Blood Pressure

High blood pressure, low blood pressure, what are you saying, doctors? What is blood pressure and why should we care?

What is blood pressure?

Blood pressure is the pressure that your blood exerts on the blood vessels. I know…. that’s a bit redundant.

Let me explain blood pressure a bit more, so you can visualize this. From what we’ve learned in school, the molecules in fluids interact closely with one another, meaning that they will not fill the entirety of a container unless you’ve placed enough of that fluid into the container to fill it completely. Each molecule exerts its own amount of force on each other and on the portion of the surface of the container that it interacts with.

Pressure is defined as a force exerted on a particular area. So the amount of force that the molecules exert on a particular portion of a container’s surface is equivalent to the pressure exerted by the molecule onto the container.

Now, if you replace the fluid with blood serum,the molecules with blood cells and the container with blood vessels, you’ll have the same situation; the blood cells each exert its own amount of force on portions of the blood vessel, which is the blood pressure.

Blood pressure naturally increases when your heart contracts to push blood into the blood vessels, and decreases when your heart relaxes.

Why is blood pressure important?

Blood pressure determines how hard your heart has to work to continuously feed your circulatory system with blood. The harder your heart works, the more strain there is in your circulatory system. This can lead to higher risk for health problems.

It’s also important to note that there are a variety of factors that affect blood pressure including how active you are, how much rest you get, your body temperature, diet, posture, medications and even your emotional state. So it’s important to try and stay healthy and active, for your heart and your health!

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Cholesterol – Bad?

Last week, we talked about the good side of cholesterol, which we don’t really hear about. No, instead we hear about the evils of cholesterol and how it can lead to heart disease. But cholesterol seems to help us out a lot, so what makes it so bad?

Types of Cholesterol

There are two ‘types’ of cholesterol. I use ‘types’ but it’s really the type of transport that the cholesterol uses that differentiates one ‘type’ from the other.

You see, cholesterol requires a transport system between the liver, where it is predominantly produced, and other cells because cholesterol is insoluble. The transporters for cholesterol are lipoproteins. Lipoproteins are molecules that consist of a mix of lipids and proteins. The lipid portion of the lipoprotein can interact with the cholesterol, while the protein portion allows the complex to travel in the bloodstream.

There are two different transporters that transport cholesterol; LDL and HDL. LDL stands for Low-Density Lipoprotein while HDL stands for High-Density Lipoprotein. LDLs transport cholesterol from the liver to the other cells in the body, while HDLs transport cholesterol from the cells of the body to the liver.

“Bad Cholesterol”

This refers to cholesterol that is being transported by LDLs. Since the LDLs carry the cholesterol from the liver to the cells, which have a lower storage capacity for cholesterol, there is the possibility of the build-up of the LDLs (and cholesterol) in your bloodstream if you have more cholesterol in your bloodstream than is required for your cells. The build-up will occur on the walls of the arteries that lead to your heart and brain. Too much build-up can result in the formation of a clot, which can induce heart attacks or strokes.

They’re not all bad…

HDL is the superhero of lipoproteins. It’s like the older sibling that looks out for their younger sibling, slowly cleaning up any mess they make. HDLs carry cholesterol from the cells and the bloodstream back to the liver, where it can be broken down into bile and then stored in the gallbladder. On their way, they can help clean up the LDLs’ messes by grabbing them and dragging them back to the liver, where the cholesterol is deposited for further storage. This reduces the amount of LDL in the bloodstream, reducing the build-up in your blood and reducing your risk of heart disease. This is probably why HDLs are referred to as “Good cholesterol”.

LDLs are larger than HDLs, which is probably why the former causes clots whereas the latter doesn’t.

Lowering your Risk

You produce LDLs and HDLs naturally. While you can’t control exactly how much your body produces, you can control what you eat as it was found that certain fats stimulate the production of LDLs.

The American Heart Association’s Nutrition Committee strongly advises these guidelines for people over the age of two:

  • Limit total fat intake to less than 25–35 percent of your total daily calories (TDC)
  • Limit saturated fat intake to less than 7 percent of TDC
  • Limit trans fat intake to less than 1 percent of TDC
  • The remaining fat (17-27% of TDC) should come from sources of monounsaturated and polyunsaturated fats
  • Limit cholesterol intake to less than 300 mg per day, for most people.  If you have coronary heart disease or your LDL cholesterol level is 100 mg/dL or greater, limit your cholesterol intake to less than 200 milligrams a day.

Your physician can check your cholesterol levels by performing a blood test. You want to keep your LDL levels below 130mg/dL and your HDL levels ideally above 60mg/dL. You want low LDL levels and high HDL levels to reduce your risk of heart disease. If you have high LDL levels (the dreaded “high cholesterol”) and/or low HDL levels (the dreaded “low cholesterol”), then you’re going to want to look into dietary and lifestyle changes.

So, it looks like cholesterol can be the good guy or an accomplice depending on who it’s traveling with. Or, I suppose it could be considered a bystander. But now you know that bad cholesterol doesn’t really have to do with the cholesterol itself, but rather its ride.

 

American Heart Association. 2013. Know Your Fats. Heart.org. <http://www.heart.org/HEARTORG/Conditions/Cholesterol/PreventionTreatmentofHighCholesterol/Know-Your-Fats_UCM_305628_Article.jsp> May 30, 2013.