All day and at every moment, we breathe. While we eat, walk, run, climb a hill and even when we sleep, our body must oxygenate itself. The demands however, are not the same for each activity, reason for which the body has the incredible ability to adapt to both the environment and the demands of the actions we are performing. Once again all the structures, organs and even other systems involved (like, for example, the cardiovascular or digestive) coordinate and achieve the necessary response to capture the necessary oxygen from the exterior and discard the harmful carbon dioxide.
Physical activity and respiration
During physical exercise (especially in high performance competitions), not only our pulmonary ventilation increases. The heart rate as well as the blood flow must adapt to the new conditions and demands of the body.
Every time we perform an activity that demands energy, our oxygen consumption and production of carbon dioxide directly increase.It is for this reason that our body prepares itself, even before performing the exercise, in order to better respond to this physical demand.
We will analyze what happens with the respiration of an athlete during a sprinting race. Before beginning the competition, the encephalon takes care of emitting a series of nerve impulses that are common in physical preparation. The respiratory rate increases and the speed of blood circulation, once the race begins, increases approximately by six.
This situation implies that the faster the blood circulates, the higher the heart rate and exchange between oxygen and carbon dioxide at an alveolar level.
Blood is lead from the areas of low activity (in this case it could be organs and tissues of the digestive system) towards those that have a greater need, in this case, the muscles involved in a race. These muscles are also stimulated by the signals transmitted by the motor area of the cerebral cortex, which also sends signals at the same time to the cerebral respiratory centers. Upper as well as lower limbs send multiple sensory signals that travel through the spinal cord and end their ride in a respiratory center, stimulating it. Once the competition is over, ventilation as well as heart rate quickly drop, not so body temperature, which decreases little by little.
Matter of altitude
One of the phenomena that directly affects respiration and adapts it to the demands of our body is the altitude of the place we are located (meters above sea level, masl).Generally, people can withstand, under normal conditions, up to an average altitude of 2,500 masl. However, over this indication, and as one goes higher, the gas exchange is altered by the low pressure of the inhaled oxygen. This doesn’t mean that at a higher altitude there is less oxygen, it means that the drop in pressure decreases the number of molecules captured in each breath.
Once at 5,000 masl, the supply of oxygen goes down to half, both at rest and in action. The phenomenon is known as «altitude sickness» and among its symptoms we find: strong headaches, dizzy spells, vomiting and insomnia.They can be countered through «acclimatization» regarding the reached altitude. This means, to slowly get used to the new conditions in order for our body to generate more red blood cells and for breathing to become deeper, achieving a balance between the amount of oxygen inhaled and the needs of our body. This is a gradual process that can last a few days and varies depending on the person.
Submarine pressures
Water is much heavier than air: approximately, 800 times heavier. It is for this reason that the pressure of water upon the human body is also stronger. Contrary to what happens at high altitude, the more we descend, the pressure of the water on us increases, reason for which divers and explorers must use certain instruments (special suits, tubes of compressed air, etc.) to perform their tasks with minimal complications.
Once the great barrier of respiration under water is overcome, it is necessary to prevent a serious affliction that can have fatal consequences for the human being.Let us recall that over 70% of the air we breathe is made up of nitrogen. It is also the main part of the atmosphere and is present in vegetable cells as well as animal cells and in diverse organic materials. In the respiratory process, this compound only goes in and out of the lungs and also acts to dilute oxygen.
However, its concentration and distribution in the human body varies when we are submerged at great depths (30 meters or more) and when we suddenly emerge towards the surface. This is when decompression sickness is produced, also known as
diver’s sickness.
Once one rapidly ascends to the surface, nitrogen starts to bubble in our bloodstream. If we go up abruptly, we don’t give this compound enough time to dilute and escape the tissues, reason for which true gas bubbles are formed that can obstruct the blood conduits, damage the tissues, or settle in the articulations (joints) causing intense pain.
Attached respiratory movements
There are a series of movements that are directly related to respiration and the structures that participate in this process. Although they are not vital activities and some of them are even bothersome, they happen to us everyday and can be an indication of some disease.
One of these movements is the hiccup, which consists in a series of involuntary and sudden contractions of the main muscle involved in respiration: the diaphragm. The characteristic sound of the hiccup is caused by the sudden closing of the vocal cords; its starts for no apparent reason and goes away after a few minutes (except for people that suffer persistent hiccups).
The hiccup can even present itself during fetal development, during the second and third trimester of gestation. The mother is capable of perceiving the rhythmic movements of the baby that can last a few minutes, without getting to disturb him.The sneeze is also considered a respiratory motion and is a reflex which is characterized for presenting an unexpected inspiration we cannot repress, followed by a more violent expiration. This last one can reach (in its exit through the nasal ducts and/mouth) between 110 and 160 kilometers an hour.
The yawn is a deep inspiration (in it, we open our mouth wide to capture air) in which we don’t have to have our nostrils clear because inspiration as well as expiration, generally, is performed through the mouth. Its use is unknown, but it implies other parallel actions (stretching of the facial muscles, salivation, tearing, among others).
Coughing is the sudden contraction of the thoracic cavity. In it, air is violently released from the lungs after a deep inspiration.It can present itself automatically, but is usually associated to certain stimuli of chemical, mechanical or thermal origin, among other causes.
