Blood Pressure, Cholesterol And Your Heart
Blood Pressure, Cholesterol And Your Heart
Rose Marie Robertson, MD, FAHA, FACC, FESC (Chief Science Officer and Past President of the Board of American Heart Association) gives expert video advice on: How is blood pressure measured?; What is a safe range for my blood pressure?; How do I lower my cholesterol? and more...
How is blood pressure measured?
We measure the blood pressure at two times. We measure it when the heart beats; we call that systoli, or the systolic blood pressure, that's the top number of the blood pressure, and when the heart is in between beats, we call that diastoli, so we measure the diastolic blood pressure, or the lower number. If your blood pressure is really normal, it should be less than 120 over 80. Any blood pressure between 120 to 139 is in an area where we talk about and call it pre-hypertension. That means you have the chance of developing high blood pressure, or hypertension, and likewise for the bottom number, if the bottom number is anything between 80 and 89, you have pre-hypertension.
What is a safe range for my blood pressure?
A safe range for your blood pressure is to be certain that you keep it below 14/9. That means you don't have high blood pressure. If you, on the other hand, have other risk factors for coronary heart disease like diabetes or if you have kidney failure or heart failure, you probably want to keep your blood pressure less than 13/8. Normal blood pressure is actually less than 12/8. So normal blood pressure is lower than we used to think. We used to think of 12/8 as the normal blood pressure where everybody should be. We now know that people between 12/8 and 13/8 are in what we call the pre-hypertensive range meaning they have high blood pressure and need to be very careful about lifestyle manoeuvres. They need to work to make sure that they don't have their already high blood pressure rise over time and that they may need medication in addition as blood pressure tends to rise with age.
What is "cholesterol"?
Cholesterol is a waxy substance that we find in the bloodstream and actually as part of cells. So it's a part of the fats that are in the body, fats that we call lipids. Cholesterol is actually an important building block of our cells, it's an important part of cell membranes, it's used to make some hormones, as part of our normal biochemistry. So we need to have cholesterol, and the body actually can make its own. On the other hand, we don't need to have excessive cholesterol circulating in our blood. Because if it does circulate in the blood, it gets taken up into our blood vessel walls, and causes the plaque we now refer to as atherschlerosis, or hardening of the arteries. Cholesterol, because it's a fat, can't actually dissolve in blood just the way oil can't dissolve in water. But it's carried around in the blood by special chemicals called lipoproteins. Those lipoproteins are important. You know some of them, probably. We call 'the good cholesterol HDL, or high-density lipoprotein, and that's a lipoprotein that we think of as carrying the cholesterol away from the blood vessel wall and getting rid of it, primarily through the liver. The bad cholesterol, or low-density lipoprotein, LDL, is the lipoprotein that carries cholesterol and acutally allows it to be absorbed into the blood vessel wall, where plaque is then increased in its amount and blood flow through vessels is threatened.
What is a safe range for my cholesterol level?
Cholesterol is one of the very important risk modifiable factors for coronary heart disease so it is important to know your cholesterol numbers, and then try make them as close to perfect as you can. The perfect cholesterol level, however, varies on the person and it depends on how much risk you're at generally. So, we think it is very important to see a healthcare provider and have them add together all the different potential risk factors you have. Do you smoke? Is your blood pressure high? What's your family history, your age, and your gender? Your health care provider will put all that information together and assess your risk. If you are at a low risk, which means you have less than two cardiovascular risk factors and neither of them is too high, then your LDL cholesterol (which is our goal because that is the bad cholesterol) can be up to 160; we like it to be lower but you don't really need to do anything aggressive about it at that level. If you have more than two risk factors, then we don't want it above 130 for sure. If you have coronary heart disease, or have enough risk that we would say you have a coronary disease risk equivalent (and that includes something as simple as just having diabetes) and you have no other risk factors, then we want your LDL cholesterol (the bad cholesterol) to be less than 100. If you have coronary disease and are at high risk, then in that case it's a therapeutic option. That is, your doctor may decide to bring your LDL cholesterol down to below 70. So, we look for lower levels than we used to and we think that's quite important in reducing the risk.