By David C. Simmons III

  Many come to the gym and want to change the way there body looks. But some have unrealistic

expectations of how much their bodies can really change. DNA and heredity are a couple of factors that can determine how much your body can change.

  There are some interesting things to know about DNA besides how it affects us through the generations.  
 This link helps to understand how exercise effects aging on a molecular level and how DNA is kept healthier with exercise; this helps our bodies to age slower.

  When exercising, always keep in mind that your DNA is being affected positively.  As opposed to eating bad and not exerciseing, and negitive environmental factors which could affect your DNA negatively.  When you are exercising, you are also exercising your DNA. A healthy DNA keeps you younger, this link says it can make you 9 years younger.  This is one more thing to remind yourself of when the going gets rough during exercise or when you’re wondering whether to skip it today or not.  

  You may not be able to tell how much success is due to genes vs. training in an individual athlete. But In a Gym, those that having been on a full out run on the  treadmill, the longest may be the ones suspected of having genes that are relevent to endurance (just as an example). .

   Now, all of that said, it is important to remember that genes perform only a supporting role in the outcome of training. So, if you are training to do long distance running, then, being genetically predisposed to having oxygen rich muscles will help your training. If you want to have the power and explosiveness of a half back, then being genetically predisposed to muscles that respond quickly with power and require less oxygen is what you want when you train.

As far as heredity and endurance. The distribution and size of blood vessels in your heart are genetically determined. The branching pattern of blood vessels leading to the lungs, total heart size and the size of the left ventricle which is where blood is pumped from into the rest of the body is genetically determined.
  When your eyes blink it’s because of a muscle. All muscles are made of cells. The energy that causes the cells to be able to move is from ATP. ATP is generated withing a part of cells called Mitochondria. There are hundreds even thousands of mitochondria in each cell. Genetically, Mitochondria initially come from your mother. The female egg has mitochondria, the fathers sperm does not!  However, through good aerobic programs, the number of mitochondria can be increased.  

  The percentage of muscle fiber types that one has is genetically predetermined.  If you’re born with a high percentage of oxygen rich muscle fibers, it will probably take your leg muscles longer to fatigue. This same person might then have a lower percentage of the other muscle fiber type that predisposes one to explosive strength. This person might lift weights for a year and may only grow so much and someone else with a higher percentage of this explosive muscle fiber may lift weights for a much shorter period of time and grow large muscles quickly.

 
   Here is a very interesting link on genetics and exercise !

    Ok, This is another link. It asked the questions "Are people using there genetics as an excuse as to why they cannot change their bodies ?" , and, "It talks about work-arounds for some who are genetically challenged. Hmmmm. The least it will do is give you some out of the box thinking about the whole issue
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(FYI – humans cannot grow new muscle fiber, they can only increase the size of existing muscle fiber. The number of muscle fiber is also of genetic predisposition!)
(FYI – Woman don't have as much muscle mass as men because they do not have as much testosterone. 90% of testosterone in men is produced in the testicles, the other 10% come from the adrenal gland. For woman, half of there testosterone comes from ovaries, the other half from the adrenal gland. For men ,testosterone mixes with human growth hormone to take the amino acids in the blood and turn them into protein -  (testosterone in men and woman)

   This link says you can increase your testosterone naturally.