to a heavy weight.
References
- ACSM's Resources for the Personal Trainer; American College of Sports Medicine; 2006
- "American Journal of Physiology Heart and Circulatory Physiology"; Isometric Handgrip Training Reduces Arterial Pressure at Rest Without Changes in Sympathetic Nerve Activity; Ray and Carrasco; 2000
- "American Journal of Hypertension"; Effect of Isometric Exercise on Large and Small Arterial Compliance in Healthy, Normotensive Men and Women; Hasnain et al; 2004
