Energy Answers Units 1 - 3

1. Energy Answers Units 1 - 3 Energy, Fitness, The Kilojoule and You Energy and Aerobics The Anaerobic Threshold

2. Energy, Fitnessm The Kilojoule and You • The more you exercise the more the body will adapt by increasing its ability to produce energy to meet the demand. The opposite is true as well. The less active you are, your body adapts by losing its ability to produce energy. A fit person feels like they have pep and zip because their body is able to easily produce energy. • The relationship of body weight to energy consumption is that the bigger heavier person will use more energy than a smaller lighter person doing the same activity. A 75 kg person will consume 101 kj of energy during one hour of sleep compared to 81 kj consumed by a 60kg person sleeping the same amount of time. 3. Calories are measures of energy in our bodies and a kj is a metric measure of energy in our bodies. 1 calorie = about 4.2 kj. One carrot contains about 105 kj while a piece of pie yields as much as 1470kj. The average person will burn 1 Calorie by doing about 8 - 10 jumping jacks.

3. Calories An interesting fact is that a calorie is the amount of energy required to raise the temperature of 1 kg of water 1 degree Celcious..

4. Two Energy Systems Aerobic vs Anaerobic • The body uses two different systems to produce energy – Aerobic (with Oxygen) and Anaerobic (without Oxygen) • Anaerobic system produces quick energy for intense activity for short durations (less than one minute). It does not require Oxygen but will produce lactic acid waste. A buildup of lactic acid around the muscle interfers with the muscle function and results in rapid muscle fatigue • Aerobic system produces high levels of energy for continuous, moderate levels of activity for long periods (ie – jogging). It requires Oxygen, does not produce lactic acid waste or cause quick muscle fatigue. It produces much more energy than the anerobic system can allowing for longer duration exercise.

5. Energy and Aerobics • One KG of body fat can propel an average person about 180km. In order to burn 20 kj (5CAL) of energy it will take 1 liter of Oxygen. • A minimum of 15 minutes of aerobic activity is required to achieve a training effect and have an improvement in our CV fitness. • Aerobic capacity is the amount of Oxygen your heart and lungs can deliver to the muscles in one minute. A fit person can deliver more than an unfit person. As CV fitness improves the heart increases in size and can pump more blood in one beat (Stroke Volume). The resting heart rate lowers as the heart does not have to beat as fast to deliver the same quantity of blood • Target Heart Zone (THZ) refers to the intensity range one has to get their heart rate in during exercise to achieve a training effect and to improve CV fitness. It is calculated by the formula of: 220 – age times 80% for the upper limit and 220 – age times 60% for the lower limit. If you don’t reach the THZ during the exercise you will burn calories but not get an improvement on your CV fitness. • If you exceed the THZ then you would tire out quickly.

6. The Anaerobic Threshold What is anaerobic threshold? • When you are exercising aerobically such as a 10 k run and you increase the intensity beyond your ability to produce energy aerobically (ie – you sprint at the end) your body is forced to produce the extra energy anaerobically The level where you stop producing energy aerobically and begin anaerobic production is called the Anaerobic threshold. Muscle Fatigue will set in quickly (due to lactic acid buildup) once the anaerbobicthrehold is entered Someone who is very fit aerobically will have a higher threshold than someone who is less fit. • The “Talk Test” is when jogging you are able to carry on a conversation and keep up the exercise comfortably. If you are able to carry on a conversation while running it means you are not exceeding your anaerobic threshold.

7. Anaerobic Threshold can be seen when the HR goes above the working Target Heart Zone. The energy demand exceeds the hearts ability to supply oxygenated blood to the muscles. Energy begins to be produced anaerobically. Exhaustion soon follows.Check the marathon runner below. What minute does he hit his threshold???