Cardiorespiratory and hormonal adaptations to exercise and training
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Cardiorespiratory and hormonal adaptations to exercise and training
Cardiorespiratory system; adaptations to training; hormonal control
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Hormonal Case Study

Q.  You are a personal trainer of a very stressed 41 year old business man who is training for a half-marathon.  Explain the effects of exercise on his endocrine system, the likely hormones he will be secreting and why; and how this might impact on his ability to train effectively for the half marathon.


With stress he experiences at work his body will be regularly producing adrenaline from his adrenal medulla and cortisol from the adrenal cortex, hormones of the autonomic nervous system.  Adrenaline raises our BP, ups our heart rate, sends energy to our cells and constricts the vessels in our digestive system.  Cortisol helps replenish energy stores and works with the immune system to isolate pathogens so works for our long term metabolism .   Increased activity of the autonomic nervous system elevates our blood sugar levels, promotes hypertension, raises LDL and drops HDL. 

The main hormones responsible during exercise are testosterone, growth hormone, thyroid hormones (T3,T4), adrenaline, cortisol, insulin, aldosterone and EPO.  These all play a role in maintaining energy production to our muscles through the metabolism of FFA's and carbs, keeps our fluids balanced and maintains homeostasis of the cardiovascular system.

Due to his stressful job he will be living with an increased BP and HR may have beginnings of arteriosclerosis.  His nutrition and nutrient absorption will also be hindered with the digestive system being regularly turned off.

His heart will be under constant pressure to maintain effective cardiac output, this may also be affected by arteriosclerosis.  The insulin receptors on his cells will be tired from the constant elevated blood sugar levels so will be heading towards Type 2 diabetes.

With the exercise his body will get tired from trying to maintain homeostasis and something will eventually break. This is the age in males that have a high incidence of exercise induced myocardial infarction.  Hope not in this case!


Posted by Frith. 30/08/12

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Intra pleural pressure actually is



The pleura is a double sided membrane that covers the lungs.  The inner surface (visceral layer) is attached to the lungs.  The outer surface (parietal layer) is attached to the chest wall or thorax.  In between is pleural fluid, this fluid acts as a type of CRC, it makes the two surfaces slide over each other.  I've heard this described as 2 plains of glass stuck together with water, they slide over each other but won't come apart easily.  All of the components above make up the pleural membrane and the fluid is the intrapleural space. 

There are 3 main pressure systems affecting respiration.  These are the atmospheric pressure (air around us), the intrapulmonary pressure (air inside our lungs) and the intrapleural pressure.  Atmospheric pressure and intrapulmonary pressure are both positive pressure systems.  I have heard this described as somebody blowing on a piece of paper, the air pushed the paper away.  Intrapleural pressure is governed by negative pressure, this is like a bag sealing machine, the air is sucked out of the bag forcing the 2 sides together. 

The negative pressure in the intrapleural space is what keeps our lungs inflated.  The visceral layer (attached to the lungs) is sucked onto the parietal layer (attached to the thorax) with the intrapleural space ensuring some fluid movement during respiration.





* Intrapleural pressure will not stay the same it is very constant during inspiration and expiration stages and the respiratory system


 * The chest wall wants to expand, while the lungs try to collapse


*This will decrease  pressure in  lungs will cause a change in the pressure gradient


 * The atmospheric pressure and  air flows into the lungs wants to equalize this gradient.


 *the intrapleural space is located  between the area of the lungs and the area of the chest wall


* Airway ,  alveolar pressures will become very negative during the inspiration stages . Both of these important factors cause this thing called intrapleural pressure to become more negative.than before .


By Gav G Unit , and by Frith



Aoraki Exphys's comment, August 1, 2012 7:29 PM
Thanks Gav and Frith.
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Physiology Cardiovascular System

Physiology Cardiovascular System | Cardiorespiratory and hormonal adaptations to exercise and training |

The cardiovascular system comprises of the heart, blood, blood vessels and lymphatic system from the brianmac website.  Posted by Frith

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Various adaptations occur during long term physical training.  It depends on various factors within an individual athlete as to how long these adaptations can take.  Some adaptations can be noticed within weeks, others up to 18 months.  Training will need to be over 30-60 mins, 4-5 times per week.  Some of these adaptations are:


-  The hypertrophy (increase in muscle size) adaptations seen with resistance training are a net result of subcellular changes within the muscle which include: more and thicker actin and myosin protein filaments, more myofibrils (which embody the actin and myosin filaments), more sarcoplasm (the fluid in the muscle cell), and plausible increases in the connective tissue surrounding the muscle fibers (Wilmore & Costill, 1994) . In addition, fast-twitch (glycolytic) muscle fiber has the potential to show greater increases in size as compared to slow-twitch (oxidative) muscle fiber (Hather, Tesch, Buchanan, & Dudley, 1991).


-  The motor units develop more efficient neural pathways to supply the muscle fibres.  It is possible that two adjacent muscle fibers, with different motor nerves, could result in one fiber being activated to generate force while the other moves passively.  This all contributes to enhance the muscle's ability to generate more force.


- Increased blood flow to the muscles by increased capillarization of trained muscles, greater opening of existing capillaries in trained muscles, increased RBC count, more effective blood redistribution, increased blood volume, decreased blood viscosity & increased oxygen delivery.


-  Our bones begin to remodel themselves by stimulating the production of collagen and osteoblasts to create more bony matix.  This results in our bones becoming stronger and more rigid. This means increased bone density.


-  Physical training will increase our fat free mass and ultimately reduce our overall body fat.


-  Our left ventricle becomes thicker and stronger which allows more systemic blood flow.  This increases our cardiac output (Heart rate x Stroke volume) at rest and at maximal.  This increases the rate at which we can deliver oxygen to our muscle cells and remove the waste products from cellular respiration.  Due to this the elastic recoil of the left ventricle increases (Frank-Starling Law).


-  Our resting heat rate decreases due to the increased parasympathetic (rest, digest) activity and decreased sympathetic (fright, flight) activity.


- Decreased maximum heart rate.  If your heart rate is too fast, the period of ventricular filling is reduced and your stroke volume can be compromised.  The heart expends less energy by contracting less often but more forcibly than it would by contracting more often.


- Decreased resting blood pressure, but is unchanged during exercise this is from increased blood flow to the arteries.


- Increased blood volume (blood plasma) and is greater with more intense levels of training because of an increased release of antidiuretic hormone, increased plasma proteins which help retain blood fluid, increased red blood cell volume and decreased blood viscosity.


-  There is a slight increase in total lung capacity and lung volume.


-  A decreased resp rate at rest and at submaximal due to greater pulmonary efficiency.


-  An increased pulmonary diffusion during maximal exercise from increased circulation and increased ventilation and from more alveoli involved during maximal exercise.


- Lactate threshold occurs at a higher percentage of VO2 max from increased circulation and increased ventilation and from more alveoli involved during maximal exercise.


- Decreased Respiratory Exchange Ratio (ratio of carbon dioxide released to oxygen consumed) from a higher utilization of fatty acids instead of carb’s


- A significant increase in BMR due to the increase in muscle mass.


- Decreased VO2 during submaximal exercise from a metabolic efficiency and mechanical efficiency.


-  Large increases in VO2 max capability.


  Posted by Frith


















Aoraki Exphys's comment, August 13, 2012 5:31 AM
Nice work here Frith. Kerensa
Aoraki Exphys's comment, August 13, 2012 5:32 AM the spelling!
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Physiology Endocrine System

Physiology Endocrine System | Cardiorespiratory and hormonal adaptations to exercise and training |
The endocrine system affects bodily activities by releasing chemical messages, called hormones, into the bloodstream from exocrine and endocrine glands...
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Cardiac conduction system and ECG.wmv

This video provides an excellent descrition of the cardiac conduction system and ECG trace...  Used this with my ambo training.  Breaks it down really well.  Posted by Frith

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