Understanding Your Heart

Understanding your Heart

This article is all about understanding your heart. I am going to try and keep this simple, the main purpose of these articles is to help with your understanding. I remember being sat in University lectures and having a bunch of complicated and fancy words thrown at me which just confused me to the point where I stopped listening and decided when I got home to try and teach myself. So, my aim if for this not to happen to you.

As you may already know your heart is roughly the size of your fist and sits in the middle of your chest slightly to the left. Its job is to send blood around your body providing your body with all the oxygen and nutrients it needs. It also removes waste products such as carbon dioxide. Each day your heart beats about 100,000 times and it continuously pumps eight pints of blood around your body.

I’ve tried to do this in a way this simplifies your heart anatomy. I could go into more detail but for the purposes of this I am trying to do it in a way that helps you understand. Your heart is made up of 4 chambers. I want you to think of a box which has two lines going through the centre, one vertical and one horizontal splitting the box into 4 equal boxes. The top two boxes are your atria and the bottom two are your ventricles. In the right top corner, we have the right atrium, in the top left box we have the left atrium. These are responsible for receiving blood and passing the blood down into your ventricles. So, in the right bottom box is the right ventricle and the left bottom box we have the left ventricle. Your ventricles pump blood out and away from your heart. The left and right side of your heart is separated by a thin muscular wall called the septum which runs down the middle of your heart. So, we have the 4 chambers and the septum down the middle. I hope I haven’t lost you yet. If it makes it easier you can draw this out as we go.

We’ll carry on.

In the right hand side boxes, we have the right atrium and right ventricle, now these are separated in the middle by an atrioventricular valve called the tricuspid valve. When the blood flows from your right atrium down to your right ventricle this valve ensures that the blood doesn’t flow backwards. Similarly, on the left hand side we have the two chambers which are separated by the bicuspid or mitral valve. Which for the purposes of this I am going to call the bicuspid because bicuspid and tricuspid are easier to remember then mitral and tricuspid. And again, this valves ensure the blood only flows one way.

Some people watching this may have a leaky valve or have valve problems which can come from a few different things such as these valves becoming to floppy (for want of a better word). The valve not opening as wide as it should or the valve leaking and the blood flowing the wrong way and the scary thing about this is that there isn’t really a way of knowing without going through testing. I’ve had clients with this problem and for a while they were wondering why they were becoming more breathless or tired and couldn’t put a finger on what is was.

Back to your heart. The right side of your heart pumps blood to your lungs whereas the left side pumps oxygenated blood (blood with oxygen in it) around your body. This is why the left side of your heart tends to be slightly bigger than the right because it has to pump blood further around your body.  Moving onto my last point in this section, on the right side we have the pulmonary valve which takes blood from your right ventricle to your lungs. On the left side we have the aortic valve which allows blood from your left ventricle to the rest of your body.

That brings us to the end of this article, that was quite information heavy I know. I hope that did not confuse you too much. I am fully aware that there’s parts I left out but as I said at the start, I wanted a simplified version aiming to help you understand your heart a bit better. The next article is about the flow of blood through your heart.

Blood Flow

Before we get started, I need to tell you about veins and arteries. Quite simply, veins return deoxygenated blood back to your heart and arteries carry oxygenated blood from your heart to the rest of your body.

In the last article I spoke a little bit about the anatomy of your heart and spoke about the 4 chambers and some valves. We are going to start with the left side of your heart in the left ventricle. Blood enters the left ventricle from your left atrium through the bicuspid valve. Once the left ventricle is filled blood is ejected passing through the aortic valve into your aorta which sits at the top of your heart. From here the blood is circulated to all parts of your body via your arteries. Once the blood full of nutrients and oxygen has been delivered to the working muscles it returns back to your heart via your veins. Remember veins return blood back to your heart.

The blood returns back to your right atrium and passes through the tricuspid valve (separating your right atrium and right ventricle) into your right ventricle. From here the blood is forced out to your lungs where it is oxygenated. From your lungs it travels back to your left atria and is forced through the bicuspid valve into your left ventricle and the cycle starts all over again.

Now that is a very simplified version, but I think it makes the most sense. There’s a couple of different valves and arteries that I left out but unless your studying for a test you do not really need to know the names of these. I hope that helped to give you a better understanding of how the blood travels from your heart to the rest of our body and back again and I hope that helped give you a slightly better understanding of how your hearts works. Thank you for reading.

Heart Rate – Tachycardia & Bradycardia

Heart rate, quite simply, is the number of times your heart beats per minute and this will vary throughout the day depending on what you are doing. When resting your heart rate will be lower than when you are active.  We aim for 60-80 beats per minute (bpm), preferably closer to that 60 bpm mark. Anything over 80 bpm puts additional strain on your heart making it work harder. Its important to keep an eye on your heart rate throughout the day. You should make a note of your resting heart rate and you can compare your heart rate to this when you are doing different activities.  I have done a video in the exercising safely section of the exercise centre all about heart rate and how to measure your heart rate. This section will give you more information on what happens when your heart goes too high or too low.

Anything over 100 bpm at rest is known as tachycardia which can potentially be dangerous. This means that your heart is working harder than normal. When your heart beats too rapidly it pumps less efficiently and blood flow to the rest of your body and back to your heart is reduced. Symptoms of this include a rapid pulse rate, chest pain, shortness of breath and light headedness. If you experience these symptoms and think it could be a result of a fast heart rate you should stop what you’re doing and sit down in an attempt to let your heart rate drop. If this lasts longer than a few minutes, call 999. 

If we flip this around, a heart rate slower than 60 bpm is known as bradycardia. This is common when people are resting or asleep. Individual’s who are physically active tend to have slower heart rates as their heart is stronger and more efficient. For many people, bradycardia isn’t a problem. However, if you start feeling faint, lightheaded, experience palpitations or finding yourself out of breath and it harder to exercise these are all symptoms of bradycardia and you should consult with your GP. You can also check your HR using the instruction video I have uploaded in the exercise section.

Blood Pressure

Now I’m sure many of you will understand and know what blood pressure is. But just in case you don’t, quite simply, blood pressure is a measurement of the force your heart uses to pump blood around your body.

You may have seen your blood pressure reading as one number over another. For example, 120 over 80. The first or higher number is your systolic blood pressure which is the pressure when your heart squeezes and pushes blood around your body. The second number is your diastolic blood pressure which measures the force of blood against your artery walls as your heart relaxes and your ventricles refill with blood.

We are aiming for a reading below 130/80 and preferably closer to 120/ 80. The higher this is the more strain this puts on your heart. Any reading over 130/90 is known as prehypertension and anything higher than this could be hypertension. If your blood pressure is too high, it puts extra strain on your blood vessels, heart and other organs. Persistent high blood pressure can increase your risk of a heart attack. If you have high blood pressure, reducing it even a small amount can help lower your risk of these health conditions.

On the other hand, low blood pressure known as hypotension (po=low) can be more dangerous than high blood pressure especially in those of us who are slightly older. Low blood pressure is a reading of less than 90/60mmHg. Symptoms of this include light-headedness, dizziness, feeling sick, fainting and generally feeling weaker. This might mean your blood pressure is too low and it is important that you speak to your local GP about this. Bare in mind, your blood pressure can vary depending on the time of day. It gradually increases throughout the day. What you are doing and how you’re feeling can also affect it. There are many possible causes of low blood pressure and it may just be low because you’re fit and healthy.

All adults over 40 are advised to have their blood pressure checked at least every 5 years. You can get your blood pressure tested at your GP surgery or you can check your blood pressure yourself with a home blood pressure monitor.

Target Heart Rate

I want to tell you a little bit now about your target heart rate which is the range of beats per minute you should aim for during exercise. It’s recommended that this is between 40 and 70 percent of your maximum heart rate. Anything lower than this means you may not be getting the full benefits from exercise and if you go above 70% it doesn’t really matter, this is just what’s recommended and I wouldn’t want to keep you above 70% over a longer period of time because there isn’t really any need. So, your target heart rate is two numbers that you should aim for your heart rate to be between when exercising. For example, if your target heart is 90-110 beats per minute, when your exercising you should aim for your heart rate to be between these two numbers. I hope that makes sense.

I think it is important for you to know roughly what your heart rate should be when your exercising. In the classes I run, I take peoples heart rate at the beginning of the class, in the middle and at the end and people know roughly what their heart rate should be at these stages. So we expect it to be close resting at the start of exercise, in the middle when we have been exercising and hopefully working hard we expect this to be higher and then after the cool down at the end of the class we expect it to be dropping back down to resting. It occurred to me that instead of me telling them where there heart rate should be and taking it for them it is important that I teach them how to take their heart rate and know roughly where their heart rate should be during exercise. So, it also makes sense for me to show you how to do this.

There are a few different ways. The first one is on the British heart foundation website called the target heart rate calculator and this is a quick and easy way of getting a rough estimate. If you type BHF target heart rate calculator it should come up. I will add a link at the bottom of this page. Keep in mind you only have to input your age so it isn’t the most accurate reading and doesn’t take into account any medication you may be taking but it is worth having a look at.

The second way is the one I tend to use and is slightly more complicated but more accurate. It is called the Karvonen formula. Now I was never any good at calculations but even I managed to work this out so I have put an example calculation underneath this paragraph. There are 2 different formulas. One is for anybody who is taking beta blocker medication and one is not. The first calculation is for people who are on beta blockers and the second calculation is for those of you who are not.  You will need to your resting heart rate and probably the calculator on your phone. I promise these are the only calculations I will ever make you do! Once you have completed your calculation you can make a note of it maybe on your phone. You can refer to this when your exercising to make sure you’re exercising safely. Good luck with the calculation!

Target heart for somebody taking Beta blockers


We have a 65 year old, on beta blockers with a resting heart rate of 75.

220–65 (age) – 75 (resting heart rate) –30 (beta blockers)= 50

40% target heart rate:  0.4 x 50 = 20 + 75 (resting heart rate) = 95 bpm

70% target heart rate: 0.7 x 50 = 35 + 75 (resting heart rate) = 110 bpm

The target heart rate is 95-110 bpm for this person. That’s how you do the formula if you are on beta blockers.


Target heart rate for somebody not taking beta blockers


We have a 65 year old, not on beta blockers with a resting heart rate of 75.

220 – 65 (age) – 75 (resting heart rate) = 80

40%: 0.4 x 80 = 32 + 75 (resting heart rate) = 107 bpm

70% 0.7 x 80 = 56 + 75 (resting heart rate) = 131 bpm

Target heart rate is 107 – 131 bpm.