Energy and Exercise AP BIO

Energy in Humans What sort of activities cause you to use more energy? Lets look at running

Human Body The human body has a limited amount of ATP stored in it The reserve can last about 90 seconds of intense exercise (like sprinting) What does this mean?

Intense Exercise Your body has 3 sources of ATP Stored ATP ATP’s from fermentation ATP’s from cellular respiration The stored ATP will only last about 30-40 seconds After that we begin to undergo lactic acid fermentation

Lactic Acid Fermentation We can use the ATP’s in lactic acid fermentation for about 90 seconds What builds up in our muscles when this happens? Lactic Acid The only way to break down and get rid of lactic acid is by using oxygen

Post Sprint Why do runners breath heavily after a race? Runners breathe heavily after a race to get oxygen to our muscles to break down lactic acid

Running a Mile We have just said that we can only generate ATP with lactic acid fermentation for about 90 seconds. What if you were running a mile?

Long Term Energy Lactic Acid releases energy very quickly (but can only last a short time) When running a mile or more, your body will switch over to cellular respiration (instead of fermentation) Cellular respiration releases energy much more slowly This is why athletes must pace themselves during a race

Energy Sources The body stores energy in a carbohydrate known as glycogen After 15-20 minutes of physical activity, the body will use other sources for energy Fats Proteins