Simply put, blood pressure is a result of the force of the blood in the blood vessels as it is pumped by the heart. The blood pressure is measured in two phases; systolic (when the heart pumps) and diastolic (when the heart relaxes). The blood pressure readings are therefore given as two figures, the systolic over the diastolic, all expressed in millimeters of mercury (mmHg). Blood pressure readings of more than 140mmHg systolic and 90mmHg diastolic are considered elevated, which is the definition of hypertension. Blood pressure is however classified depending on the specific figures as follows:
- Normal blood pressure – systolic less than 120mmHg and diastolic less than 80mmHg
- Pre-hypertension – systolic 120-139mmHg and diastolic 80-89mmHg.
- Stage 1 hypertension – systolic 140-159mmHg and diastolic 90-99mmHg
- Stage 2 hypertension – systolic 160 and above; diastolic 100 and above.
Hypertension may be primary or secondary. Secondary hypertension is caused by other medical conditions and accounts for less than 10% of the hypertension cases. The concern is primary hypertension which accounts for up to 90% of the cases, and is associated with risk factors that can be prevented.
Hypertension is often referred to as the ‘silent killer’ due to the fact that it may be present but without any symptoms. It causes deaths as a result of the complications associated, which may be discovered once they have already developed. These life-threatening complications include:
- Heart disease including enlargement of the heart, heart attacks and heart failure
- Kidney failure
- Aneurysms – swelling of the blood vessel wall which can rupture with heavy bleeding.
Other complications include visual impairment and blindness.
Hypertension has been increasing as the lifestyle patterns have been changing; initially it was mainly a disease of the developed world but it is now increasing in developing countries. The prevalence in Kenya in 2008 was estimated at 37% (WHO, 2010), a figure that has continued to rise. And yet hypertension is a lifestyle disease whose risk factors are amenable to lifestyle changes as follows:
- Body weight – achievement and maintenance of ideal body weight reduces the risk of hypertension. For patients who are overweight, a reduction in the body weight of about 10kgs reduces the systolic blood pressure by 5 to 20 points.
- A diet low in fats, sugars and salt helps reduce blood pressure.
- Increase intake of vegetables to the recommended 4 to 6 servings per day. These include green vegetables, broccoli, carrots and tomatoes.
- Intake of 4 to 6 servings of fruits per day. These are rich in fiber, magnesium, potassium and other vitamins which have been associated with a reduction in blood pressure.
- Reduce intake of dairy products and change to low-fat dairy products. It is recommended to have 2-3 servings of low-fat dairy products such as milk, yoghurt, cheese which are rich in calcium and are a source of protein. Calcium intake is associated with lower blood pressure.
- Reduce intake of red meat and eat more fish, poultry and nuts as source of protein.
- Intake of whole grains – at least 6 to 8 servings of foods such as pasta, cereal and bread.
- 4 to 5 servings of nuts and legumes such as peanuts, peas, lentils, beans etc. are a source of magnesium and potassium, which reduce blood pressure.
- Reduce the amount of alcohol to one standard drink per day, which is approximately half a pint of beer, a tot of spirits or a small glass of wine.
- Stop smoking.
- Engage in some form exercise lasting 30 minutes at least 5 days per week. This coupled with the dietary measures above should help control body weight.
These lifestyle changes do not only apply to the prevention of hypertension, but are also the first line in the treatment of hypertension. Some cases of hypertension can be controlled purely by these lifestyle interventions but in many cases, medication is necessary. Treatment will also include screening for other conditions that commonly occur with hypertension and that may affect its control. This includes conditions like diabetes and elevated cholesterol. As we have seen, the risk factors for these lifestyle diseases tend to be similar, and thus it is not uncommon to find these diseases occurring together. The presence of more than one compounds the risk of complications. Screening and treatment for other lifestyle diseases is therefore part of the treatment of one.
Lifestyle diseases are associated with life-threatening complications, which can be avoided since these diseases are largely preventable. The lifestyle changes need to be instituted as early as childhood if we are to curb the increase in these diseases.