1) What is the primary physiological challenge to exercise in hypoxia?

2) What are the consequences on O2 saturation and content? 

 

1.What is the primary physiological challenge to exercise in hypoxia?

Hypoxia is a condition in which the body or a region of the body is deprived of adequate oxygen supply at the tissue level. Hypoxia may be classified as either generalized, affecting the whole body, or local, affecting a region of the body.

The efficiency of exercise is determined by the supply of oxygen to functioning muscles and vital organs, including the brain. In the hypoxic environment, maximal exercise efficiency and oxygen uptake (V ? o2) are decreased at altitude or with simulated hypobaric or normobaric hypoxia. Oxygen-enriched air [normobaric hyperoxia, increased fraction of inspired oxygen (FIO2)], on the other hand, can improve exercise efficiency in healthy individuals and, potentially to an even greater extent, in patients with exercise-induced hypoxemia-related respiratory diseases such as pulmonary hypertension (PH) . Therefore, studies on the impact of breathing oxygen-enriched air near sea level on the performance of exercise in healthy individuals and patients with respiratory disease can help to identify mechanisms involved in the limitation of exercise in normoxia and altitude hypoxia. Exercise efficiency is determined by the cardiorespiratory system's oxygen supply to the muscles, the diffusion of oxygen from the capillaries into the cells, and the skeletal muscles' use of oxygen. The supply of oxygen by the cardiorespiratory system can not satisfy the metabolic demand at higher exercise intensity, and the accumulation of H+ and inorganic phosphates at the neuromuscular junction and in the muscle cells limits contractility and causes fatigue. The progressively insufficient supply of oxygen to the brain at the same time has been suggested to restrict exercise by ceasing the central command of the locomotor system.

The oxygen delivery system to organs at rest and even more during exercise, when skeletal muscular oxygen demand increases dramatically, is threatened by exposure to hypobaric hypoxia at altitude. Acute high altitude exposure causes a rise in breathing and heart rate, powered primarily by activation of the carotid chemoreceptor caused by hypoxemia, sympathoexcitation, and vagal withdrawal. The initial increase in cardiac output mediated by the heart rate compensates for the reduction in the content of arterial oxygen, such that the result of both, the delivery of systemic oxygen, remains unchanged at rest . The resting cardiac production normalizes with sojourns at altitude for many days through a decrease in stroke rate, which is due to a drop in plasma volume caused by hypoxia and hence lower left ventricular end-diastolic volume.

2.What are the consequences on O2 saturation and content? 

Inside the body, oxygen is closely regulated because hypoxemia can cause many immediate adverse effects on individual organ systems. These involve the kidneys, heart and brain. In relation to how much hemoglobin stays unbound, oxygen saturation tests how much hemoglobin is actually bound to oxygen. Hemoglobin is made of four globular protein subunits at the molecular level. Per subunit is associated with a group of hemes. Subsequently, each hemoglobin molecule has four heme-binding sites readily available for oxygen binding. Therefore, hemoglobin is capable of holding up to four oxygen molecules during blood oxygen transport. It is important to be able to control current oxygen saturation due to the vital nature of tissue oxygen intake in the body. A pulse oximeter can measure the saturation of oxygen. It is a noninvasive device put over the finger of a human.

To assess the ratio of existing amounts of oxygenated hemoglobin to deoxygenated hemoglobin, it tests light wavelengths. In medicine, the use of pulse oximetry has become a quality of treatment. It's also considered to be the fifth vital sign. As such the functions and drawbacks of pulse oximetry must be recognized by medical practitioners. They should have a clear understanding of oxygen saturation as well.

Blood disorders, circulatory problems, and lung issues may negatively affect your blood oxygen saturation level, as they may prevent you from adequately absorbing or transporting oxygen. Examples of conditions that can affect your O2 sat level include:

• Chronic obstructive pulmonary disease (COPD), including emphysema and chronic bronchitis
• Asthma
• Collapsed lung (pneumothorax)
• Anemia
• Heart disease
• Pulmonary embolism
• Congenital heart defects