Explaining the Mystery of the South East Stroke Belt

(First time published on 2006 – Last time edited on 6 0f December 2013)

Contents

1) Foreword

2) Introduction

3) Physical Geography and Stroke Incidences

4) The Reasons for the Lower Incidence of Stroke in South Florida

5) The Reasons for the Higher Incidence of Stroke in North Florida than in South   …. Florida

6) The Reasons for the Lower Incidence of Stroke in the New York Metropolitan ….Area

7) The Reasons for the Racial Disparity in Stroke Incidence

8) Susceptibility to Stroke when Migrated to Geographical Regions with Lower   ….Incidence of Stroke

9) Summary

1) Foreword

Everywhere in the world people are afraid from stroke and the majority of them are afraid even just thinking about stroke. Living in certain geographical areas where it is known that on average strokes occur more often than in other areas is an extra burden.

Understanding why in some geographical areas incidences of stroke are more common than in others will open the way to understanding the real cause of stroke and will enable us to design an effective and efficient treatment for stroke survivors.

Knowing the factors which make us more prone to stroke will offer an explanation of how to make us more resistant, or at least less vulnerable, to stroke.

I am sure that everyone will be able to do something about the prevention of stroke without changing the place of residency.

I hope this article will not only bring a positive attitude to everyone but it will also give us knowledge towards preventing stroke, it doesn’t matter if he/she is a stroke survivor or he/she lives in a particular geographical area.

2) Introduction

It has been known for about fifty years that the incidences of stroke are more common in the South Eastern States of the USA, an area known as the “Stroke Belt”. In the “Stroke Belt” area the incidences of ischemic and hemorrhagic strokes (and an increased risk of death from stroke) are substantially higher than in the rest of the USA. (Even children in Stroke Belt states have an increased risk of death from stroke compared with children in other states to an extent similar to adults).

The “Stroke Belt” is usually defined as an 11 state region which includes; Virginia, North Carolina, South Carolina, Georgia, Alabama, Mississippi, Louisiana, Arkansas, Tennessee, Kentucky and Indiana. Incidences of stroke in these states is 50% higher than in the West and in the Northeast of the US, 30% higher than in the Midwest of the US and nearly twice higher than in the New York metropolitan area. By taking a closer look at the available data we can see that not only is the “Mystery of the Southeast Stroke Belt” a reality but the “Mystery of the Midwest Stroke” is also a reality, because for unknown reasons, the Midwest of the country has a higher incidence of strokes than the West and Northeast of the country.

By comparing the incidences of stroke between the West and the Northeast of the country with the New York metropolitan area, we can see that the incidences of stroke is much higher in the West and Northeast than it is in the New York metropolitan area and because of this fact, we can call it the “Mystery of the Northeast Stroke” and the “Mystery of the West Stroke”.

Actually, any incident of stroke, it doesn’t matter if it is in the Southeast or in the Northeast of the country or anywhere in the world, is a mystery because till this day, no one knows why some people are affected by stroke and others are not.

3) Physical Geography and Stroke Incidences

By comparing the incidences of stroke between different regions we can see that the geographical factors play an important role in the incidences of stroke. This leads to the conclusion that by understanding why incidences of stroke are more common in some regions than in others, this will enable us to make the first step in attempting to understand the real cause of stroke anywhere in the world.

If we take a look at the map of the area where the Stroke Belt States are located, we can see that a significant part of their territory consists of flat surfaces of the ground (plain area). This points out that the people who live in hilly areas and in mountainous areas are less prone to strokes compared to the population that lives in a flat (plain) area.

One more contributing fact that leads to this conclusion is that this stroke belt has a “buckle” (a zone within a zone) where stroke death rates are “substantially higher” than in the stroke belt itself, and twice as high as the rest of the country.

Reporting in the May issue (1997) of the American Heart Association journal “Stroke”, scientists identify the “buckle” as the coastal plain sectors of North Carolina, South Carolina and Georgia. In this 153-county area, the new study shows that stroke deaths are 2.1 times higher than the rate of the nation’s average among people whose ages are 35 to 54, and 1.7 times greater for people between the ages of 55 and 74.

Taking a look at the geographical map of this region it is visible that the coastal plain sectors of North Carolina, South Carolina and Georgia is completely flat and as it is more distanced from the coast, the area is less flat (piedmont). This shows that the population living in coastal plain areas in those three states are more prone to stroke than people who live in the piedmont and mountainous regions in the same state.

We can see that somehow physical geographical factors are responsible for the increased and decreased incidences of stroke in a particularly geographical area (coastal flat areas, piedmont and mountainous areas) inside the Stroke Belt area.

The question why and how geographical-environmental factor is to some extent responsible for the incidence of stroke will be easily answered by a short introduction about locomotion and muscle activity.

  1. Any human locomotion is at the same time a motor skill activity.
  2. A diversity of motions means a diversity of neuromuscular system activity.
  3. The diversity of physical activities is at the same time a diversity of neuromuscular control centre activities.

The maintenance or improvement of the physical skills ability means at the same time the maintenance or improvement of the neuromuscular control centre.

We are performing locomotion like walking, running and as well as the voluntary and involuntary movement of the limbs by the voluntary and involuntary activities of the muscles.

The activity of the muscles is in a causal relation with the neuromuscular control centre activity and neuromuscular peripheral system activity.

Every conscious physical activity consists of the mental activity, neuronal activity and the musculoskeletal system activity.

The question why and how geographical-environmental factors are to some extent responsible for the incidences of stroke will be answered by comparing the everyday locomotion done in flat areas to the everyday locomotion done in a hilly (piedmont) and a mountainous area.

People who live in areas with hills and mountains are more frequently forced to incorporate a diversity of motion in their everyday locomotion because they are more often confronted with activities like walking up a hill, walking down a hill and walking diagonally up and down a hill etc.

On the other side, the people who live in a flat-plain area do not often have the opportunity to walk down or up a hill, most of their lives they walk only on flat surfaces.

Walking on a flat surface for most of the time has the consequence that the habitual gait is used to perform everyday locomotion (habitual walking and running pattern) to a greater extent than by people who live in a hilly and mountainous area.

The people who live in hills and mountainous areas, are in general more often obligated to incorporate diverse physical skills in their everyday locomotion. In general, they will more often exercise their motor skills compared to the people living in flat areas.

By exercising our own motor skill we are at the same time exercising our own neuromuscular control centre. (It can be said that by exercising-using our own motor skill ability we are exercising-using our own neuromuscular control centre).

The physical geography of mountainous area obligates us to use a diversity of physical skills (slowing and speeding skills, jumping skill etc.) in order to perform everyday locomotion.

A diversity of physical activities is at the same time a diversity of neuromuscular control centre activity.

Concerning the neuromuscular control system, the physical geography of hilly and mountainous region forces an increased activity of the neuromuscular control centre and on the other side; it forces an increased diversity of the neuromuscular control centre activity while performing everyday locomotion.

Habitual locomotion for a prolonged period of time has the consequence that the musculoskeletal system and neuromuscular peripheral system is physically active, but the neuromuscular control centre is under-active.

A prolonged period of inactivity or insufficient activity of the neuromuscular control centre leads to its deterioration.

  1. By a prolonged period of doing physical activities mainly in a habitual way, the motor skill deteriorates.
  2. A deterioration of motor skill ability means at the same time a deterioration of the neuromuscular system.

On a side note: the geographical environment of hilly and mountainous areas obligates us to do locomotion in such a way that our mind is in the present. For example, when we are walking down the hill we have to take care not to fall down. And all the time by doing this activity our mind is in the present. Also, we can’t walk down the hill with habitual walking patterns. On the other side, unexpected obstacles on our way by walking or running are factors that obligate us to increase awareness and diversify our motions.

Apart from that everyday locomotion in a hilly and a mountainous area forces an increased diversity of motion and activity of the neuromuscular control centre; it has a calming effect on the mind. It is an excellent guardian against stress because as we are mentally involved in physical activities (the entire brain is involved in physical activity) there is no space left for the stress.

Analysing and comparing the biomechanics when walking on an even and uneven grounds shows that the daily locomotion performed in a hilly and mountainous area to a greater extent is sufficient to maintain the optimal state of the neuromuscular control centre and that the daily locomotion performed only in a flat (plain) area isn’t sufficient to maintain the neuromuscular control centre to an optimal state.

Differences between the locomotion performed in a mountainous and a hilly area, and the locomotion performed in a flat area explains why the people who live in mountainous regions are less prone to stroke than people who live in a flat area.

5) The Reasons for the Higher Incidences of Strokes in North Florida than in South Florida

According to epidemiological studies, the Northern part of Florida has higher incidences of strokes than in the southern part of Florida.

The incidences of strokes in the northern part of Florida are similar in magnitude to the incidences of stroke in the Stroke Belt States.

The reasons for the higher incidences of strokes in North Florida are; in the southern part of Florida, the great majority of people live in the coastal areas near the beaches, and a reason for this is that the inland of south Florida is mainly a swamp.

In the northern part of Florida, many more people live in the inland area and because of that, people in the north part of Florida have fewer opportunities to walk with bare feet and less opportunity to be engaged in water sports than the people in south Florida.

The physical geography’s effect on the way of life and daily locomotion explains why people in the south part of Florida are less prone to strokes than people who live in the north part of Florida and the people living in the rest of the US, excluding the New York metropolitan area.

6) The Reasons for the Lower Incidences of Strokes in the New York Metropolitan Area

If we take a look at the map of this area, we can see that the entire New York metropolitan area is located on flat surfaces similar as the coastal plain sectors of Georgia, South Carolina and North Carolina where the incidence of strokes is the highest in the US.

The people living in the New York metropolitan area have much less opportunities to walk with bare feet compared to people living in the coastal plain sectors in Georgia, South Carolina and North Carolina, and far less than people living in the northern and southern part of Florida.

All physical geographical factors which contribute towards a lower incidence of strokes in states located on the hills and mountains, like the states in the West, Northeast or those in the Southeast like Florida (Southern part of Florida), in the New York metropolitan area are non-existent.

This all tells us that in the New York metropolitan area, the incidences of strokes should be higher than in the coastal plain sectors of Georgia, South Carolina and North Carolina, but contrary, they are far lower than anywhere in the US.

One important factor which makes the New York metropolitan area different from any other part of the country is that people use the public transport system like nowhere else in the US. Every weekday, four and half million people use the subway alone.

The people who use private cars are most of the time walking with the usual speed (habitual walk). For example, they do not need to hurry to catch their own car, the car always waits for them, it is always at home or in the parking place and they always can afford to walk with their usual speed. (The usual speed is the speed of habitual walk).

People who use public transportation many times come in a situation in which they have to increase their speed of walk with the intention to catch the train or bus, and sometimes they decrease their walking speed below the habitual walking speed, with the intention to avoid waiting long on the station for the train or bus.

By changing the speed of walk, we change the way the neuromuscular control centre works. Each time when we change the speed of walk from usual speed (habitual walking speed) to slow or brisk walk, the activity of the neuromuscular control centre increases.

The next important factor when travelling on the train is the effect of a speeding train (effect of acceleration) and effect of a slowing train (effect of deceleration) on the people inside the train.

For example, if we stand or walk on the floor of the train which moves at a constant speed, we need the same effort to maintain the body in an upright position (upright posture) as we need when we are standing or walking on stabile ground.

The ability to maintain an upright body posture in a still standing position is one physical skill and it is an important part of motor skill.

Explained in simple terms; in a still standing position on the non-moving ground, the sense of balance coordinates the work of the muscles in order to support the body in an upright position.

The sense of balance is a vital component of the neuromuscular control centre.

  1. By still standing on stabile ground and on the floor of the train that moves at a constant speed, the neuromuscular control centre is active to overcome the pull of gravity in order to maintain an upright standing body posture.
  2. But if we are standing or walking in the train at a time when the train increases speed, and at the time when the train decreases speed, the musculoskeletal system increases activity and at the same time the neuromuscular control centre increases activity in order to maintain an upright standing posture (to avoid falling on the floor of the train).
  3. When the body is affected by acceleration or deceleration the neuromuscular control centre has to work against the pull of gravity and at the same time it has to work against the effect of acceleration, or the effect of deceleration, in order to maintain an upright body posture.

Another fact is that the time between speeding and slowing of the train is only a few minutes long, because in the city area, the distance between the stations is short. For example, by travelling in the intercity train, we spend much more time travelling with a constant speed. The time between speeding and slowing in an intercity train is much longer, because of the distance between stations is much bigger. In the case when we are travelling by subway (underground train – tube), we are affected every few minutes by the effects of speeding (effect of acceleration) and every few minutes we are affected by the effects of slowing (effect of deceleration).

We spend most of the time inside the train sitting in the passenger seat, but we still spend plenty of time standing and walking inside a slowing and speeding train. For example, when we are entering a train and before we have the chance to reach the available seat, the train already starts to leave the station, and in this short time we are exposed to the effects of a speeding train, and at the time when the train is slowing down before it stops at the station, many times we have to leave the seat and walk towards the exit door because the time at which the train spends at the station is very short, just enough for some passengers to leave and for some passenger to enter the train. In these situations, the neuromuscular control centre together with the musculoskeletal system is forced to put more effort than usual to maintain an upright body posture; otherwise it will result in a fall on the floor of the train.

Another situation when we are unintentionally exercising our own motor skill is when we are walking in crowded areas, like; an underground station or in the busy street, shopping centres etc. In this case, we are frequently forced to change the speed and direction of the walk to make way through the crowd.

From a psychological point of view, the diversity of motion causes that we are more frequently mentally involved in locomotion. Mental involvement in physical activity is the factor that provides vital stimulations to the central nervous system. A diversity of motion (locomotion) is at the same time a diversity of physical activity. Diversity of physical activity is vital for the musculoskeletal system, as well as being vital for the neuromuscular control centre.

Habitual physical activity doesn’t engage the neuromuscular control centre to a sufficient extent.

By a prolonged period of time of doing habitual physical activities, the neuromuscular control centre deteriorate.

For the time of performing habitual locomotion, the musculoskeletal system is physically active but the neuromuscular control centre is under-active.

The next fact is that the use of public transport has the consequence of spending more time on being on the feet compared to people that mainly use own car for city travel.

One more important fact is that compared to people who use their own car for everyday travel, the person who use mainly city public transport, (subway, public buses etc.) are spending more time in outdoors temperature and that has positive consequences for the periphery and central nervous system.

This leads to the conclusion that in general, compared to the people who live in the rest of the USA, the people who live in the New York metropolitan area are more frequently forced to use a diversity of motion (diverse physical skills) in order to perform every day locomotion and that has the consequence of lower incidents of strokes in the New York metropolitan area than anywhere else in the US.

The man-made environment (city public transport) and man caused environment (crowded place) is responsible for the lower incidences of strokes in the New York Metropolitan area.