The contraction and relaxation phases of the heart, which are called systole and diastole, respectively, cause the entry and subsequent release of blood from the aorta. When the heart contracts, blood flows into the aorta, where it is temporarily stored until it is released into the peripheral vessels. Your blood pressure results from this stored blood in the aorta creating pressure within the entire arterial system. This causes a pressure wave to travel down the arteries branching off the aorta, which results in two measurements: diastolic blood pressure and systolic blood pressure.
Diastolic Blood Pressure
During diastole, arterial blood pressure decreases to 70 or 80mmHg in an individual with normal blood pressure at rest. This is referred to as the diastolic blood pressure, which indicates the ease with which blood flows from the arterioles into the capillaries. The higher the resistance, the slower the pressure in the arteries decreases, remaining elevated longer. This causes a higher diastolic reading, which is the bottom number in a blood-pressure measurement.
Systolic Blood Pressure
During systole, arterial blood pressure increases to around 120mmHg, which is referred to as systolic blood pressure. This represents an estimation of the work of the heart and the force against the arterial wall that the blood exerts. If the heart has to exert a greater amount of force to pump the blood, the higher the systolic reading is going to be, which is the top number in a blood-pressure measurement.
Diastolic Blood Pressure Response During Exercise
While you exercise, your blood pressure reflects the changes in intensity levels and demand for blood and oxygen by the working muscles. These changes are seen mainly in the systolic pressure, as the diastolic pressure remains relatively unchanged, or it may even decrease slightly. This often concerns people, as they see their systolic blood pressure rise and no change or a decrease in their diastolic pressure. However, this is a normal and healthy response to exercise.
Exercise Effects On Diastolic Blood Pressure
Chronic bouts of exercise, whether for cardiovascular or strength training, will lower blood pressure over time. If you have hypertension--which is associated with an impairment of the left ventricle during diastole--exercise can improve your diastolic blood pressure and left ventricular function, especially when reducing abdominal obesity.
Considerations
If you have hypertension, especially Stage 3 level or higher, where your blood pressure is greater than 180/110 while at rest, ease into your exercise routine, and minimize very heavy lifting. Along with exercise, the next beneficial way to reduce your blood pressure, systolic and diastolic collectively, is having a healthy diet that incorporates foods with less salt and saturated fat.
References
- "Exercise Physiology: Energy, Nutrition, and Human Performance"; William D. McArdle, Frank I. Katch, and Victor L. Katch; 2007
- "Medicine and Science in Sports and Exercise"; Exercise Effects on LV Diastolic Function: Relationships to Changes in Fitness, Fatness, and Blood Pressure; Kerry Stewart, Pamela Ouyang, Anita C. Bacher, Sandra Lima, and Edward P. Shapiro; May 2006
