Exercise Flashcards
What happens to you when you exercise?
Some of your muscles contract more frequently than normal so you need more energy. This energy comes from increased respiration. The increase in respiration in your cells means you need to get more oxygen into them. Your breathing rate and breath volume increase to get more oxygen into the blood, and your heart rate increases to get this oxygenated blood around the body faster. This removes CO2 more quickly at the same time. When you do vigorous exercise your body can’t supply oxygen to your muscles quickly enough, so they start respiring anaerobically.
Why is respiring anaerobically not the best way to transfer energy from glucose when you do really vigorous exercise?
Lactic acid builds up in the muscles, which gets painful. (lactic acid is formed from the incomplete oxidation of glucose).
What do long periods of exercise cause? Why is this a problem?
Long periods of exercise cause muscle fatigue - the muscles get tired and then stop contracting efficiently.
What is the term called that you’ll have after resorting to anaerobic respiration when you stop exercising?
An “oxygen debt”.
What is oxygen debt?
The amount of extra oxygen your body needs to react with the build-up of lactic acid and remove it from the cells. Oxygen reacts with the lactic acid to form harmless CO2 and water.
How does your body deal and respond to oxygen debt?
You have to “repay” the oxygen that you didn’t get to your muscles in time because your lungs, heart and blood couldn’t keep up with the demand earlier on.
This means you have to keep breathing hard for a while after you stop, to get more oxygen into your blood, which is transported to the muscle cells. The pulse and breathing rate stay high whilst there are high levels of lactic acid and CO2. Your body also has another way of coping with the high level of lactic acid - the blood that enters your muscles transports the lactic acid to the liver. In the liver, the lactic acid is converted back to glucose.
