I don’t really get this. You inhale oxygen and use it to make ATP through aerobic metabolism (whatever its called).
Why would an unfit person breathe harder? Are they using 2x as much oxygen as a fit person or does the oxygen just not work as efficiently as a fit person’s oxygen? if they are using 2x as much oxygen wouldn’t that mean their metabolism was burning 2x as many calories making being unfit a good thing?
Cuz we’re fatter.
I imagine because a non-fit person’s heart, muscles and lungs are not used to the amount of exertion as a fit person’s body parts are and don’t work as efficently.
When I started jogging last summer, as part of the first attempt I’ve ever made in my life to exercise regularly, it took me about two weeks to realize that I wasn’t breathing correctly. I kept panting while I was running: lots of quick, shallow breaths, and after an embarassingly quick period of time, I’d be completely out of breath. Once I learned to take steady, deep breaths while I was running, I found I had a lot more stamina and could get significantly further before collapsing into a gasping lump. Like, more than a hundred yards.
So, that might be a part of it.
Sort of - with increased cardiovascular/respiratory fitness, the lungs are able to use more of the oxygen inhaled so that person gets short of breath slower.
Actually, thats sounds pretty good. Breathing is very important in exercise.
Consistant cardiovascular stress causes muscle tissue to make more mitochondria, allowing more efficient use of what oxygen they do get. Breathing correctly is important as well.
It also has to do with lung capacity. I’m not a doctor, so someone might correct me on this, but if I recall correctly, lung capacity is somewhat dynamic. The more you use your lungs the better they are at expanding. The more they expand, the more air you can store - the less frequently you have to breathe.
Is this how certain performers are able to hold their breath under water for several minutes?
The unfit person isn’t using oxygen as efficiently and their VO2 max (the rate at which they can use oxygen) is lower. Read here for and exhaustive article on VO2 max and it’s malleability.
Trained atheletes usually have an extremely high VO2 max (Lance Armstrong’s is off the charts) but there’s some debate on whether they become athletes because they had an inherently high VO2 max or if their athletic training increased it. (although the linked article indicates that the ability to increase your VO2max in response to a training program is genetically determined) Boo Boo Foo coudl probably tell us even more…
All very true statments. The muscles of the body use oxygen during “Oxidative Phosphorylation”, where they make ATP from ADP. ATP is used by the muscle cells to bind two cellular components to slide past each other and contract the muscle (Called the ‘Sliding Filament Theory’). Oxygen, as everyone knows, is carried through the blood in Red Blood Cells, on a special molecule called Hemoglobin (Basically a combination of iron and fat). The ratio of red blood cells in a persons blood stream vs other components is called their Hemacrit level (i.e. their ability to transport oxygen). This level of red blood cells can be increased by training at high altitudes (where oxygen levels are low, the body recognizes this and releases a horemone called Erythropoietin, which stimulates red blood cell production in the bone marrow), by ‘blood doping’, or other methods I won’t go into here (normal exercise can increase this level, even if just training at sea level). People who are out of shape, tend to have a much lower Red Blood cell count, and hence their immediate increase in respiratory activity when exercising is in an effort to supply their muscles with more oxygen, as their blood cannot carry as much per breath as a well trained individual. As the body regularly goes into ‘oxygen debt’, the kidney’s release more erythropoietin, and more red blood cells are produced. The lag time between starting exercise, and when you stop breathing rapidly is the amount of time it takes to produce and begin circulating these RBCs.
So as a WAG could a drug like procrit be used to turn people from being out of shape into competent athletes rapidly?
No, the wouldn’t become great athletes, but their ability to efficently use the oxygen they inhale per breath would increase. It is true that, their increased weight requires their muscles to work harder as compared to a person of similar muscle mass (but without the extra weight), and thus requires more oxygen, but the main cause of their increased respiratory rate is the carrying capacity of oxygen in their blood. Increasing the RBC count in their blood (read: Hemocrit levels) will allow them to perform oxidative phosphorylation longer since enough oxygen can be carried to the cells to maintain their output. Once the cellular requirements exceed the oxygen that can be efficently provided, anarobic respiration occurs, releasing lactic acid as a by-product. This increase in lactic acid, and increase in CO2 signals the body to increase the respiratory rate. So to sum: if you can keep your O2 levels high, and your Lactic acid levels low, respiration will occur normally. When CO2 levels get high, or Lactic acid levels rise, respiration increases. Increasing RBC count is a way to combat this, and is indicitave of athletes. Or did I just confuse you more?
You can deliver all the oxygen you want to your muscles, but they can only use so much.
If that were the case, there would be no need to go to anaerobic respiration, which occurs regularly. The requirements for oxidative phosphorylation are simply ADP, Pi and Oxygen. ADP and Pi are always present in the cells, so the only requirement that would be lacking would be oxygen.