Butt breathing might help people struggling to get enough oxygen

anus: The opening at the end of an animal’s digestive system through which solid waste leaves the body.

biologist: A scientist involved in the study of living things.

blood vessel: A tubular structure that carries blood through the tissues and organs.

carbon dioxide: (or CO₂) A colorless, odorless gas produced by all animals when the oxygen they inhale reacts with the carbon-rich foods that they’ve eaten. Carbon dioxide also is released when organic matter burns (including fossil fuels like oil or gas). Carbon dioxide acts as a greenhouse gas, trapping heat in Earth’s atmosphere. Plants convert carbon dioxide into oxygen during photosynthesis, the process they use to make their own food.

clinical trial: A research trial that involves people.

conflict of interest: A situation where someone may have something to gain from (such as money, power or a job) by not making a fair or objective assessment of something. Journals, for instance, often ask the authors of journal papers to report any potential conflicts of interest that might affect their judgment of research data or conclusions as to their value.

freshwater: A noun or adjective that describes bodies of water with very low concentrations of salt. It’s the type of water used for drinking and making up most inland lakes, ponds, rivers and streams, as well as groundwater.

gills: The respiratory organ of most aquatic animals that filters oxygen out of water. Fish and other water-dwelling animals use gills to breathe.

gut: An informal term for the gastrointestinal tract, especially the intestines.

hue: A color or shade of some color.

infection: A disease that can spread from one organism to another. It’s usually caused by some type of microbe.

liquid: A material that flows freely but keeps a constant volume, like water or oil.

liver: An organ of the body of animals with backbones that performs a number of important functions. It can store fat and sugar as energy, break down harmful substances for excretion by the body, and secrete bile, a greenish fluid released into the gut, where it helps digest fats and neutralize acids.

organ: (in biology) Various parts of an organism that perform one or more particular functions. For instance, an ovary is an organ that makes eggs, the brain is an organ that makes sense of nerve signals and a plant’s roots are organs that take in nutrients and moisture.

oxygen: A gas that makes up about 21 percent of Earth’s atmosphere. All animals and many microorganisms need oxygen to fuel their growth (and metabolism).

pneumonia: A lung disease in which infection by a virus or bacterium causes inflammation and tissue damage. Sometimes the lungs fill with fluid or mucus. Symptoms include fever, chills, cough and trouble breathing.

recall: To remember.

tract: A particular, well-defined area. It can be a patch of land, such as the area on which a house is located. Or it can be a bit of real estate in the body. For instance, important parts of an animal’s body will include its respiratory tract (lungs and airways), reproductive tract (gonads and hormone systems important to reproduction) and gastro-intestinal tract (the stomach and intestines — or organs responsible for moving food, digesting it, absorbing it and eliminating wastes).

ventilator: (in medicine) A device used to help a person breathe — take in oxygen and exhale carbon dioxide — when the body cannot effectively do that on its own.