Kenneth Gardner
OUR BLOOD pressure is the measurement of the force that the blood exerts on the wall of the arteries. Blood pressure is represented by two numbers, the systolic pressure which represents the pressure of the blood when the heart contracts and diastolic pressure, the pressure when the heart relaxes.
The normal blood pressure for adults is considered to be a systolic pressure of 120 and a diastolic pressure of 80. Systolic readings below 120 are considered to be ideal. Such readings can be achieved with the use of medication. Systolic readings below 120 are also enjoyed by many persons who have achieved high levels of physical fitness via regular physical exercise. On average, our resting blood pressure increases with age. Our lifestyle and environment are also important determinants of our blood pressure.
Various strategies for both preventing and treating high blood pressure (hypertension) have been developed. Systolic readings of140 and above and diastolic readings of 90 and above are termed as high blood pressure/hypertension .
PRIMARY PREVENTION
A variety of medications have been used for the primary prevention of hypertension. Adjunct to the pharmacologic therapy for persons with hypertension are weight reduction, the restriction of sodium intake, exercise and behaviour management for relaxation or stress reduction. Essentially hypertensive medications have adverse side effects that disrupt other systems' functions that may negate the positives that we experience.
The effects of exercise on our body induces increased blood or a hypertensive response. During our recovery from exercise, all things being equal, we experience a dramatic decrease in the systolic blood pressure or a hypotensive response. The increase in blood pressure during exercise is due to the increase activity level of the body and its impact on our heart contraction. However, there is little change, if any, in the blood pressure when the heart is relaxed. Therefore, there is no increase in the after load of the heart, thus exercise-induced hypertension is not detrimental to the function of a healthy heart.
HEART DAMAGE
However, chronic exposure of the heart and its blood vessels to increased blood pressure above the systolic pressure of140 and the diastolic pressure of 90 can cause damage to the heart, its blood vessels and the organs they perfuse. A decrease in blood pressure, below the normal resting values or hypotension, could occur during the immediate recovery from exercise. This could be potentially dangerous, thus the need for the cool down routine especially following intense exercise. Exposure to hypotension often coincides with reduced blood return to the heart which in turn decreases blood flow to the brain. This could result in fainting.
Our blood pressure is regulated by complex interactions among the nervous system, hormones, functions of the kidneys, the heart and its blood vessels. The primary determinants of blood pressure are the heart and its vessels and they are impacted positively by regular exercise. Exercise helps to hone the functions of the systems of the body, which are important especially during undesirable changes that risk immediate alterations in our blood pressure regulation.
For individuals with hypertension, the use of diet and exercise are frequently used in its reduction; this has been validated by the American College of Sports Medicine. The exercise is best if it involves the use of large muscle groups and performed for 20 to 60 minutes duration at moderate intensity for three to five days per week. For individuals with normal blood pressure continued involvement in endurance exercise has been shown to provide a protective effect against the development of hypertension.
Kenneth Gardner is an exercise physiologist at the G. C. Foster College of Physical Education; email: yourhealth@gleanerjm.com.
