Relationship between diet, Bp, cholesterol and circulatory disease

How we live our life in respect to what we eat, drink, exercise and smoke depicts how our bodies deal with it. It is widely known that physical activity serves as a regulator to assist with weight management, high blood pressure and stress. Regular physical activity even on a moderate level produces a balance within the body between exertion and relaxation that is important for the body's equilibrium. Lifestyle and cardiovascular disease have been constantly linked through poor diet, smoking, being overweight, drinking to much and being inactive.



Being overweight together with poor diet which is high in salt and saturated fat causes high blood cholesterol. Cholesterol is one of the main components of the fatty deposits that produce atheromas. Atheromas is where damage has occured to the artery by fibrous plaque which partially blocks the lumen of the artery. This happens when white blood cells and lipids start clumping together under the lining in the artery to form fatty streaks which gives increased blood pressure due to the restrictive blood flow from the artery.



Atheromas also increase the risk of:

• Anerysm - which is where the increased level of blood flowing through the weakened artery pushes through the outer elastic layer to produce a balloon like swelling, which is prone to burst and haemorrhage.


• Thrombosis - is a blood clot that is caused by the atheroma rupturing through the inner lining of the artery (endothelium) which leaves a rough surface within the artery wall. Platelets and fibrin accumulate around the site of the damage to form a thrombus (blood clot) that can completely block the artery or move to block a blood vessel eleswhere in the body. The main danger of this is if the clot blocks an artery that supplies blood to the brain causing a stroke, which is where the tissue within the brain gets damaged due to lack of oxygen.


• Angina - is where you feel severe chest pain due to the lack of oxygen to the heart due to the coronary arteries becoming narrowed due to atheromas.

Peripheral vascular disease is another inherent sympton of poor lifestyle choices. It covers a group of problems that is associated with poor circulation to the feet and legs caused by a progressive blocking of the arteries in the leg. Diabetics are more likely to develop poor circulation to the foot however other risk factors are smokers and the physical inactive which are all contributors to high blood pressure and high cholesterol. The biggest problem associated with poor circulation is the development of sores and infections that can develop on the foot which cannot heal as well as they should due to the lack of oxygen to the body tissues essential for healing.

Lifestyle really does play a major part in keeping us healthy, however it doesn't have to be boring. I find the best way is to follow the 90/10 balance. 90 percent of the time you are active, eat healthy and drink in moderation however there are times when it is okay to have a little of what you fancy and do nothing. So as I referred to in the beginning of this blog creating this balance between exertion and relaxation is paramount to the body's equilibrium essential for sustaining of life.

Evaluation of the effects of smoking on the body systems

Smoking has long been associated with the cause of lung cancer as tobacco is made up of cancer producing chemicals like carcinogens. However tobacco smoke also contributes to a number of other cancers which has a detrimental effect on the heart and the rest of the body. Lets face it if you keep putting a mixture of nicotine and carbon monoxide present in each cigarette (which will clog the lungs up like soot in a chimney) this is going to put tremendous strain on the heart and the blood vessels.

The costant inhalation of carbon monoxide will rob your brain, heart and muscles of much needed oxygen. This will cause the heart to work harder causing your airways to swell up and get blocked as smoking causes fatty deposits which narrow the blood vessels ultimately allowing less air into the lungs. This can cause not only heart attacks but strokes due to the strain being put on the heart.

Emphysema is an illness which is synonymous with smoking as it slowly rots your lungs. This is caused by the constant coughing that develops due to the sticky constituency of tar which stops the cilia on the mucucous membrane moving allowing a build up of mucus. This constant coughing damages the aveoli making breathing very difficult, allowing the lungs vunerable in contracting bronchitis and pneumonia.

The good news is that no matter what age or how many cigarettes one smokes, the health benefits of quitting is very quick. From the moment you quit your blood pressure and pulse rate return to normal and the carbon monoxide is being elimated from your body as your lungs are able to breath normally so improving circulation.

The changes in artery structure associated with circulatory disease

We can compare blood travelling through arteries to that of water being pumped through a hosepipe. Turn the tap up on the hosepipe and the pressure of the water coming out of the hose is greater, turn it down and so does the pressure. So if we liken that to the pressure of our blood in the arteries, if the blood flow is constant without any constrictions then a normal blood pressure reading is obtained. However if the arteries are blocked or if there is some kind of build up within the artery then the pressure must go up to force the blood around to the viatal organs.

The build up of fat or plaque is the main factor in high blood pressure and heart disease. With this build up of fat and plaque the whole structure of the artery changes. It goes from a very efficient system that is both strong and elastic to a system that has been narrowed and hardened making it more difficult for blood to flow through around the body. The main consequence of this is inadequate blood supply, tissue damage occurs, increased risk in a blood clot forming and worst case senario death. As you can expect with poor circulation oxygen rich blood has difficulty in reaching the heart, which can cause angina or a heart attack

Redistributing of blood during exercise

As we start to exercise our muscles require more energy, therefore we need more food and increased oxygen to produce this. This extra oxygen must be made available to our blood through increased breathing and depth of breathing to obtain this. Our blood cells also need to react to this extra oxygen as they need to deliver more oxygenated blood to the working muscles. When the ATP gets used up within the muscles, then the muslce starts to produce several metabolic byproducts in the biochemical process of energy transfer, ie. carbon dioxide, adenosine. When these byproducts leave the cells within the muscles this then enables the capillaries which have been previously closed to dilate. Along with the dilated arteries, this increased blood flow transports the oxygenated blood required to the working muscle.

There is also a bit of division going on as the blood flow is redistributed less to all other major organs apart from the brain and the heart where more blood flows to the working muscles. This is down to the sympathetic nervous system which stimulates the nerves to the heart and blood vessels. It is this nervous stimulation which cause the arteries and veins to either contract or constrict, so restricting blood flow to the tissues. So as the rest of the body starts to get the message to constrict the blood vessels and the muscles dilate their blood vessels. The blood flow from the say the stomach, kidneys etc is diverted to the working muscles.

Mechanisms of Ventilation and pulse rates

In my recent blogs I have explained about the respiratory system, blood and understanding the circulation and structure of blood as well as probably the most important muscle in our body the heart. So what makes all these complexities tick so to speak. How does it all happen and more important what makes our heart beat. It all comes down to one thing, the brain. Actually the cardiovascular part of the brain to be precise. Our brain is responsible for many things, therefore it has many parts to deal with these demands. The cardiovascular part is found within the medulla oblongata, which is located at the bottom of the brainstem. It is within the medulla oblongate that the motor nerves which are responsible for carrying action potentials from the brain to the heart is situated. It is these nerves that are connected to the Sinoatrial Node (SAN) and stimulate the SAN to either speed up or slow down depending on the body's needs.

The response of the medulla depends on the action potentials received by the SAN from baroreceptors. Situated within the aorta they are stimulated when the aorta wall is streched (increase output). So basically the SAN acts as the pacemaker by generating at regular intervals the electrical impulses of the heart beat so maintaining normal cardiac rhythm and pulse rates.

Cardiac Output

In my last blog I described the electical activity which results in a heart beat normally around 70 beats per minute. So how do we get this figure of 70 beats per minute and why is it important. Let us explore more!

Basically cardiac output is the measure of the volume of blood in milliliters per min (mL blood/min) ejected by the heart in one minute to establish the efficiency (or not) of the heart.

• Cardiac Output in mL/min = heart rate (beats/min) X stroke volume (mL/beat)

So if we look at an average persons heart rate at rest of 70 beats per minute, with a resting stroke volume of 70 mL/beat. Then the cardiac output would show:

• 70 (beats/min) X 70 (mL/beat) = 4900 mL/minute.

So why is this important? The heart rate and cardiac output have a direct relationship. As the heart rates increases therefore the cardiac output increases also. Monitoring of cardiac output gives doctors and clinicians the tools to be able to recognize, respond and understand many cardiac emergencies. A general rule of thumb is if a patient has a heart rate that is to fast or to slow then this requires urgent assessment as it could be a result of a blockage of the coronary arteriers which may cause a heart attack (myocardial infarction) or a fatal rhythm disturbance resulting in cardiac arrest.

Also people with heart disease usually have a weak blood supply, thus making their hearts beat slower due to poor electric conductivity. In all cases a electrocardiogram (EKG) is a noninvasive test that measures the electrical activity of the heart. This will detect many heart conditions as a result of high or slow cardiac output being detected in the first instance.

The electric heart

The heart has a natural pacemaker that regulates the rate and pace of the heart. This pacemaker sits on the upper portion of the right atrium and consists of a collection of special electrical cells known as the sinus or sino atrial (SA NODE). The SA node generates electricity which travels across a special pathway to stimulate the muscles of the four chambers of the heart to contract in a specific way.

The heart usually beats about 72 beats per minute on average at rest (normal activity) and is part of an intricate series of events that happen within your heart to produce a heartbeat. Each heartbeat consists of two parts.

• Diastole is where the atria and ventricles relax and fill with blood.



• Atrial is where the atria contracts and pumps blood into the ventricals. The atria relaxes so your ventricles can then contract pumping blood out of the heart.

As mentioned the electrical signal that sets the heart pumping begins with the SA node which then generates the two vena cavae to fill the hearts right atrium with blood from other parts of the body. This signal then spreads right across the cells of the heart to the right and left atria causing the atria to contract. This contraction then produces the action to push the blood through to the open valves from the atria into both the ventricles. The signal arrives at the AV node which sits near to the ventricles slows for an instant which allows the right and left ventricles of the heart to fill with blood. The signal is then released, moves along a pathway called the 'Bundle of His' (which is a collection of heart muscles cells specifically for the conduction of electrical activity which then transmits electical impluses from the AV node to the point of the apex of the fascicular branches) located within the walls of the ventricles.

From the 'Bundle of His' the signal fibers then divide to the right and left bundle branches through the Purkinje fibres which connect directly to the cells within the left and right ventricles. The signal then starts to spread acroos the these cells causing both ventricles to contract, which however doesn't happen at exactly the same time. This is because the left ventricle contracts an instant before the right one does. By doing this it pushes the blood through the pulmonary valve situated at the right ventricle to the lungs, then through the aortic valve for the left ventricle to the rest of the body.

As the signal passes the walls of the ventricles relax and await the next coming signal so the whole process continues over and over again.