How the Lungs and the Cardiovascular Tissues React With Exercise
One of the most important activity we must participate in to live is to breath. Sometimes, I ask myself which really determines true death not clinical death; is it when you stop breathing, when the brain stops working or when your heart stops beating. Actually, you can hold your breath and still be alive, but when you are unable to take breath in, then you are obviously not living anymore. Clinical death is when the brain stops working and dies, but I am not doing that now, I am looking into breathing and the lungs. While we breath normally, but during exercise, the pulmonary respiration can go up to 20 fold and we know that with exercise, two organs play important roles and they are the heart and the lungs. I will be looking at the lungs and its function or morphology during exercise.
During breathing, the diaphragm which is the main breathing muscle will contract, pulling downwards giving space in the thoracic cavity where the lungs is situated, causing a decrease in the pressure in the lungs and the body. With this, the atmospheric pressure is greater than the pressure inside the body causing air to rush in to the body. The air enters the body through the nose (Nasal cavity), or the Mouth (Oral cavity), after which it moves to the trachea (wind pipe). The trachea starts to branch into the lung. As the trachea branches, the tube gets smaller until it reaches the Alveolar which is surrounded by capillaries which are the pulmonary capillaries. Oxygen moves from the Alveoli into the capillary then goes into the bloodstream, while carbon(iv)oxide leaves the bloodstream into the alveoli to be breathed out. During exercise, the respiratory rate increases, the number of breaths increases per minute, the volume of air also increases so as to provide oxygen to the skeletal muscles which have high need for it during exercise.
With increase in oxygen intake, could the lung capacity also increase? The answer is no, as the thoracic cavity doesn't increase, the diaphragm only contracts to provide room for the lungs to expand and contract during breathing. Is there a need for increase in total lung capacity? Is the total lung capacity the main reason for delivering oxygen during maximal exercise, not so. The heart, and blood vessels are also important in getting oxygen to the skeletal muscles, and the heart plays a major role in getting oxygen into skeletal muscle. The heart beats about 60 to 100 times per minute, which is about 100,000 times per day, about 35 million beats in a year and you can guess that it goes in for billions of beat in a lifetime. The heart is a pump with a main job of pumping blood to the tissues in the body. The left ventricle is the most powerful chamber of the heart, and it pumps blood to the entire body. It is thicker than the right ventricle of the heart. It pumps blood into the Aorta (which is the largest artery i the human body), which is then sent to other arteries which takes blood away from the heart and send blood into the body. Certain branches of the artery deliver bloods to the skeletal muscles, let me look at the quadriceps muscles, which receives blood from the femur artery. The artery send the bloods to the arterioles, which then send the blood to the capillaries. Capillaries allow for exchange within the blood vessels and the tissue it is delivering blood to or taking blood from.
Like I said, during exercise the oxygen demand increases. Oxygen will diffuse from the bloodstream into the muscles to satisfy the great need, also the waste and carbon(iv)oxide will leave the through the capillary. The de-oxygenated blood from body flows into the right atrium where it goes into the right ventricle then it will take blood into the lungs where it oxygenated again, and sent to the left atrium, then the left ventricle. The body requires three circulatory adjustment during exercise, which are increase in cardiac output, vasoconstriction of peripheral arterioles, and contraction of the walls around the veins in the body. The heart rate and stroke volume affects cardiac output, which is the amount of blood being pumped out per time. Stroke volume is the amount of blood per volume pumped out at each beat. These factors increase during exercise, so the heart changes during exercise, as well as the skeletal muscles but the lungs do not increase. While the lungs doesn't increase, as the cardiovascular tissues and organ adapts during exercise they will be able to utilize more oxygen from the lungs, allowing the muscles to get more oxygen as the expand as well.
With exercise, Oxygen diffusing capacity of the lungs can improve. This is the rate at which oxygen moves from the alveoli to the pulmonary capillaries, which could be as a result of increased amount of capillaries in the alveoli which is in the lung tissue. Also the diaphragm and intercostal muscles get stronger with exercise. These are the major effect that could be seen in the lungs with exercise, it is basically meant to provide oxygen during exercise, while the heart pump the oxygen to the tissues that need it to function properly. The heart, the intercostal muscles, the diagphram and the skeletal tissues would experience changes as people perform exercise regularly and go beyond their previous endurance level.
- https://pubmed.ncbi.nlm.nih.gov/18227881/
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4818249/
- https://www.nhlbi.nih.gov/health/lungs
- https://www.kenhub.com/en/library/anatomy/anatomy-of-breathing
- https://www.sciencedirect.com/topics/medicine-and-dentistry/ventilatory-response-to-exercise
- https://www.nhsinform.scot/illnesses-and-conditions/heart-and-blood-vessels/about-the-heart/understanding-how-your-heart-functions
- https://www.ncbi.nlm.nih.gov/books/NBK279250/
- https://www.nebh.org/blog/how-does-exercise-affect-your-heart-and-what-are-the-benefits/
- https://my.clevelandclinic.org/health/articles/9445-diaphragmatic-breathing
- https://pubmed.ncbi.nlm.nih.gov/8991553/