Effects of energy intake and expenditure on performance

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Task 1

Energy Intake is the amount of energy you take in during a certain period e.g. the recommended daily energy intake for men is 2500 kcal and for women is 2000 kcal. This energy is then expended during exercise or any physical activity.

Energy is needed for respiration- breathing, keeping your heart beating, keeping the body warm and all other bodily functions needed for survival. It is also needed for physical activity with relation to muscle contraction. Finally energy is needed for growth and repair of body tissue.

Metabolism is the rate at which chemical reactions occur within the body to keep the body health and in working order. Basal metabolic rate is the minimum level of energy intake needed to keep essential bodily functions working and to keep our organs and tissues in working order. Resting metabolic rate is all the energy you have used in a day other than that for physical activity.

The higher the level of activity, then the more energy is burnt off. E.g. if an average adult male weighing 155 pounds plays badminton for 30 minutes they will burn off approximately 205 calories where as if the same person performs kickboxing for 20 minutes they will burn off 372 calories. As the level of activity increases so does the energy expenditure. The length of time you perform an activity can also affect the amount of energy you expend. For example, a marathon runner or an Olympic rower will burn off far more calories than say someone who was playing social badminton for 30 minutes etc.; this is because the intensity is higher but so is the period of time. Because athletes perform at high levels of intensity and time in sport each day their body is working harder to respire, this means the heart is beating faster to become accustomed to this increased requirements. Bodily heat increases whilst athletes are performing because the muscles are contracting and relaxing faster; this is why you can sometimes see steam come off athletes during cold weather. Also, when athletes are performing, they may be working harder than what their muscles are accustomed to; this means that muscle tissue tears and the body will make sure it repairs these tissues to ensure they can cope with this increased level of activity- this is how muscles grow and become stronger. If you have been working in the gym for an hour etc. then you are burning more calories at a higher rate than someone sitting on the sofa watching TV. However, if you go home after this hour and sit down on the sofa your body will still burn calories at a higher metabolic rate because your metabolism stays raised for several hours. Depending on the intensity at which you have worked your body’s metabolism will stay high for longer.

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There are a several factors effecting energy intake and expenditure, I’ve already stated about activity levels and time but there are also things such as: somebody with more muscle mass will need more energy intake to cope for this higher mass- athletes have as a whole have a bigger muscle mass than the average person so they will need more energy to cope with this higher muscle mass. Climate can also affect the amount of energy needed- the higher the temperature the more energy needed to maintain body temperature, the body has to work harder in high temperatures because ...

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