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59 votes
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Why can't we kill ourselves by holding our breath?

Short answer Healthy people cannot hold their breaths until unconsciousness sets in, let alone commit suicide. Background According to Parkes (2005), a normal person cannot even hold their breath to ...
AliceD's user avatar
  • 52.5k
35 votes

Why can't we kill ourselves by holding our breath?

Counterexample: At least some people can train themselves to hold their breath until they pass out, and if this occurs underwater they will almost certainly die by drowning. When I was in military ...
feetwet's user avatar
  • 795
12 votes
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Will I hyperventilate if I breath twice as fast at an altitude with half as much oxygen as I am used to?

By definition, hyperventilation is a state of increased breathing where the exhaled $CO_2$ is greater than what is produced by the body. Except in artificial condition or in disease process, ...
Eliane B.'s user avatar
  • 1,145
9 votes

Can any other animal choke on food?

There are different kinds of choking on food. All non-gilled animals also choke when they fall in the water. Drowning is choking. insects asphyxiate and fish asphyxiate in air but technically insects ...
bandybabboon's user avatar
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9 votes
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What are the sources of molecular hydrogen in human breath?

Hydrogen in breath arises from normal intestinal bacteria, mainly in the colon, which break down (ferment) the undigested nutrients that have passed through the small intestine. Hydrogen is absorbed ...
Jan's user avatar
  • 8,079
9 votes

Are there land animals that use gill-like organs instead of lungs?

Terrestrial crustaceans are land animals that use gills (or gill-like structures) for gas exchange, though these gills must be kept moist for efficient respiration. Specifically, animals like hermit ...
acvill's user avatar
  • 8,296
8 votes

Cough at 1000 km/h?

This reference from CHEST lists 21 clinically measured peak flow rates during various modes of coughing. Of these patients, and for unassisted cough, the highest peak flow is about 4 liters/sec. The ...
docscience's user avatar
8 votes

Are there land animals that use gill-like organs instead of lungs?

Some terrestrial hermit crabs (genus Coenobita) have gills, but these are only partially responsible for their respiration1. These animals carry around water with them in the snail shell they 'wear'. ...
tyersome's user avatar
  • 5,598
8 votes

Why does exhaled air still contain oxygen?

You seem to be confused about diffusion versus bulk flow of fluid (air/gas). In the lungs, there is diffusion between blood and the gas in the lungs. There is sufficient surface area that these ...
Bryan Krause's user avatar
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7 votes
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Breathing faster to lose (more) weight?

The rate of CO2 production is normally set by the rate of metabolism and breathing rate is determined by the level of CO2 in the blood. What you are suggesting is known as hyperventilation. Because ...
Alan Boyd's user avatar
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6 votes
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Do people need nitrogen from air for health?

Do people need nitrogen from air for health? No. This is well established! Can people breath totally nitrogen-free atmosphere for a long time? Yes. Also well established! I know, nitrogen is ...
S Pr's user avatar
  • 6,262
6 votes
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Is unihibited exhalation beneficial for someone with a contagious respiratory disease?

Short answer No, there isn't going to be any benefit to an infected person by allowing them to breathe out virus particles freely. The number of viral particles breathed out is tiny relative to the ...
Bryan Krause's user avatar
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6 votes

Why is the partial pressure of oxygen in blood same as that in alveoli

There are three unfounded assumptions in your equation that I can see. You're treating partial pressure as a concentration. Partial pressures are not concentrations, though they're convenient ...
Bryan Krause's user avatar
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5 votes

Why does breathing increase in higher temperatures?

As you can see on the diagram below, oxygen solubulity in water drops by increasing temperature, so your fish has to breath more to get the same amount of oxygen. ref You can find more info about ...
inf3rno's user avatar
  • 4,460
5 votes
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Breathing with Clogged Nose during Sleep

Most people with colds/allergies/stuffy noses don't die in the middle of the night. Why? Prevention of oxygen deprivation is powerfully regulated. If insufficient air intake is possible through the ...
anongoodnurse's user avatar
5 votes
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How do fishes "breathe" while eating?

They can pump water over their gills with their opercular flaps (i.e., the structure that covers and protects the gills). This is assisted by the branchiostegal rays. Food would generally not ...
OliverFishCode's user avatar
5 votes
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Is too much CO2 in the air toxic?

CO2 forms carbonic acid in water, which helps to dissolve rocks and mountains in envitonmental science. It would slightly acidify your body with what is called a weak acid. 5% can cause acidosis and ...
bandybabboon's user avatar
  • 10.4k
5 votes
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External "lungs" that process your blood the same as your real lungs do - would that stop your need for breathing?

A device that fits your description does seem to exist, namely an ECMO machine that delivers extracorporeal membrane oxygenation (Fig.1 ). It is defined as: [A] machine [that] pumps blood from the ...
AliceD's user avatar
  • 52.5k
5 votes

How long could Jack Sparrow and Will Turner survive underwater with a row boat over their heads (Pirates of the Caribbean I)?

This is my attempted solution that I would like to share and verify. Volume of air. Assume dimensions of the boat (modeled a cuboid) = 4m x 1m x 0.5m Thus Volume of air, V = 2 m3. Acceptable limits ...
aalosious's user avatar
  • 175
4 votes

How do burrowing animals get enough oxygen?

As the body mass of an organism decreases, their volume decreases with direct proportionality, so their metabolic needs are also reduced. The result is that small organisms like worms and insects have ...
Sumanth Neerumalla's user avatar
4 votes

Why does breathing increase in higher temperatures?

In3mo informed about oxygen content varying with temperature, and another factor is the fish metabolic rate: Standard Metabolic Rate (SMR) is the metabolic benchmark in fish. It is the metabolic ...
bandybabboon's user avatar
  • 10.4k
4 votes

What is the average speed of human sneeze?

About 35-40mph According to the Mythbursters who subjected this to their tests showed that their own sneezes went around 35 to 40mph. This is anecdotal since it only has a sample size of two persons, ...
Hyfnae's user avatar
  • 238
4 votes

Can any gas other than nitrogen cause decompression sickness (the bends)?

Yes, it is possible to get decompression sickness with other gasses, such as the "oxygen bends" or oxygen decompression. For instance, in this study, they demonstrated that oxygen ...
rotaredom's user avatar
  • 2,711
4 votes
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Entry of particulate pollutants into the nasal cavity

Yes indeed, your quote has things backwards. Here is an image and a link to further information: ref If you follow the dotted line with your eyes - - - - - through the 1Micron grading... On the right ...
bandybabboon's user avatar
  • 10.4k
4 votes
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Why does hyperventilation make you feel like you need to breathe more?

Hyperventilation alone does not cause you to feel that you're not getting enough oxygen. Rather, it's what causes hyperventilation that does that (thus resulting in hyperventilation.) The Calm Clinic ...
anongoodnurse's user avatar
4 votes

Why can't fish extract oxygen from air?

From the Wikipedia page on gills that you link: The density of the water prevents the gills from collapsing and lying on top of each other, which is what happens when a fish is taken out of water ...
Bryan Krause's user avatar
  • 45.9k
3 votes

Breathing faster to lose (more) weight?

There are two organs which govern pH: the lung and the kidney. If one is having some problem the other steps in to correct it. The body does not like pH to drift far from 7.4. CO2 gas is blown ...
Willk's user avatar
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3 votes
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Why does the pulmonary artery have higher glucose concentration than the pulmonary vein?

Gas exchange doesn't but the cells of the tissue it occurs in do consume glucose, even the cells in the walls of the artery will consume some. The cells in the lungs still need to be fed and only one ...
John's user avatar
  • 14.7k

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