Circulation 101

A lot of news stories have been coming out lately speaking to the health complications that can arise from having a lifestyle that doesn’t involve a lot of movement.  Working in an office environment, commuting, working at a computer, playing video games, watching TV – many of the modern activities that people engage in, especially in America, just don’t involve as much movement as the generations proceeding this one.  For example, thirty years ago, if a person worked in an office, he or she would often have to get up several times during the day to take paperwork to another department, use the file cabinets, and talk to fellow employees, for just a few examples.  Today, many of those tasks have been eliminated by the widespread adoption of computers, extended inter-office phone networks, cell phones, and policies designed to keep people at a desk as much as possible.  In some offices, time away from one’s desk is actually grounds for punishment.  This had led to many people being far more sedentary than their ancestors and as a result, many unexpected health issues have arisen because of it.  The purpose of this article is to look at one aspect of how the body works and to explore both how today’s world affects it in a negative way and some simple things that can be done to alleviate and even reverse the problem.  Ladies and gentleman, let’s talk about the circulatory system.

Introducing the Players

Before the negative effects of the modern lifestyle on the circulatory system can be addressed, first some time needs to be spent looking at the parts involved and how they work.  The circulatory system, for the purposes of this article, involves the parts of the body dedicated to moving blood throughout the various organs and tissues of the body for the purpose of maintaining life and health.  The heart, of course, is the main organ of the circulatory system, but there are also the ‘pipes’ which are required to actually get the blood to where it needs to be.  The arteries, veins, and capillaries are just as important as the heart when it comes to nourishing the various parts of the body.  The skeletal and smooth muscles of the body also play an important role in moving blood to where it needs to be.  Finally, the nervous system, which doesn’t actually have a part to play in actively moving the blood, plays a very large role in determining exactly how hard the circulation works and can affect elements of circulation from blood pressure to heart rate to consciousness.

Before the examination of the parts begins, however, first the blood itself should be talked about.  To anyone who has watched a vampire movie and heard the phrase “blood is life”, it should be noted that this isn’t an exaggeration.  When the flow of blood is disrupted to an area of the body, serious health issues can arise fairly quickly.  Frostbite is an excellent example of this.  When a body part is exposed to extreme cold, circulation in that part of the body diminishes rapidly. Within a short amount of time, tissue death and necrosis occurs.  If blood flow can be restored quickly, that body part can be saved, but if not, then that part must be amputated to keep the resulting infection from killing the individual.  The reason this happens so quickly is because of multiple factors – the blood carries essential nutrients that are needed to keep the cells functioning, oxygen which is also essential to the maintenance of tissue health, and immunological factors which fight the bacteria which are continually growing in and on the body.  Blood also carries waste products away from tissues, waste products which, if left in place, can cause complications ranging from gout (where uric acid crystals gather to such a degree that they interfere with the movement of joints) to cancerous cell growth (due to the presence of toxins causing cell mutations).  Finally, blood is also needed to maintain a stable body temperature. As mammals, humans need the body to remain within a relatively narrow temperature range to ensure health.  If the body gets too hot or too cold, cellular processes and tissues are negatively affected and can become permanently damaged.  The brain is an excellent example of this because of its extreme sensitivity to heat.  If the brain is exposed to temperatures over 104° for even a short time, permanent damage can occur.

The blood also carries cholesterol which, even though it has been demonized in recent years, has a very important function in maintaining the health of the circulatory system.  When arteries, veins, and capillaries become damaged, cholesterol acts like an internal patching kit, helping protect the body from ruptures which could lead to internal bleeding.  If the amount of cholesterol is too high however, this can create blockages which can then raise blood pressure or even completely obstruct blood flow to necessary systems in the body.  So even though high cholesterol rates are a danger to health, it is worth noting that this substance does provide a very important role in the body.

A final note about the blood is that it must be kept in a relatively narrow ph range.  Human blood is normally slightly alkaline, but certain things can increase the acidity of the blood.  Some of the most common elements that increase blood acidity are sugars and carbon monoxide.  This increased acidity damages the tissues inside the arteries, veins, and capillaries, making them more rigid.  The added rigidity makes them more vulnerable to rupture and increases the pressure inside them, raising blood pressure throughout the body. Sugars are most commonly added dietarily and the most common causes of carbon monoxide are cigarettes, car exhaust, and industrial air pollutants.

The heart is the main organ and most obviously necessary part of the circulatory system.  It is the pump that pushes blood throughout all of the tissues of the body and is essential to maintaining proper health.  After having said that, it should be noted that most animals can exist for an extended period of time without a functioning heart as long as there is something else maintaining the movement of blood through the body.  This is how CPR and life support can maintain life in someone who has had his or her heart stop or whose heart is no longer able to supply blood adequately to the body.  The problem with relying on such measures is that the heart, through its connection to the brain and the nervous system, is continually adjusting both the rate and the force at which it pumps.  Most artificial means of maintaining a proper heartbeat  (including implanted pacemakers) just don’t have the flexibility or the means to consistently adjust these factors to the same degree as the original.  In the cases of mechanical replacements, such as in life support, there are also increased dangers of infection, as the closed circulatory system humans are born with is much better at keeping blood-born infections from spreading too quickly through the body.

In terms of anatomy, the heart is actually a complicated piece of equipment by design, but it’s rather simple in its make-up.  Essentially, the heart is made up of muscle tissue and nerve fibers.  It has four chambers that contract in sequence, working in a manner similar to a vacuum pump.  As blood is pushed out of one chamber, the negative force pulls more blood into it.  The nerve cells in each chamber combined with information coming from the brain then tell the heart when to start the next sequence of contractions.  These contractions are regulated by an internal pacemaker which keeps everything firing smoothly, in theory.  In reality, however, the heart rate is extremely variable.  The heart rate will increase naturally when greater demands are placed on the body, so engaging in physical exertion, being under stress (mental or physical as well as real or perceived), and suffering an injury will all cause the heart rate to increase in order to get more blood to tissues in order to keep up with the faster consumption of nutrients.  Also, if the blood itself isn’t carrying enough nutrition, such as in anemia, oxygen deprivation, or following massive blood loss, the heart rate will increase in order to make up for the lack of nutrients by volume in the blood.  In a healthy subject, once these times of stress are over, the heart rate should return to normal after the stress has passed.  The less healthy or more depleted the person is, however, the more the heart has to work to return the body to homeostasis.

This is an important point, because as stated above, the heart is first and foremost a muscle, so the harder it works, the stronger it gets.  This is not necessarily a good thing.  A heart that has become too over-muscled will start to lose tissue flexibility, so that the chances of some of the tissues becoming damaged during the next bout of exertion become higher and higher.  This is why the heart attack rates always rise during the colder months.  To use the example of the person who has a cardiac episode while shoveling snow, it is a case where greater exertion combined with a greater amount of blood flow needed to maintain body temperature causes the heart to seize up.  The heart muscles then become damaged, much like a pulled muscle in the arm or leg, but because of the importance of the tissue, it is much more debilitating.  Likewise, where as scar tissue that forms from this type of damage may only have a minimal impact on an extremity, that same scar tissue will make the heart function far more poorly.

One of the ways that the work of the heart is eased is through movement.  Every time a skeletal muscle is moved, the contraction of the muscle help push any blood that is in or near it further through the circulatory system.  This is of vital importance in the extremities where the distance of the tissues being nourished is at the furthest distance from the heart.  As such, the amount of force needed by the heart to move this blood is much higher than what is needed to nourish the systems in the torso.  The greater density of muscle tissue also requires more force to move blood through it (and if the muscles are tight, even more is required).  By making use of the skeletal muscles, the body is able to reduce the force required by heart in order to get blood to and from the extremities.  When it comes to the circulation of blood in the legs, this function is even more important as gravity must be overcome as well.  Heavier waste elements are more likely to settle in the feet and lower legs and if a person spends a greater amount of time with his or her legs in a static position, then the amount of both blood and waste products will begin to pool there.  While standing can help alleviate this by involving the postural muscles, actually being able to lift the legs and move them on a regular basis has a much greater benefit.  Even walking a short distance every once in a while can reduce the amount of settling the blood is able to do in the legs.  This is why being in a seated position for extended period of time is so dangerous over the long term.  The increased strain on the heart may be hidden by the lack of exertion, but the heart is still having to work that much harder to overcome inertia. Even lying down is preferable, because it removes much of the effect of gravity (though extended periods of being in that position is harmful in different ways, but that is more a case of days rather than hours).

So now that how the blood is moved through the body has been examined, it is time to talk about the actual paths that it takes to get there.  There are three main structures that the body uses to transport blood from the heart to where it needs to be and back again: arteries, veins, and capillaries.  Each of these works in different ways and each one has its own unique features.

Arteries are used to transport blood away from the heart.  These tend to be some of the biggest pathways in the body and if ruptured or damaged, can cause a person to loose a significant portion of blood very quickly.  There are several reasons why they function in this way.  Arterial walls are lined with smooth muscle that helps move blood through them and also helps exert additional pressure to get that blood back to the heart.  The smooth muscle lining also helps protect the arteries from the greater pressure being placed on them by the heart.  The blood in the arteries tends to be more nutrient rich, which makes the blood in them more essential to healthy body function.  As a result, arteries tend to be deeper in the body, which makes them more vulnerable to obstruction by tight muscles.  For example, people who have chronically tight calves also tend to get cold feet.  Part of the reason for this is because fresh blood isn’t getting through to the feet as well as it is to the hands.  In today’s world, due to the increased use of the hands for everything from using a mouse to playing video games, tight forearms are becoming as common as tight calves, so colder hands for that same reason are becoming a more regularly seen complaint.

Veins, in comparison, are much simpler. Because the blood they carry is usually full of metabolic waste products, the body considers the blood inside it to be of less value, so there is less incentive in getting it back to the heart as quickly as possible.  Veins tend to be closer to the surface of the skin and their walls are much thinner, lacking the smooth muscle lining (one of the reasons why blood is usually drawn from them as opposed to arteries).  They do have one unique feature, however.  At various points throughout the course of the vein, there are small one-way gates that allow the blood to move closer to the heart but keep it from flowing back towards where it came from.  These gates are very vulnerable to pressure however, and in cases where the blood is not moving back towards the heart effectively, will collapse and blood will begin to pool.  A common example of this is spider veins, which are points where blood has pooled in a vein to the point at which they can be seen through the skin and are often very uncomfortable.

Finally, capillaries are very small blood vessels which are the site for the transference of blood to tissues from the arteries and then back to the veins.  These tiny vessels are everywhere in the body, but are also some of the body’s most vulnerable tissues.  Like a stream or tributary, even a small blockage can keep them from flowing properly.  Usually the blood pressure these tissues are exposed needs to be kept relatively low, as these tissues are very easy to rupture.  The capillaries in the eye are extremely vulnerable to this, as even a sneeze can cause a rupture that, while disturbing in appearance, is a relatively common occurrence.  Of far more danger to the capillaries are exposure to high levels of blood acidity combined with increased pressure.  This is a common situation in diabetics and can cause blindness if not closely regulated.  The capillaries at the extremities are also very vulnerable, particularly in the feet, and in individuals in poor health, this will often be the first site of problems, including chronic numbness, tissue death, and infection.

How It All Fits Together

Now that the individual ingredients have been introduced, here is a very simple example of how blood moves through the body and how the things that have been mentioned play a part.  Blood is in constant motion throughout the body, so while this example may help give some insight to how it works, be aware that this is not an exact reflection of what is happening in the body, but instead a caricature that greatly simplifies things for illustrative purposes.

Starting on the right side of the heart, blood that lacks oxygen is pushed through the two chambers of the heart to the lungs.  Here oxygen levels are replenished in red blood cells and it is returned to the left side of the heart. From the left side of the heart, blood is pushed into the arteries and is distributed throughout the body. If it is going to an organ in the torso, it’s journey is relatively short, and it returns after nourishing the organ tissues via the capillaries.

For the blood bound to the extremities, including the head, the journey is much longer.  The liver is usually within four to six inches of the heart, the kidneys about the same.  Compare that to the lower legs, which can be several feet from the heart.  While the pressure from the heart and arteries can easily push the fresh blood down to the these tissues, the effort required to push that blood back up to the heart, plus all the blood that was there previously, is much greater.  After moving from the arteries to the capillaries and then back to the veins, the return journey begins.  As the blood moves gradually up towards the heart, each push moves it to the next venous chamber, where the gates previously mentioned keep it from flowing back to the tissues it was in previously.  If a person is moving while this is going on, the muscle contractions also aid in the movement of the blood back towards the heart.  Eventually, the blood will move back up into the torso where, after passing through organs such as the liver and the kidneys to remove waste elements from the blood, it finally returns to the heart to start the journey over again.

What Could Possibly Go Wrong

It two words, a lot. As mentioned before, the capillaries are extremely fragile, partly because of their size. In some places, they are so narrow that only a few blood cells can pass through at a time.  Think of a turnstile in a subway, where if everyone is passing through at an orderly pace, there are no problems, but as soon as the pressure becomes to high and people start trying to jostle ahead, gridlock results.  One of the wonderful things about the body is that there are redundancies on top of redundancies.  This means that if one capillary is temporarily clogged, there are still other routes for the blood to get where is needed.  The problem comes about when too many capillaries become blocked over an extended period of time.  As tissues start to starve to death, functions in the body become less effective and the body’s ability to repair damage becomes less able to deal with the situation.  Over time, this can cause a cascade failure that eventual leads to the necessity of medical intervention, but even that might be too little too late.  The kidneys are a prime example of this.  In cases of chronic high blood pressure or diabetes, the capillaries in the kidneys start becoming damaged and die off.  This keeps the kidneys from being able to effectively remove toxic elements from the body while at the same time increasing the need for that to happen.  (Both diseases used in the example are ones that are eased by urination.  In high blood pressure, reducing the amount of fluid in the body reduces the pressure, while in diabetes, urination is used to lower the level of sugar in the blood).  Over time, the strain on the kidneys can cause them to shut down, leaving the individual in need of a transplant or mechanical intervention via dialysis.

Cholesterol was also mentioned above as something that gets blamed for a lot of issues involving circulation and heart health.  In an individual with low to normal cholesterol and blood pressure, cholesterol can act to reinforce damaged circulatory systems, but if the amount present or blood pressure is too high, then the amount in the body will actually start raising blood pressure as the pathways become choked with the patching material as well as increasing the risk of a chunk of it breaking off and interfering with the function of another organ such as the heart, brain, or lungs.  There is a similar risk with blood clots, which can form in the blood stream as a result of trauma. In normal circumstances, the body can dissolve the clot over time, but if the blood pressure is too high, it can dislodge a clot, causing it to obstruct blood flow to vital body systems, leading to permanent impairment or death.  The lungs and brain are particularly vulnerable to clots affecting them this way.

Speaking of the brain, in order for blood to nourish it, it must first pass though the neck.  Unfortunately, the neck tends to be a center of tension for just about everyone. This tension in the muscles narrows the available space for the blood to pass through, lowering the amount that reaches the brain.  Nerves in the brain which monitor blood pressure and the nutrients reaching it react to this low blood flow by telling the heart to increase its workload, thus raising blood pressure.  However, since the brain is connected to the same circulatory system as the rest of the body, increasing the blood flow to it increases the blood pressure to the entire body, increasing the problems that may be occurring elsewhere.

Another factor that can negatively affect the circulatory system is obesity, for a variety of reasons.  The more weight a person carries means that a certain amount of muscle must be added to support that weight.  This added muscle tissue, as well as the added fat, requires more blood to maintain it.  This means that the heart must do more work in order to keep the rest of the bodily systems nourished.  If the diet is high in fat during this time, the heart will actually take some of that fat from the blood stream to add its own structure, storing it away to turn into energy.  This added mass will negatively affect the heart much like added muscle tissue would, leaving the heart more vulnerable to heart attacks and other cardiac conditions.

A final element that can add unwanted stress to the circulatory system is malnourishment.  In Chinese Medicine, the hair and nails are created by an excess of blood.  To put it another way, it can be thought of as such – there cannot be an excess if the needs of the tissues proceeding them are not being adequately met.  This means that dry, brittle hair and nails can be a good indicator of insufficiencies in the circulation, either because the blood cannot the extremities or because that blood is insufficiently nourishing.  Nourishment, in this case, meaning not just nutrients like proteins, carbohydrates, and minerals, but also gasses such as oxygen.  In an environment where even a few of these things are lacking, more blood must be pushed through, which means that the blood pressure is increased, which ultimately means more strain on the heart and other circulatory systems.

What Can Be Done

There are several ways for an individual to halt or even reverse damage done to the circulatory system by the modern world.  Most of these changes involve at least some alteration to lifestyle but most of them will not require major changes to day to day life.  The first and most important thing is to move.  Just standing up and walking from one side of the room to the other every fifteen to thirty minutes can have a cumulative positive impact on the whole body.  Those worried that this may be too distracting from their work day should know that every time a person checks his or her email, he or she will often lose twenty to thirty seconds just in adjusting to the distraction.  In a busy environment, moving while thinking of a response will give an individual plenty of opportunities to engage in at least a little walking around.

Adding regular aerobic exercise can be even more beneficial.  Something as low impact as walking for thirty to forty-five minutes a day can have multiple benefits.  As mentioned, the movement of the legs and arms will increase the blood flow to and from the extremities. Aerobic exercise will also give the added benefit of making the heart and lungs more efficient, so that the times when the person is at rest or forced to remain in one position for extended periods will do less harm than they would in someone who was not actively exercising.  Gentle exercise will also help the muscles to be looser and less likely to seize up, which will also make it easier for blood to move through and past them.

Speaking of muscles, stretching on a regular basis, especially stretching the neck, can offer a lot of aid in keeping tension from blocking the normal flow of blood and have a cumulative effect in lowering blood pressure.  A recent article showed that yoga and stretching are equally effective in contributing to overall health, but yoga has two major benefits over a less organized stretching practice. One is that most yoga routines engage every part of the body, so that no major muscles groups are missed. The femoral artery travels through the groin at the point where the leg connects to the hip. This is also a place where people hold large amounts of muscular tension.  One of the best ways to stretch this is through a deep lunge.  Many personal stretching routines neglect this part of the body.  In contrast, most yoga routines incorporate several variations of the ‘warrior’ pose, which is wonderful for targeting tight hips.

The second benefit of yoga over a less whole body approach to stretching is the importance placed on breathing.  Many people who learned most of their stretches as part of athletics when they are younger think the goal of a good stretch is to go as far as possible, and will hold their breath when they do so.  This actually increases the pressure on the joints and muscles and increases the chance of injury.  When a stretch moves past the point where steady and slow breathing is possible, this is actually the body telling the individual to back off a little.  Holding the breath is a stress response, and when a person pushes past the point where they begin holding their breath, the chances of straining muscles, tendons, and joints increases.  An education in yoga often includes strong and repeated reminders on the importance of breathing, and even if the yoga practice is eventually dropped, the lessons imparted can still be of value when applied to other stretches.

One of the other benefits of maintaing calm and deep breathing during either exercises or stretching is that it floods the body with oxygen.  Oxygen, in addition to being an essential nutrient for almost every aspect of the body, also makes the blood less acidic. This will help keep the tissues of the circulatory system more flexible and better able to respond to demands placed on it by the individual.  This benefit isn’t limited to activities involving movement.  Engaging in a meditative practice with a strong breathing component, or even becoming more aware of breathing can allow for at least some of the benefits greater oxygen intake affords.  As an added benefit, exercise, stretching, and meditation can all lower stress that a person feels throughout the day. This reduction in stress will ease the demands on the system as well as giving benefits including less fatigue, greater energy, and a more positive mindset.

Nutrition also plays a major role in maintaining a healthy circulatory system.   Foods that are rich in sugars and preservatives can harm the tissues of the circulatory system by altering the blood ph as well as adding fat to the body, which adds further strain.  A diet heavy in meats, especially cured meats, will also make the blood more acidic, further straining the circulation.  Excessive salt intake can also be very damaging.  Some of this damage can be mediated by increasing water intake so that the concentration of these materials in the blood is lowered.  Conversely, being dehydrated will make the concentrations higher, increase the damage they can do to tissues they come in contact with.

Increasing green vegetable intake is probably one of the best ways to reverse these problems.  Green leafy veggies tend to contain a lot of water, aiding with hydration, as well as containing elements that increase alkalization, making the blood less acidic. They also contain a lot of fiber, which bonds to harmful elements in the blood stream and makes it easier for the body to flush toxins.  Increasing fiber intake through other foods will also offer similar benefits in terms of cleaning damaging elements from the blood stream.  The best diet is, as always, a well-balanced one with an emphasis on freshly made foods where there is a strong focus on fruits and vegetables and avoiding processed and pre-made entrees.

In Conclusion

Hopefully this information has been valuable to people who wanted to learn more about how their body functions.  The cardiovascular system is simultaneously simple and extraordinarily complex, so as long as this was, really it’s just scratching the surface.  However, considering how absolutely invaluable it is for life and how many chronic diseases involve it, even the glimpse offered by this entry will be helpful for those seeking a little more understanding of how it all fits together.