Varying Weight Training Intensity Increases Growth Hormone In Women

How Weight Training Increases Growth Hormone

This study produced by the American Physiological Society found that women who are involved in a long term weight training program will produce more growth hormone. The study involved  the following scientists and universities : Kraemer, Jeff S. Volek, Barry A. Spiering and Carl M. Maresh of the University of Connecticut, Storrs; Bradley C. Nindl, U.S Army Research Institute of Environmental Medicine, Natick, Mass.; James O. Marx, The University of Pennsylvania, Philadelphia; Lincoln A. Gotshalk, University of Hawaii at Hilo; Jill A. Bush, University of Houston, Texas; and Jill R. Welsch, Andrea M. Mastro and Wesley C. Hymer, The Pennsylvania State University, University Park, Penn.  It seems that the female body is more complex than previously thought. This study was produced in 2006 and was published the American Journal of Physiology Endocrinology and Metabolism. The investigation shows that women are capable of building strength and muscle. It also allowed physiologists to understand to a greater degree how weight training in general improves metabolic function and muscle mass. Growth hormone was responsive to moderate and heavy exercise under regimens that contained 3 to 12 repetitions with varying loading. If women are attempting to build as much strength as possible then their load bearing activities must vary. This is also beneficial for building a stronger skeleton and avoiding bone related diseases. The role of endocrine function is more intricate than previously thought. This is why women’s endocrine physiology must be considered to create training programs to enhance performance.

         Hormones are chemical messengers that are transported through the blood stream. They are directed by an endocrine gland  or isolated gland cells which allows for a physiological response to be triggered. This happens in cells that contain receptors for a particular hormone. Hormones can be categorized in three different classes.

Hormone function

These classes are peptides, monoamines, and steroids. The pituitary gland must labor hard to maintain  Hypothalamic–pituitary–target-organ axis. Hormones are just one way in which the human body can communicate from cell to cell. Gap junctions, paracrines, and neurotransmitters perform these functions. Growth hormone acts as a repair worker acting as a builder. Its function is anabolic based. Somatotropin (growth hormone)  expains why children rapidly grow when the reach a particular stage in puberty. The pituitary gland is the conductor, which resides near the hypothalamus. It has a posterior  and anterior  section which both sections produce hormone for the body.  Hormones are not only important to communication between organ systems, but they do effect the performance and training of an athlete.

     The endocrine function is different for females compared to males. It was once believed that women were at a physical fitness disadvantage, because they produced more estrogen. Men’s greater testosterone allows for a body of lower body fat percentage and more muscle mass. However, it seems that when women train at a certain intensity, growth hormone acts a source of muscle and bone development. So, there is not a hormonal disadvantage rather a physiological difference. If the female body does not produce high amounts of testosterone, it merely relies on another hormone to produce bone and muscle growth in response to stimuli.  Depending on the fitness training stimuli the results would be better for building strength on ones that cause growth hormone to respond. Growth hormone is produced in the pituitary gland and has other functions. It contributes to halting tissue break down, fighting stress fractures, and improves metabolic function.

Growth hormone molecules  are composed of 191 amino acids. These molecules are capable of fragmenting into smaller units. These fragments can attach themselves to other molecules. Growth hormone can also attach itself to binding protein. There exists 100 variations of the growth hormone molecule. Growth hormone comes in different forms depending on its function and role in a particular task.  What researchers did in this study was to used the technique of measuring immune response. Immunoassays are examinations that are conducted by physiologists to detect changes in the immune system. The   tibia line rat growth assay also detects biological function of hormones.To find out more the experiment involved subjects doing exercise for a certain period of time.

        The experiment involved subjects separating into two groups. The first group would train upper bodies only. The second group of participants would perform total body training . The reason for separating the training in this fashion was obvious. If women have lower levels of upper body strength and can increase it through training, it would be easier to detect hormonal or physical changes in this region. Women do not have stronger legs than men, but are closer in strength to men in that region of the body.

There was also a subdivision within those groups. Half used heavier  weights with fewer repetitions. The other sections used lighter one with a more repetitions going up to twelve. Blood samples were acquired both prior and after the training experiment. This experiment lasted for 24 weeks. This was enough to make several conclusions and assessments. The presence of growth hormone depended on the exercise or training regimen used. Growth hormone’s appearance varied with the test used  for detection. This implies that the pituitary gland adjusts the amount of growth hormone relative to weight training stimuli. The body possibly has the ability to adjust the amount of growth hormone or type depending on the activity. The larger sized variants of growth hormone will be produced more if a woman does more heavy lifting.

sperling_fig2_450_288_42087 Growth hormone has multiple functions in the human body. There is a possibility that it has an effect on muscle fiber distribution fiber itself. Growth hormone also contributes to both amino acid transport and metabolic tissue energy expenditure. There are different types of growth hormone, but they will not respond in the same way. It is unknown what effect oral contraceptives would have on women in relation to this. The authors of the study intend to investigate that further. There should be some factors that could have effected the experiment. The tests given may not be as precise when measuring hormone changes in the blood stream. It does not seem like a major factor, however could women’s menstrual cycles effected them during the training sessions? Also it should be accounted for the fitness level of the participants. If there were women who had weight training experience, this may cause an alteration in data. If another experiment were to be done it may have to be another subdivision with women in an experienced or non-experienced weight training group. So far, it looks as if this is correct, but it needs more study.

           This would seem like an advantage in terms  of endocrinology in regards to women embarking on fitness programs. This would not be enough to close the physical strength gap between the sexes. Growth hormone as the study indicates functions similar in a role of what testosterone who do in a male under a particular training regimen. It is not an exact substitute, rather it is a difference produced from sexual dimorphism. Puberty and the physical changes that come from it explain the differences in elements of physical fitness capacity. Women produce lower levels of testosterone, but it does serve a purpose in their bodies. Bone strength and ovarian function are the roles testosterone plays in females. The hormone may also be important to women’s sexual functioning as well. The physical changes are documented by the Tanner scale, a chart that displays the gradual development of the body during puberty. James Tanner developed the modern growth chart as a guide for pediatricians. He also was a pioneer in using human growth hormone to treat children with endocrine disorders related to body development. During the tanner stages men’s testicles will increase in size increasing the amount of free testosterone in the body. Ovaries produce more estrogen compared to androgens. There are five stages on the tanner scale in which genitals and body composition will change due to the function of the endocrine system. Pubic hair emerges in both sexes and physical growth will transition a child’s body to a full grown adult. Men get their strength spurts around the fourth and fifth tanner scales. Women do not get strength spurts during this stage of the human life cycle.

Prior to puberty there is no difference in strength levels between boys and girls. When puberty causes hormonal changes which increases men’s physical fitness capacity. This mean under the same  training conditions women would not reach the same strength levels. Theoretically, if a woman were to train with a method that increased her somatotropin levels, she may get stronger than she would have with another technique.There still is a question about what are the full extent of women’s physical capabilities see as it has only been recently that there has been study on this subject. The nature and function of hormones relative to training seems more intricate than what exercise physiologists would have expected. This new information could also contribute to medical advancements as well. There is still more to learn about the human body and women’s bodies in particular.



Varying Weight Training Intensity Increases Growth Hormone In Women

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