Diseases that hide in your blood

Blood pressure is determined both by the amount of blood your heart pumps and the amount of resistance to blood flow in your arteries. The more blood your heart pumps and the narrower your arteries, the higher your blood pressure. A blood pressure reading is given in millimeters of mercury (mm Hg). It has two numbers.

Top number (systolic pressure) - the first, or upper, number measures the pressure in your arteries when your heart beats.

The bottom number (diastolic pressure) or the second, or lower, number measures the pressure in your arteries between beats.

You can have high blood pressure for years without any symptoms. Uncontrolled high blood pressure increases your risk of serious health problems, including heart attack and stroke. Fortunately, high blood pressure can be easily detected. And once you know you have high blood pressure, you can work with your doctor to control it.

Most people with high blood pressure have no signs or symptoms, even if blood pressure readings reach dangerously high levels. A few people with high blood pressure may have headaches, shortness of breath or nosebleeds, but these signs and symptoms aren't specific and usually don't occur until high blood pressure has reached a severe or life-threatening stage.

There are two types of high blood pressure.

Primary (essential) hypertension - For most adults, there's no identifiable cause of high blood pressure. This type of high blood pressure, called primary (essential) hypertension, tends to develop gradually over many years.

Secondary hypertension - Some people have high blood pressure caused by an underlying condition. This type of high blood pressure, called secondary hypertension, tends to appear suddenly and cause higher blood pressure than does primary hypertension. Various conditions and medications can lead to secondary hypertension, including: obstructive sleep apnea, kidney disease, adrenal gland tumors, thyroid problems; certain defects you're born with (congenital) in blood vessels; certain medications, such as birth control pills, cold remedies, decongestants, over-the-counter pain relievers and some prescription drugs as well as illegal drugs such as cocaine and amphetamines.

High blood pressure has many risk factors, including:

· Age. The risk of high blood pressure increases as you age. Until about age 64, high blood pressure is more common in men. Women are more likely to develop high blood pressure after age 65.

· Race. High blood pressure is particularly common among people of African heritage, often developing at an earlier age than it does in whites. Serious complications, such as stroke, heart attack and kidney failure, also are more common in people of African heritage.

· Family history. High blood pressure tends to run in families.

· Being overweight or obese. The more you weigh, the more blood you need to supply oxygen and nutrients to your tissues. As the amount of blood blow through your blood vessels increases, so does the pressure on your artery walls.

· Not being physically active. People who are inactive tend to have higher heart rates. The higher your heart rate, the harder your heart must work with each contraction and the stronger the force on your arteries. Lack of physical activity also increases the risk of being overweight.

· Using tobacco. Not only does smoking or chewing tobacco immediately raise your blood pressure temporarily, but the chemicals in tobacco can damage the lining of your artery walls. This can cause your arteries to narrow and increase your risk of heart disease. Secondhand smoke also can increase your heart disease risk.

· Too much salt (sodium) in your diet. Too much sodium in your diet can cause your body to retain fluid, which increases blood pressure.

· Too little potassium in your diet. Potassium helps balance the amount of sodium in your cells. A proper balance of potassium is critical for good heart health. If you don't get enough potassium in your diet, or you lose too much potassium due to dehydration or other health conditions, sodium can build up in your blood.

· Drinking too much alcohol. Over time, heavy drinking can damage your heart. Having more than one drink a day for women and more than two drinks a day for men may affect your blood pressure.

· Stress. High levels of stress can lead to a temporary increase in blood pressure. Stress-related habits such as eating more, using tobacco or drinking alcohol can lead to further increases in blood pressure.

· Certain chronic conditions. Certain chronic conditions also may increase your risk of high blood pressure, including kidney disease, diabetes and sleep apnea.

Although high blood pressure is most common in adults, children may be at risk, too. For some children, high blood pressure is caused by problems with the kidneys or heart. But for a growing number of kids, poor lifestyle habits — such as an unhealthy diet and lack of exercise — contribute to high blood pressure.

The excessive pressure on your artery walls caused by high blood pressure can damage your blood vessels as well as your organs. The higher your blood pressure and the longer it goes uncontrolled, the greater the damage.

Source: Mayoclinic.org