Understanding Blood Pressure Readings
There are two numbers to a blood pressure reading and both are important:
- The top number is the systolic blood pressure. It measures how hard the blood is hitting against the artery wall while the heart is contracting.
- The bottom number is the diastolic blood pressure. It measures how hard the blood is hitting against the artery wall while the heart is relaxing between the beats.
Taking a Blood Pressure Reading
To check blood pressure, a cuff is placed around the arm. It is important for the cuff to fit the arm correctly. A stethoscope is placed on the skin below the cuff, over an artery.
- The cuff is pumped up with air so that it tightens on the arm. Then the air is slowly let out. Sounds are heard through the stethoscope as the blood pushes back through the arteries. The very first sound heard is the systolic blood pressure.
- When the sound disappears, this is the diastolic blood pressure.
Some blood pressure machines can detect these measurements automatically without the need for anyone to listen with a stethoscope.
Since blood pressure can be influenced by anxiety, time of day and other everyday factors, it is important to measure your blood pressure on a couple different days.
Normal Blood Pressure for a Child
The normal blood pressure measurement for a child depends on three factors: age, gender and their height/weight. At age 18, normal adult blood pressure measurements are used
High Blood Pressure (Hypertension)
Those with high blood pressure have an excessive force of blood flow against the walls of their blood vessels. "Hypertension" means high blood pressure, or a blood pressure greater than the 95 percent for age, weight and height.
All children with blood pressure over 120 / 80 need monitoring as they are at risk for developing hypertension (also known as prehypertension). It typically takes more than one measurement to diagnose hypertension. However, if the blood pressure is severely high, a diagnosis may be made. A pattern of high blood pressure helps establish a diagnosis of hypertension.
The guidelines published by the government in 2017 recommended an echocardiogram (heart test) on all children before starting hypertension medicine due to the risk for organ damage.
Reasons for High Blood Pressure
The most common reason for high blood pressure is the inherited (genetic) form known as primary hypertension. This accounts for the majority of cases with hypertension in both adults and children. The cause of primary hypertension is unknown. Children and adolescents with primary hypertension are often overweight.
The remaining cases with high blood pressure are due to an underlying cause, such as a kidney issues, narrowing of the arteries to the kidneys, a congenital defect of the heart such as coarctation of the aorta, or rare tumors of the adrenal gland. When there is another issue causing the high blood pressure, it is called secondary hypertension.
Effects of High Blood Pressure
High blood pressure increases the workload of the heart, since it must squeeze blood through the blood vessels against high pressure. When the heart must pump harder, the pumping chamber (left ventricle) of the heart may become enlarged and thickened.
If high blood pressure continues to go unnoticed or untreated, the left side of the heart can become progressively larger or thicker (left ventricular hypertrophy). This is one of the risk factors for developing coronary artery disease and possibly a heart attack.
If high blood pressure is not treated, it can also damage the arteries in the kidneys causing them to narrow and decrease the blood supply to the kidneys. The kidneys cannot function normally and this may result in kidney failure.
Uncontrolled high blood pressure over time can also harm the arteries that bring blood to the brain. Prolonged high blood pressure can cause the vessel walls to weaken and even possibly burst, causing bleeding in the brain (stroke). The opening of the artery may narrow or become blocked completely. In this case, blood is unable to get to the brain. This is another kind of stroke.
Uncontrolled high blood pressure can also damage the eye by causing the arteries to narrow and twist, thus cutting off the blood supply. Eventually this can lead to vision problems.
It is important to remember that heart attacks, kidney failure and strokes from hypertension are uncommon in children and adolescents. However, the processes that lead to these problems probably do begin in childhood. This is why children and adolescents should have their blood pressure measured with routine healthcare visits.
Signs and Symptoms of High Blood Pressure
Hypertension is known as a silent killer because it usually has no signs and symptoms. Most patients with hypertension feel fine and do not know that their blood pressure is elevated.
When hypertension is very severe or advanced, symptoms may include headache, fainting and loss of kidney function. In late stages, convulsions may occur.
Treatment for High Blood Pressure
If blood pressure is high, measuring it again is important. If the blood pressure remains high, we recommend the following changes:
- Achieving the proper weight through diet and exercise for patients who are overweight
- Cutting down on salt in the diet
Nutrition labels list sodium content in milligrams (mg).
Americans typically take in 5,000 to 8,000 mg of sodium per day. If blood pressure is high, it is best to reduce sodium intake to 2,000-3,000 mg / day. A teaspoon of salt has 2,196 mg of sodium. The major sources of sodium in your diet are:
- Salt added to food during cooking and at the table
- Sodium added to food during processing (hidden salt)
- Sodium which naturally occurs in food and water
To reduce sodium in your diet, remove the salt shaker from the table and avoid adding it during meal preparation. Herbs and spices can be a tasty alternative. In addition, limit the amount of processed foods your family eats.
Processed lunch meats, bacon, sausage, cheese, convenience foods and most canned foods are high in sodium. Many snack foods, including crackers, chips and baked goods, are also high in sodium.
Some sodium occurs naturally in foods, such as meats, poultry, seafood and dairy products, as well as minimal amounts in fresh vegetables and fruits. These do not need to be limited.
Look at the labels! Try to balance out the sodium in your family's meals and snacks. When eating out, avoid sauces and ask the server to prepare your meal without salt.
Certain types of restaurants, including Asian and Mexican restaurants, are particularly high in sodium, but will usually change your food to meet your needs.
Avoiding smoking, excessive caffeine, and a lot of alcohol are other lifestyle changes that may help decrease blood pressure.
When all else fails or if blood pressure is moderate to severe, then antihypertensive medication may be used.
Children do not usually suffer the life-threatening cardiovascular effects of high blood pressure. The negative effects of hypertension usually develop over many years. Finding it early allows us to find the appropriate ways to address it and lower the blood pressure.