Wednesday, February 9, 2011

Channeling you inner electricity - Part I

When you talk of green energy, nothing beats the human body. We have the power to generate electricity that runs bodily functions. An average adult human body generates about 80 Watts of power at rest and the human heart can generate about 7 Watts of power. As a cardiologist, on a daily basis I see evidence of the ability of the human body to generate electricity. A simple EKG or electrocardiogram is proof of that. On an EKG you see positive and negative deflections depicting the voltage of the recorded electricity. The human heart is a fascinating organ. It has the ability to constantly put out electricity that runs the mechanical pumping portion of the heart. As will be explained later on, the impulses to run this electrical generator does not cease till we die. The ability to use these impulses to turn on the electricity generating capacity in the body changes with disease states, medication use and some genetic factors.

Electricity generation in the heart is based on ion fluxes (ions such as positively charged sodium, potassium and calcium). A description of the fundamental properties of the currents mediated by ion channels by British biophysicists Alan Hodgkin and Andrew Huxley won them the Nobel Prize in 1952. The heart is composed of millions of cells. Each cell has a wall around it called the cell membrane and this membrane has little doors called ion channels. Electricity that the heart generates is based on a simple principle. These ions (sodium, potassium and calcium) move in and out of the cells through ion channels or doors. These ions carry a positive charge. If the majority of these ions are outside the cell, the cell is negatively charged. The door or ion channel opens and these cells are flooded with positively charged particles and this creates a charge gradient between the outside and inside of the cell, generating electricity. First sodium enters the cells, taking the cell from negative to positive polarity, then calcium enters the cell leading to muscle contraction and then potassium leaves the cell bringing the polarity of the cell to the negative resting state. All this depends on the ion channels opening and closing. Using X-ray crystallography, scientists have only recently been able to show what these ion channels look like. These channels differ in appearance depending on the ions passing through. Nerves, muscles and other cell have these channels. These ion channels are made up of protein. They are activated by neurotransmitters such as acetylcholine and adrenaline which work in 2 parts of the autonomic nervous system, the parasympathetic or “rest and recover” (acetylcholine) and sympathetic or “fight, flight, fright” (adrenaline) arms.  

You may have heard of cardiac medications such as beta-blockers and calcium channel blockers. Beta receptors on the heart muscle when activated by adrenaline, increase the heart rate and force of contraction. Beta-blockers work by blocking receptors that provide an attachment point for adrenaline. Calcium receptors in the heart are generally “voltage gated”, in other words, they open or close in response to changes in voltage mediated by influx of sodium into the cells. Calcium channel blockers block these calcium “gates” and the heart contracts less forcefully. Apart from action of medications on receptors in the heart, other factors can also influence electricity generation. As we trace the path of electricity backwards, you will be able to appreciate various factors along the way that can potentially influence this process positively or negatively. Why is this important to know? Since the heart is a muscle, it is subject to fatigue. Your entire life depends on the proper functioning of this organ.

Electricity that the heart generates can be modified or triggered by two arms of the autonomic nervous system. The autonomic nervous system is a network of nerves that controls vital bodily functions. It functions below the level of the mind and consciousness. In other words, these two arms, the sympathetic and parasympathetic nervous systems can be compared to driving uphill and downhill. When you are driving uphill, you have to step on the gas. In the body, when we are faced with a “fear, flight or fight” situation, the sympathetic arm is activated helping us rev up the bodily mechanism to appropriately respond. When we are coasting downhill, we don’t have to step on the gas. The engine has time to rest. This is what happens when the parasympathetic nervous system is activated, the heart slows and gets a break, aiding the heart in rest and recovery.

We have explained the mechanism of electrical generation the in the heart, the trigger for electrical generation, namely the sympathetic (fear, flight, flight response) and parasympathetic (rest and recovery) arms of the nervous system.

In the next part, we’ll explore how the neural connections and the mind fits into this and how we can modify the actions of the nervous system through our breathing. It is very important to know how to consciously “rest” the heart, as the heart is subject to wear and tear just like an automobile that is running at high speed all the time. The heart, although very small in size is vital to the body, just as a small wheel is vital to an aircraft taking off. When you fly in an airplane, the last thing you think of is the wheel. When you live a fast and reckless life, the last thing you think of is the effects of this lifestyle on the heart, until you start experiencing the effects of the wear and tear on your heart.  

To be continued...