Initiation of exercise
The body needs enough energy to adjust to the increased physical activity being experienced. In order to ensure that enough blood will circulate through the entire body, the respiratory system will work double-time in order to adjust.
Moderate exercise
During moderate intensity exercise, the body will need more oxygen in order to keep up with the moderate intensity exercise, thus increasing lung capacity and ventilation rate.
Abrupt ascent into high altitudes
The atmosphere thins as a person ascends into higher altitudes, meaning there is less oxygen present for a person to consume. In order for the body to adjust to this abrupt change, the lungs hyperventilate in order to supply enough oxygen to the tissues.
Paralysis of phrenic nerve
The phrenic nerve is in charge of the diaphragm's movement. Thus, paralysis of this nerve may lead to diaphragmatic paralysis or dysfunction.
Severe anemia
Since the main function of the red blood cells is to carry oxygen from the lungs to the other parts of the body, a lack thereof means that the body is not getting enough oxygen to support the body. To attempt to make up for this, a person experiencing severe anemia experiences hyperventilation and an increased heart rate.
Advanced pregnancy
A woman's hormonal and physical changes during advanced pregnancy may affect their air intake. Additionally, since the diaphragm is compressed due to the growing fetus, the mother's lung capacity decreases.
References:
Braunstein, E. M. (2023, October 13). Anemia of chronic disease. MSD Manual Consumer Version. https://www.msdmanuals.com/home/blood-disorders/anemia/anemia-of-chronic-disease
LoMauro, A., & Aliverti, A. (2015). Respiratory physiology of pregnancy. Breathe, 11(4), 297–301. https://doi.org/10.1183/20734735.008615
Tortora, G. J., & Derrickson, B. H. (2018). Principles of anatomy and physiology. John Wiley & Sons.
Vissers, H. (n.d.). Altitude Training and its Effects on the Human Body. https://minds.wisconsin.edu/bitstream/handle/1793/72215/HaleyVissers.pdf?sequence=1#:~:text=One%20change%20experienced%20in%20the
West, J. B. (1982). Respiratory and circulatory control at high altitudes. The Journal of Experimental Biology, 100(1), 147–157. https://doi.org/10.1242/jeb.100.1.147
Your lungs and exercise. (2016). Breathe, 12(1), 97–100. https://doi.org/10.1183/20734735.elf121