Energy Systems Flashcards
What is the difference between aerobic and anaerobic respiration?
aerobic is with oxygen and used for long term steady paced exercise and day to day activities.
anaerobic is without oxygen and produces fast bursts of energy for short powerful bursts.
Describe aerobic respiration
- produces the largest amounts of energy but at lowest intensity
- can be broken down into: glycolysis, Kreb’s cycle, Electron Transport Chain (ETC)
What process is used at the beginning of exercise and why?
Anaerobic processes. Because at the start of exercise, the body cannot deliver oxygen to the muscles fast enough to initiate aerobic metabolism.
Describe alactic (ATP-PC) anaerobic respiration
- The breakdown of ATP produces energy and ADP.
- The increase of ADP triggers an enzyme called creatine kinase to initiate breakdown of phosphocreatine (PC) into phosphate and creatine.
- Only have 120g of creatine, so repeated breakdown of PC to produce energy to resynthesize ATP is temporary and can only last max. 10 seconds
Describe lactic anaerobic respiration
- aka anaerobic glycolysis, because initial process is the same as aerobic glycolysis but without oxygen
- due to lactic acid production, this energy system can only be predominant for up to 2 minutes
- even if the metabolic process did not require oxygen, after anaerobic exercise, the body will be in oxygen debt=high respiration rate
Name 3 responses to stimuli
- neuromuscular
- anaerobic
- aerobic
Describe anaerobic responses to stimuli
- stored ATP used for first 2 seconds
- ATP broken down, ADP triggers creatine kinase to breakdown PC
- ATP-PC (anaerobic alactic) system can only be used for 8-10 seconds before PC stores are depleted
- After 10 seconds, the anaerobic lactic system takes over as predominant source of energy production. High intensity, sub maximal exercise can last 3-5 mins.
- If exercise continues at a high intensity so oxygen is not available quick enough for aerobic metabolism to take over, the production of lactic acid will eventually interfere with muscle function… lactate threshold
When do muscles begin to fatigue?
when ATP resynthesis can no longer match demand
Describe aerobic responses to stimuli
- after first few minutes of exercise are completed with anaerobic metabolism, continued low to moderate intensity exercise is fuelled by carbohydrate and fat stores using aerobic metabolism
- intensity and duration of exercise determines which fuel source is used (ex. fat metabolism is a slow process and can only be used for exercise at less than 60% VO2 max, while carb metabolism can be used for exercise up to 80% VO2 max)
- carb stores within muscle and liver can fuel exercise for up to 80 minutes. As carb stores get lower, the body relies more on fat stores, and intensity of maintained exercise drops
Define VO2 max
measure of the peak volume of oxygen (VO2) you can consume and use in a minute. Measured in ml/kg/min …relative to body weight. Peak of oxygen utilization
Can VO2 max be trained?
yes. Adaptations to cardiovascular, respiratory, muscular systems which make processes of gas exchange, oxygen transport, and aerobic metabolism more efficient.
What happens when exercise is continued past the peak of oxygen utilization?
- anaerobic energy systems must be used
- produces lactic acid, causes fatigue, therefore cannot be sustained
- causes oxygen debt
When does oxygen debt occur?
when you have a short intense burst of exercise you generate energy for it anaerobically.
What does EPOC stand for and what is it?
Excess Post-exercise Oxygen Consumption.
When you stop short intense exercise, your body needs more oxygen to recover than your body would have liked to use had enough been available.
Increased rate of oxygen intake to erase oxygen deficit
What happens during EPOC?
- breathing rate and HR increase to remove CO2 and get more oxygen
- body temperature and metabolic rate are increased which demands more oxygen
- adrenaline and noradrenaline are increased which increases oxygen consumption
