This method is accurate, but does have its limitations. It cannot be used for anyone who is ill, anyone whose health is frail, or anyone who cannot hold breath for a determined period of time and it cannot be used for children.
Biolelectric impedance analysis
This method measures body composition by sending a low, safe electrical current
through the body. The current passes through the fluids contained in muscle tissue but finds it difficult to pass through fat. This resistance of the fat tissue to the current is termed 'bioelectrical impedance', and is accurately measured by body fat scales. When set against a person's height, gender and weight, the scales can then compute their body fat percentage.
This method is easy fast and inexpensive but can be inaccurate if the body is dehydrated or the bladder is empty
Energy Expenditure
Direct or indirect calorimetry is used to find the rate of energy expenditure from the body
Direct Calorimetry
This is when a person sits in a specialised airtight container with a certain amount of water in at a certain temperature. The water absorbs the heat that comes from the person and this data is recorded and used to find out how much energy was used and therefore how many calories were required.
Indirect Calorimetry
This focuses on the oxygen uptake especially after aerobic exercise and is more accurate than the direct calorimetry
Closed circuit spirometry – the person breathes in pure oxygen from a spirometer
Open circuit spirometry is when energy expenditure is measure during exercise when the person is breathing a mixture of oxygen carbon dioxide and nitrogen. It is calculated by the percentage changes in oxygen and carbon dioxide of air that is breathed out along with the volume of air breathed over a certain amount of time.
The amount of activity that goes into energy expenditure includes all movement, from sitting in a chair to running on a . It is expressed as physical activity level (PAL); someone who works in an office and sits down a lot of the time, will have a lower PAL than someone who does manual work or who exercises on a regular basis. Daily energy expenditure, as measured in calories burned, can be increased by simply moving more through the day like walking to work instead of driving.
Watching your BMI helps you to maintain the right weight and also the right proportion of bone density and muscle and to reduce the fat content in case it is high. There are certain risks involved if your body mass index is on the high side or even if it is too low.
Looking at my own body composition at 182cm and weighing 67kg mu body mass index works out as 20.2 which is healthy. This is due to the fact that although my diet is high in fat, I take part in lots of exercise which keeps my body fat at a low level, However in order to improve my overall fitness and health I need to alter my diet so that I am healthy inside too, My calorie intake is quite high but I need these calories because of my height and to give me the energy for all the exercise I do.
P4/M2/D1
Energy Balance
Our energy balance is the balance of calories taken in through eating and drinking compared to how many calories we use by being physically active. A certain amount of calories are used simply by breathing air and digesting food and just during your daily routine, for example walking to the bus stop, going to the shops etc.. People who are more physically active burn more calories than those who are not as physically active. If you take in the same amount of calories as you burn off your weight will remain the same, If you take in more calories than you burn off then you will gain weight and if your take in less calories than you burn off you will lose weight over time.
Your energy in and energy out do not have to balance every day, you will stay at a healthy weight if you have a balance over the long term. It is important that children balance their energy but it should be considered that they are growing and that energy in and energy out supports natural growth without encouraging weight gain
Resting metabolic rate (RMR)
This is influenced by body composition, age, gender and genetic predisposition. Muscle is more metabolically active than fat so an increase in muscle mass produces and increase in RMR.
Thermic effect of feeding
This is due to the effects of digestion, absorption and metabolism of food, largely influenced by the calorific value of the food especially the ratio of fat and carbs. It is easier for the body to take on body fat from dietary fat than form dietary carbs. On average it is 10% of energy expenditure
Thermic effect of activity
This is the effect of energy used on activity so has implications for sportsmen and women and depends on the type of activity and the duration. On average it is 20% of energy expenditure.
Adoptive Thermogenesis
This is a response to changes in temperature and physiological stresses. On average it is 10% of energy expenditure
Factors that affect energy expenditure
- How often you exercise
- Intensity of exercise
- How long the exercise lasts for
- Type of exercise
- Age, gender, body composition
- Climate
To work out the energy value of a food , you need to find the number of grams of carbohydrates and then multiply this by the number of kilocalories per gram then you do the same for protein and fat, Then you add up the total number of calories to get the energy value of the food. For example if the kilocalories per gram for the food was carbohydrate 4, Proten 4 and Fat 9 then the energy value of one slice of wholemeal bread with 80g of beans would be 4, then the carbohydrate was 14 x 4 = 56, protein was 6 x 4 = 24 Fat was 1 x 9 =9
Then 56 + 24 + 9 = 89
Personal energy requirement = basic energy requirements + extra energy requirements
Basic energy requirements (BER) includes your basal metabolic rate (BMR) and general daily activities
- For every Kg of body weight 1.3 Calories is required every hour. (An athlete weighing 50Kg would require 1.3 × 24hrs × 50Kg = 1560 Calories/day)
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For a calculation of your BMR, see the calculator on the page
Extra energy requirements (EER)
- For each hours training you require an additional 8.5 Calories for each Kg of body weight. (For a two hour training session our 50Kg athlete would require 8.5 × 2hrs × 50Kg = 850 Calories)
An athlete weighing 50Kg who trains for two hours would require an intake of approximately 2410 Calories
Like a car needs fuel to go, we need energy and the ideal blend we need is
- 57% Carbohydrates (sugar, sweets, bread, cakes)
- 30% Fats (dairy products, oil)
- 13% Protein (eggs, milk, meat, poultry, fish)
An athlete weighing 50kg taking in 2410 calories per day will need 57% of carbohydrates = 57% of 2410 = 1374 calories at 4 calories/gram = 1374 divided by 4 = 343 grams. Fats 30% of 2410 = 723 calories at 9 calories/gram = 723 divided by 9 = 80. Proteins 13% od 2410 = 313 calories at 4 calories/gram = 313 divided by 4 = 78 gramsCarbohydrates - 57% of 2410 = 1374 Calories - at 4 Calories/gram = 1374 ÷ 4 = 343 grams
So he needs 343 grams of carbohydrates, 80 grams of fat and 78 grams of protein
Runners will require more energy than gymnasts because of the nature of the sport and the height and weight of the runner in comparison to the gymnast
Looking at my own energy requirements over 5 days not including calories burnt breathing during my daily routine
Total Energy Output = 5534
I then looked at my average input in a week using my 5 day diet plan
Total Energy Input 8669 not including fruit and drinks
Values for my metabolic rate are 68kg x 23 = 1564
Basic metabolic Rate + Activity Expenditure = Total Output =
1564 + 5534 = 7980
Energy input (calories from food) = Total Input = 8669
My input is higher than my activity expenditure but \i have not included my day to day calories burnt from just breathing and going about my daily routine which if taken into account would bring my activity expenditure higher than my calorie intake. But because I have a high fat content in my diet, my weight stays the same.
Assignment 3 - Hydration
The human body consists of 65% water, the body need water to function correctly. Every healthy person should aim to drink at least two litres of water a day. This is to keep your body temperature at 37 degrees and exercise increases your body temperature.
Fluid loss
Sweat is one of the most common ways of loosing sweat along with urine. Sweat is not just water that is released through the skin it is also salt, electrolytes, sodium and potassium. Losing fluid can increase heart rate, raise the body temperature and even energy product affect that results in premature fatigue and an impaired sports performance. Loss of fluid can involve in viscosity of the blood.
Your sweat loss varies in what sport you are performing in, for example the table below.
You can have varied effects on loosing sweat from the body
Urine checks
Your urine colour is a distinctive accurate way of checking your hydration, the lighter the colour of the urine the more hydrated you are and the less hydrated you are the darker the colour of the urine.
Energy drinks
There are three different types of energy drinks which deferentiate in levels of energy push. The three different types are
Isotonic – Fluid, electrolytes and 6 to 8% of carbohydrates, this type of energy drink would be taken to do light sources of exercise that only gives you a slight awakening for example to wake the brain to do darts to help concentration.
Hypertonic – fluid, electrolytes and low level of carbohydrates, this type of energy drink would be drank when playing a medium level of exercise for example 90 minutes of football or 80 minutes of rugby.
Hypertonic – high levels of carbohydrates, this would be drank if you were about to take on a high expectancy of the muscles for example a extreme exercise drill or a marathon.
