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鈥淛ust breathe!鈥� is probably the worst thing that you can tell someone who is hyperventilating. The fact is, they can鈥檛! Whatever the cause of the hyperventilation, screaming and telling someone to just 鈥渃alm down鈥� may actually worsen the situation. Don鈥檛 fret, there is still a way you can help, and it is actually quite simple. Offer them a paper bag to breathe into. We have all seen it done in movies or tv shows but this seemingly trivial solution is quite effective, but why?

Hyperventilation involves chemistry?

Before we delve into the answer, it is important to understand what hyperventilating actually means. Surprisingly, the movies aren鈥檛 far off from their depiction of the syndrome on the screen hence hyperventilation is categorized as erratic and increased breathing. This unusual breathing pattern has some underlying chemical effects on the body which can cause light-headedness, numbness or tingling of the arms, overall weakness and shortness of breath. These symptoms are brought on by a chemical imbalance in the body. Who would have known that hyperventilation is related to chemistry?! When breathing normally we inhale oxygen (O₂) and exhale carbon dioxide (CO₂) at our body鈥檚 accepted rate and gas concentration levels. The two gasses participate normally in the respiration process and the body can continue functioning undisturbed. When someone begins to hyperventilate, they tend to exhale a lot deeper and more frequently than they inhale which causes a decrease of CO₂聽in the body. This may seem insignificant because 鈥渄on鈥檛 we breathe out CO₂聽anyways? Why do we need it in our bodies?鈥� Although carbon dioxide is exhaled, our body needs a certain level of it in the blood to maintain equilibrium or balance. When we have less of it, there is a cascade of reactions that begin to occur to try and compensate for the loss.

Cascade of internal reactions

So, we established that we need CO₂聽to maintain balance in the body but what actually happens when we don鈥檛 have enough of it? Carbon dioxide exists in our body in an aqueous form hence our blood is mostly composed of water. When CO₂聽reacts with the water in our blood, the following reaction occurs:

Now, don鈥檛 be frightened by the chemistry. This equation just means that water and carbon dioxide combine to form carbonic acid (H₂CO₃). The double arrow means that this process is reversible and that its equilibrium position can shift according to how much of each compound is present. This initial reaction is the first of many in the cascade of reactions that CO₂ is involved in. The carbonic acid produced in equation 1 is actually unstable in its environment and will dissociate into bicarbonate and hydrogen ions as follows:

Even though you can鈥檛 see the CO₂聽it鈥檚 still there, but it has just been converted into compounds that are more useful to the body. To make the products of equation 2 CO₂ is required, which means that the quantity of carbon dioxide in the body indirectly affects the production of bicarbonate and hydrogen ions (important to remember). Now, what happens when we are lacking CO₂? Both reactions 1 and 2 have double sided arrows which means that the process falls into a dynamic equilibrium. This just means that whatever change is imposed on the system (reaction) the reaction will occur or shift in the direction that will counteract this change. This is a process known to chemists as Le Chatelier鈥檚 Principle and can be illustrated by the following analogy that I learnt at school. Let鈥檚 say two friends, Bob and Leo, are playing volleyball. They begin to play normally which we will call their equilibrium state. All of the sudden, someone watching them play decides to join Bob鈥檚 team. Leo now has to adjust how he is going to play to be able to keep up with his opponents so he will begin to test out different positionings on the court until he finds the best one that lets him get back into the groove of play. Now they are back in equilibrium but Leo had to change something about how he was playing.聽A similar thing happens when not enough CO₂聽is in the blood because if we look at reaction 1, we see that a decrease in CO₂聽will shift the equilibrium position so that this change will be counteracted. If we don鈥檛 have enough CO₂ we want to produce more so the backwards (left) reaction will be favoured. This however consumes the carbonic acid (H₂CO₃) that we also require for normal functioning which in turn has its effect on equation 2. Since we now have less H₂CO₃聽 we want to try and make up for it so the equilibrium position in equation 2 will shift to the left as well in an attempt to product more carbonic acid. This shift will actually decrease the amount of bicarbonate and hydrogen ions in the blood which has a significant effect on the body. More specifically, the loss of the hydrogen ions (H+) causes a change in the pH of the blood. Very simply, pH is the measure of acidity and basicity of a substance and blood has to have a very specific pH which is around 7.35-7.45. Even a small alteration of this value can have detrimental effects to the body and can even cause death. The hydrogen ions are notably acidic so when we lose them, the body鈥檚 pH increases (more basic) which is a condition called alkalosis and this is exactly what hyperventilation does. We have less carbon dioxide in the body, our body tried to counteract the change but in doing so we lose some our precious acid that helps our body maintain this magic pH number. So why do you think we tell people to breathe into a bag?

Why a bag?

I am sure you could have guessed that to solve the alkalosis problem we just need to bring CO₂聽levels back up and a very efficient way to do this is by using a paper bag. When continuously inhaling and exhaling into a bag, we are replenishing our CO₂聽stores. The bag becomes very concentrated with carbon dioxide so that when we breathe in the body鈥檚 normal equilibrium positions can be re-established, and the body鈥檚 pH can go back to normal. So even though you are breathing in hot and humid air from that bag, you are ultimately restoring your body鈥檚 required balance and are saving yourself for some unpleasant symptoms.

So, there you have it, hyperventilation is a very intricate chemical process which can usually be solved with something as simple as a paper bag. Let鈥檚 just hope that if ever you need to use this trick, you brushed your teeth that morning and that the bag you are using wasn鈥檛 holding someone鈥檚 pungent lunch鈥�

@AngelinaLapalme

Angelina Lapalme is a BSc student majoring in Bio-Organic Chemistry at 91社区.聽

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