Is Shivering the Only Activity on Your Winter Calendar?

While many of our behaviors (or lack thereof) would suggest it, we are non-hibernating animals. Other animals, whose survival depends on it, do hibernate. Such creatures actually go on a necessary eating binge for most of autumn and then, as the frigid weather approaches, they find a suitable spot to remain motionless until nature nudges them with the possibility of finding food. Their stored body fat cautiously doses body cells with fuel.

In as few breaths as possible, these hibernating animals' lungs draw in oxygen. Circulating a minimal blood supply, their heart rates can drop from 80-100 to as low as 10 beats per minute. In the spring, they resume life with surprising strength. Unlike sedentary humans, whose muscles diminish in size and strength (atrophy) if not regularly challenged, these animals' muscle mass remains relatively intact.

We (human beings) are also equipped to withstand a variety of adverse circumstances, and what nature does not provide, we have become resourceful enough to invent or ingest. With unlimited access to food, shelter, clothing, conveniences and advanced technology, perhaps we face a more frightening challenge to our existence - the lack of enough motivation to care. Do you neglect your cells?

It Is Impossible to Conceal Cell Neglect

Although some of us have fooled ourselves into believing it is possible, neither the most advanced medicine nor cosmetics can cover up excessive stress and sleep deprivation, or lubricate to compensate for poor hydration and missing nutrients. Perpetually sedentary cells cannot be mechanically or surgically removed.

A sedentary lifestyle presents a huge risk for the development of many diseases, including type 2 diabetes, the many complications of which stage the exact cellular scenarios for a heart attack or stroke. Yet, we (or our loved ones) continue to take our meds and turn heads away from the facts, and toward computer and television screens.

And while we may not see the devastation of these diseases until symptoms or complications impair/impede some seemingly more important aspect of our lives, you can be sure that dark circles, dry skin, and body bulges pale by comparison. Perhaps there should be a reality television screen installed inside of our bodies so that we could see the consequences of what we do (and don't) do.

News Flash: A little cell respect goes a long way
EXERCISE IS BONAFIED CELL RESPECT
Current research has repeatedly demonstrated, along with healthy lifestyle changes, including appropriate exercise, that many diseases can be delayed, perhaps prevented, and controlled. This month, if shivering is the only activity on your winter calendar, try showing your cells a bit more respect.

Exercise Naturally Lowers Blood Sugar and Reduces Blood Clotting

Type 2 diabetes is a disease in which body cells are unable to effectively respond to the hormone insulin, and other mechanisms necessary to transport glucose (and other nutrients) out of the blood and inside for use as fuel.

Studies have shown that appropriate exercise promotes body cells' sensitivity to insulin, and may potentially compensate for other genetic cellular defects. Additionally, movement has an insulin-like effect. With every muscle contraction, blood sugar is slurped up by cells. Along with proper medical care, including early diagnostic testing, people who may be otherwise predisposed, may never develop, significantly delay, or prevent some of the more serious complications of type 2 diabetes.

Cellular Scenarios - from Type 2 Diabetes to a Heart Attack

Type 2 diabetes typically coexists with and/or promotes increases in blood pressure (blood banging hard on inner walls of blood vessels) and atherosclerosis (growing mounds of gunk lining blood vessel walls). Both scenarios create the potential to catapult a blood clot. Such a clot can suddenly lodge in a small blood vessel leading to heart or brain tissue. When blood flow is blocked, the affected tissue dies, impeding the normal function of the organ - a heart attack or stroke. (Note that your brain and your heart is pretty much YOU.)

Like Hibernation, Blood Clotting is a Survival Mechanism

When tiny blood cells (called platelets) stick together to form a plug, they do so because the blood or a blood vessel has been damaged. While a healthy body is always prepared, and therefore makes and dissolves platelet plugs all day long, some people have a tendency to do more clotting than dissolving. Physical activity moves blood rapidly through the body, resulting in less clotting. With proper medical care, an individual who exercises significantly lowers the risk for the development of both type 2 diabetes and a heart attack or stroke.

For Survival, We Must Pass On More Than Genes

Regular participation in physical activity is as essential to our survival as an animal hibernating in winter. It is a way of life that must be embraced and passed on to our children, students, clients, and patients. Its practice can only be encouraged and fostered by education and example. We pass on a great deal more than genes to our kids. Do you set a good example?

Marla Richmond
Health & Fitness Section Editor
(diabetes.pdf)

The Unique Cells of Your Heart Muscle Tissue

The specialty of the heart muscle tissue is to act as a blood pump. Heart muscle cells contract together, which is what makes the heart an effective blood pump. Electrical signals pass from one heart muscle cell to another quickly, allowing the heart muscle to pump as one unit. The shape of the heart’s electrical wiring system (called the Purkinje system) is a double arc. The heart rate increases or decreases; your heart rate is lower when you are not active.

The branches of a nerve called the vagus nerve, “puts on the brakes” or slows down the heart rate at times when you are not active. Depending on the oxygen and nutrient needs of body cells, blood vessels open and close off blood supply throughout your body depending on needs of tissues. This concept is called selective ischemia.

Your blood and all of its contents must flow smoothly and evenly through blood vessels to and from your heart. Your heart must pump rapidly, and with enough force to get blood quickly to active tissues. However, too much force may result in damage to the inside of blood vessel walls. The loop of blood vessels through which blood travels to and from your heart is basically a closed system.

Although when you cut yourself your blood looks like red fluid, it is really more like tomato-vegetable soup. It is thicker than plain fluid and has a lot floating around in it such as red blood cells, digested food, vitamins, minerals, and oxygen. It takes effort for your heart to push blood into the piping of your blood vessel system. Your heart has to be a strong and effective pump.

All of your body's used blood travels back to your heart through veins. The loop from your heart to your cells, and your cells back to your heart, is what is meant by a closed system. Any activity that makes your heart pump blood out to the large muscles of your body in a repeated rhythm for a period of time (typically ten minutes or more) is called cardiovascular exercise or "cardio." Examples of cardiovascular exercise are walking, running, biking, rowing, swimming, kick-boxing, jumping rope, and dancing. It is important to note that cardio need not be performed all in one session, but in fact, can be accumulated over the course of a busy day.

Over a span of 19 years as a fitness professional and practicing exercise physiologist, one session with two fifth-grade boys reminded me just how much, or how little, (we and) our students understand the human heart and the importance of its care. I will never forget this exchange. It took place about 4 years ago.

Some background—
Eleven-year old David originally consulted me for advice about how to improve his cardiovascular endurance on the basketball court. His best friend, Jake, who was seeking to empower himself and build more confidence, decided that he was going to break a school record for the mile run. About half way through one of our sessions, I asked the boys if they knew anything about their hearts, specifically why we have one. Both boys looked at me puzzled, and as if the answer were obvious. David answered, "What would your blood do if you didn't have a heart?"

David knew a great deal more than I did at his age. Prior to my early thirties, when I returned to school and took coursework in biology, physiology, and exercise physiology as prerequisites to my Masters program in exercise physiology, I never thought about, much less understood, the difference between heart rate and blood pressure, that any of it had to do with oxygen, or that oxygen had anything to do with burning calories.

And honestly, unless one is a practicing medical professional, exercise physiologist, physical/ health educator, or science teacher, few people know much about the topic. Thus, the primary purpose of this section is to answer the same question that I asked David and Jake. "Why do you have a heart?"

While the lessons may appear deceptively simple, the information contained in them is not. However, it is presented in a fun and memorable way, and so the complexity is not intimidating. Perhaps a few of these lessons will spark you and your students into learning more about the heart, and what it takes to keep it healthy.

By the way, Jake did break the fifth-grade record for the one-mile run that year. In four months, he improved his time from a 7:45 to a 6:05 mile. He told me one day, perhaps as an architect, he would build a fitness facility so that other kids could accomplish their goals.

David, now 15 years old, is part of a program called Rising Stars. He is coached by Michael Weinstein, owner and operator of a facility called, Joy of the Game in Deerfield, Illinois.

Below are some creative approaches to teaching students about the heart. They will acquaint students of all ages and knowledge bases with the cardiac cycle and the concept of heart rate. Rhyme is a great way to both understand and remember complicated concepts.

Heart Beats by Marla Richmond, M.S.

Your heart muscle tissue's got a specialty.
Its cells are all connected by electricity.
Your heartbeat begins with a single spark
and this signal's carried through it in a double arc.
If left all its own, your heart would beat in haste,
about 20 beats per minute, a resting heart would waste.
Healthy heart chambers pump your blood much stronger.
Special nerves will slow the beat down, heart relaxes much longer.

The more blood can be pushed in a single beat,
the sooner blood will travel from your heart down to your feet.
Your blood vessels open where it's got to go
and close up on and off where not needed so...
Muscles working hard will get for what they call
with smooth and even pressures on blood vessel walls.
As you'll learn in this lesson, in cycles blood flows
in a closed piping system, here's what you've got to know.

Your blood returns to the heart through the two vena cavae,
fills up the right atrium, your first heart chamber.
From this chamber, it gets pumped to a second one
and then on into your lungs for some oxygen.

In this second right chamber, low pressure is arranged.
Blood enters lung alveoli, where gases are exchanged.
There, oxygen gets pushed through walls of tiny capillaries.
Red blood cells come to pick it up, and back to your heart it's carried.

Still in your lungs, when you exhale, you blow CO2 out.
How fast or slow this all occurs is what breathing's all about.
Your heart's left side is different; refreshed blood travels back.
It goes to the left atrium; that's the top, left sack.

And on from your heart's last chamber,
(the left ventricle) the strongest of them all,
blood is pushed through the aorta with the power of its walls.
It travels through your body, out to its destinations, bringing oxygen and fuel to cells, which go through respiration.

Download a 'word scramble' in Microsoft Word or PDF.

The next lesson is a poem that teaches all about the importance of participation in regular cardiovascular exercise. It also presents the concept of aerobic capacity or VO2 Max. VO2 Max is the maximum quantity of oxygen that can be used by body cells per minute per body weight.

Aerobic Capacity (VO2 max) by Marla Richmond, M.S.

What does respiration mean? It's your cells using fuels
and mixing them with oxygen. It’s really very cool.
Your body uses nutrients and transfers energy
to make a special compound that's known as ATP.

The more you move the more you make; your cells build factories
known as mitochondria, which make your body's currency
to pay for everything you do, from breathing to heartbeat,
and every muscle movement from your head down to your feet.

You know your heart's a muscle? In case your didn't know,
it must beat strong throughout your life; its strength seems not to show.
You cannot pose or "flex" it or pump it up to brag,
but guaranteed, when you challenge it, this muscle will not sag.

It seems we only pay attention to the things we see,
but when you train them, cells will know, they'll make and use more energy.
Your heart will ease its effort, sending blood with fewer beats.
When you exercise your body, the more demands it meets.

Your body builds more branches and blood routes to each cell
so oxygen and nutrients can reach them very well.
The more your cells use oxygen, the more fat you will use,
while running, biking, swimming, or anything you choose.

All in all, what this stuff means, in fancy terms, you see.
Keep moving and you'll improve aerobic capacity.

During cardio, your heart pumps blood in a rhythm that is like a drumbeat in music. Each heartbeat pumps blood out to your muscles. Each muscle movement squeezes the veins inside of them like the grip of your hand milking a cow. This muscle action pumps blood back up to your heart.

The more cardio you do, the better your body will become at the many different cardiovascular activities that you practice. You will increase and improve your aerobic capacity. Improving your aerobic capacity means that you will use oxygen and body fuels better. Your cardiovascular system will change. This means:

	Your cardiovascular system will grow more blood vessel branches. Your blood vessels will get closer to the cells to which they are supplying oxygen and fuel.
	Your heart will become a stronger pump, and will be able to pump out more of its blood with fewer beats.
	Your lungs will be able to take in more air with each breath you take. If you improve your aerobic capacity you will find that you will be much less tired. Even walking through the hallways at school or work, carrying your backpack or briefcase, walking up or down stairs, and playing sports will become easier too.

In my book, The Physiology Storybook: An Owner's Manual for the Human Body, 2nd edition, I drew pictures to illustrate complex concepts. The illustrations make it fun, memorable and accessible. I tried to make the text as concise and clear as possible. It is not "dumbed down," but rather, it is written as if it were a foreign language (which it is) for a non-professional or student.

I write a newsletter for Northwestern University. In it, I approach the science of cardiovascular exercise from a different perspective … looking at it as an oxygen delivery challenge.

Cool Stuff I Learned About the Heart in Graduate School

Why does your heart beat?

Your heart beats in order to pump blood (with the oxygen and everything that it carries) to your body. Your heart muscle is made up of specially designed muscle cells. Your heart muscle tissue is called the myocardium. The myocardium (a group of cells that are considered one unit) is not like ordinary muscle cells such as those in your arms and legs. Arm and leg muscles contract separately when they are told to do so by nerves.

Your heart muscle cells are all electrically connected. If one contracts, they all do, as one unit. This is what makes your heart a good pump. It may be weird to think of your heartbeat as a muscle contraction, but that's exactly what it is. Like a turkey baster that squirts gravy, your heart squirts blood into your blood vessel system. Blood is pushed from your heart out to all of your body parts to supply them with oxygen and other materials they need.

What makes your heart beat faster or slower?

Although your heart's pace is started by your S.A. node, it is slowed down or sped up by messages sent down from your brain through special nerves. These special nerves either "put on the brakes" or "step on the gas." It depends on what your body is doing - sitting still or moving around.

Adrenalin also helps to speed things up when your body's got to move. Your body has many ways of changing your heart rate. Your heart's beat will speed up or slow down to exactly the number of beats your body needs to get your blood to where it needs to go, to do whatever it needs to do. For example, you will typically have a higher heart rate when you are running than when you are walking.

How does your brain control your heartbeat?

Your brain controls your heart's beat through messages sent down through special nerves. Your brain controls many things that happen throughout your body. That is why is it is often called the control center. It has many special headquarters or centers within its tissue. These headquarters or control centers send instructions to different parts of your body to do different things. The instructions are sent through messages that travel down nerves, much like electricity travels down wires.

There are two different centers in your brain that control your heartbeat. One sends messages to slow it down and one sends messages to speed it up. The center that slows your heart rate down sends its messages from a wire or nerve called the vagus nerve. The center that sends messages to speed up your heart rate has a headquarters in what is called your cardio-acceleratory center. To accelerate means to speed up and that is exactly what it tells your heart to do.

Mind Munchie:
Did you know that if heart muscle cells simply listened to the signal started by your S.A. node, your heart would regularly beat about 100 times per minute at rest (when you are not performing any activity or movement at all)? When you are hanging out talking to friends or family, or watching television, you don't need your heart to beat 100 times per minute. It's a waste of heartbeats and a waste of oxygen. Although a walk to the refrigerator or up the stairs to your bedroom may require 100 beats per minute or more to move blood, sitting on your butt does not. So your heart rate really has to be adjusted from minute to minute, depending on what you are doing.

What is adrenalin and how does it affect your heart rate?

Adrenalin is a chemical that speeds up everything in your body including your heart rate. In addition to all of the messages sent from your brain centers, your body also has other means of getting revved up. Adrenalin works along with your brain centers to keep you moving when you need to keep moving.

Mind Munchie: You may have heard that athletes often have resting heart rates of less than 50 beats per minute. Why?

The slowing of heart rate by the vagus nerve is called vagal tone. Athletes have a lot of vagal tone for several reasons. First, they are lucky. They are genetically gifted. They are able to take in and use more oxygen with fewer heartbeats than the average person. This may allow them to be successful at sports or other athletic activities.

Second, because they are athletes, they probably spend a lot of time practicing their sports and a lot of time training their cardiovascular systems. An athlete's trained cardiovascular system and hereditary gifts are so good at getting oxygen and nutrients to their cells that much lower heart rates will do the job easily for them. Hearts that beat more slowly can spend more time resting and filling with blood. They just don't have to work as hard. By the way, you don't have to be an athlete to train your cardiovascular system.

How does blood flow up against gravity?

Blood flows up against gravity with the help of special valves that are inside of many of your veins. You might be surprised to learn that blood-flow to the heart is often against gravity. While you are standing, you might guess that your blood would drop to your feet. After all, your blood is heavy. What would make it flow upward any more than a waterfall would flow upward? The fact is your blood does flow upward to your heart. And it does that with the help of valves that are inside your veins. Many of your veins are designed to keep blood flowing up toward your heart.

All of the muscles of your body have blood vessels leading to them (arteries) and away from them (veins). When you move around, your muscles contract. When they contract, they squeeze the veins beneath them (remember, like the grip of your hand milking the cow). Your blood gets pushed upward and opens valves in your veins. The valve shuts behind it, stopping blood from flowing backward. If you keep moving, this pumping continues. It is this muscle pump that keeps your blood moving up toward your heart.

While you are walking or running, the blood is continuously and steadily returning to your heart. This is called venous return. Your heart automatically pumps out all of the blood that returns to it through your veins, just as quickly as it returns. The more blood that comes back to your heart, the faster your heart beats. The faster your heart beats, the more blood gets pushed out in each beat.

What is blood pressure?

Blood pressure is a measurement of the bang of your blood on the walls of your blood vessels at two different times:

	while your heart is contracting and squeezing out its blood (top number: systolic blood pressure)
	while your heart is relaxing (bottom number: diastolic blood pressure).

What is high blood pressure?

High blood pressure and atherosclerosis are diseases of the cardiovascular system. To learn more about prevention and treatment of these diseases through exercise, read these Physiology Phorums from the Physiology Storybook: An Owner's Manual to the Human Body, 2nd edition. Share them with students and colleagues. The book is available through the National Association of Sport and Physical Education