Jan Roscoe Publications OCR A Level Examinations Physical

Jan Roscoe Publications OCR A Level Examinations Physical Education Advanced GCE A 2 7875 A 2 Unit G 453 Principles and Concepts across different areas of Physical Education Option B - Scientific Options Option B 3 - Exercise and sport physiology H - Health components of fitness Body composition - Obesity

Body composition - obesity INDEX A 2 Physical Education unit G 453 3 - WHY IS BODY COMPOSITION SO IMPORTANT? 5 - OPTIMAL BODY MASS 6 - OBESITY 8 - ENERGY BALANCE 11 - HEALTH IMPLICATIONS OF OBESITY CHD 13 - HEALTH IMPLICATIONS OF OBESITY TYPE 2 DIABETES 16 - HEALTH IMPLICATIONS OF OBESITY TYPE 2 DIABETES MANAGEMENT 18 - HEALTH IMPLICATIONS OF OBESITY METABOLIC SYNDROME 20 - HEALTH IMPLICATIONS OF OBESITY TEMPERATURE CONTROL 22 - EXERCISE AND OBESITY 23 - WEIGHT LOSS PLAN index previous next Section B Option B 3 H: Exercise and Sport Physiology 2

Body composition - obesity A 2 Physical Education unit G 453 WHY IS BODY COMPOSITION SO IMPORTANT? the table below shows how the body fat content for people of various age groups depends on whether they are fit or not age group relative body fat (%) untrained females trained males 15 -19 20 -29 30 -39 20 -24 22 -25 24 -30 7 -13 6 -12 8 -14 index previous 13 -16 15 -20 18 -26 next 12 -20 10 -18 12 -20 Section B Option B 3 H: Exercise and Sport Physiology 3

Body composition - obesity A 2 Physical Education unit G 453 WHY IS BODY COMPOSITION SO IMPORTANT? from the table on the previous slide: – the average body fat for untrained females is about 8% higher than untrained males – trained females are exceptionally lean and their relative body fat values are well below those values for untrained males – therefore females can reduce fat stores well below what is considered normal for their age – untrained males and females have increased body fat when they get older, whereas trained people (both sexes) remain lean index previous next Section B Option B 3 H: Exercise and Sport Physiology 4

Body composition - obesity A 2 Physical Education unit G 453 OPTIMAL BODY MASS achievement of optimal body mass requires manipulation of the energy balance when energy input and output are balanced: energy input = energy output a person’s body mass will be stable, and adipose tissue (fat) will neither increase nor reduce hence a diet which matches energy output is necessary to maximise performance index previous next Section B Option B 3 H: Exercise and Sport Physiology 5

Body composition - obesity A 2 Physical Education unit G 453 OBESITY OVERWEIGHT “a body weight that exceeds the norm or standard weight for a particular height frame size gender” OBESITY “a surplus of adipose tissue resulting from excessive energy intake relative to energy expenditure” males - body fat greater than 25% females - body fat greater than 35% index previous next Section B Option B 3 H: Exercise and Sport Physiology 6

Body composition - obesity A 2 Physical Education unit G 453 OBESITY index previous next Section B Option B 3 H: Exercise and Sport Physiology 7

Body composition - obesity A 2 Physical Education unit G 453 ENERGY BALANCE CAUSE OF OBESITY the main cause of obesity is a positive energy balance ENERGY INTAKE > ENERGY OUTPUT or more food than exercise excess carbohydrate (CHO) is stored as glycogen when glycogen stores are filled, CHO together with excess fat intake, is converted to fatty acids and glycerol, and then is stored as triglycerides or fat in adipose tissue situated around major organs such as the heart and stomach, underneath the skin, and in skeletal muscle upper body obesity poses a significantly greater risk to disease health conditions such as coronary heart disease, diabetes and hypertension with an increased risk of mortality and morbidity index previous next Section B Option B 3 H: Exercise and Sport Physiology 8

Body composition - obesity A 2 Physical Education unit G 453 ENERGY BALANCE CONTROLLING OBESITY the only method of controlling obesity is to shift the energy relationship so that energy output exceeds energy intake known as a negative energy balance and expressed as: – ENERGY OUTPUT > ENERGY INTAKE a negative energy balance can be achieved with the help of a Weight Loss Plan index previous next Section B Option B 3 H: Exercise and Sport Physiology 9

Body composition - obesity A 2 Physical Education unit G 453 ENERGY BALANCE WHAT IS A GOOD LEVEL OF FAT? a minimum requirement which would allow full body functions body fat percentage for men is between 2% and 3% and for women between 8% and 12% normally only healthy elite athletes attain these percentages relative body fat is a major concern of sportspeople achieving a desired weight goal can lead to clinical eating disorders such as anorexia nervosa caused by a person restricting food intake to levels well below energy expenditure it is important to have a diet that maintains appropriate weight and body composition to maximise physical performance index previous next Section B Option B 3 H: Exercise and Sport Physiology 10

Body composition - obesity A 2 Physical Education unit G 453 HEALTH IMPLICATIONS OF OBESITY CORONARY HEART DISEASE - CHD obese people have a high risk factor of developing coronary heart disease (CHD) CHD is one of Britain’s greatest killers and encompasses conditions such as angina / heart attacks / coronary thrombosis angina begins as a chest pain, which is due to ischemia is a condition in which there is a reduction in flow of blood and hence oxygen to the heart muscle itself index previous next Section B Option B 3 H: Exercise and Sport Physiology 11

Body composition - obesity A 2 Physical Education unit G 453 HEALTH IMPLICATIONS OF OBESITY CORONARY HEART DISEASE - CHD the first symptoms of CHD are usually noticed during physical exertion or excitement and the subsequent increase in heart rate angina is normally treated and controlled with drugs and relaxation, but a person suffering from this condition has a higher risk of suffering from a coronary thrombosis health risks from CHD can be reduced by regular aerobic exercise this helps to maintain good coronary circulation (blood flow in the heart muscle itself), and strengthens and improves cardiac function index previous next Section B Option B 3 H: Exercise and Sport Physiology 12

Body composition - obesity A 2 Physical Education unit G 453 HEALTH IMPLICATIONS OF OBESITY TYPE 2 DIABETES diabetes is a condition which occurs when a person’s body cannot regulate glucose levels glucose is regulated by the release of the hormone insulin from the Isles of Langerhans situated in the pancreas too much glucose present in the bloodstream causes more insulin to be released to help remove it obesity is a major risk factor for type 2 diabetes index previous next Section B Option B 3 H: Exercise and Sport Physiology 13

Body composition - obesity A 2 Physical Education unit G 453 HEALTH IMPLICATIONS OF OBESITY TYPE 2 DIABETES if not enough glucose is present, the insulin available is reduced, and glucose levels are allowed to build up the insulin enables the transfer of glucose from the blood into cells where it is needed for metabolism type 2 diabetes usually occurs in older people and is caused by age-related changes in the way the body reacts to insulin production obesity is a major risk factor for type 2 diabetes index previous next Section B Option B 3 H: Exercise and Sport Physiology 14

Body composition - obesity A 2 Physical Education unit G 453 HEALTH IMPLICATIONS OF OBESITY TYPE 2 DIABETES obesity is a major risk factor for type 2 diabetes symptoms of type 2 diabetes are: · lack of circulation to the hands and feet · extremes of thirst or hunger · unexplained weight loss · partial or total sight loss regular aerobic exercise improves the regulation of blood glucose levels in the blood of type 2 diabetes sufferers index previous next Section B Option B 3 H: Exercise and Sport Physiology 15

Body composition - obesity A 2 Physical Education unit G 453 HEALTH IMPLICATIONS OF OBESITY TYPE 2 DIABETES MANAGEMENT if exercise is continued through middle-age and oldage (from 40 onwards), blood glucose is broken down and hence the proportion of glucose carried by blood is reduced and the chances of type 2 diabetes reduced muscle cell walls in people with type 2 diabetes become less permeable to glucose needed for exercise therefore normal levels of insulin can’t transfer blood glucose into the cells for metabolism this is insulin resistance index previous next Section B Option B 3 H: Exercise and Sport Physiology 16

Body composition - obesity A 2 Physical Education unit G 453 HEALTH IMPLICATIONS OF OBESITY TYPE 2 DIABETES MANAGEMENT but during exercise, muscle contraction increases cell membrane permeability to glucose which means glucose can pass naturally into the cells this in turn means that cell requirement for insulin is reduced (called insulin sensitivity) this means that acute bouts of exercise reduce the effects of type 2 diabetes index previous next Section B Option B 3 H: Exercise and Sport Physiology 17

Body composition - obesity A 2 Physical Education unit G 453 HEALTH IMPLICATIONS OF OBESITY METABOLIC SYNDROME metabolic syndrome is a term used to link coronary artery disease, hypertension, abnormal blood lipids (fats), type 2 diabetes and abdominal obesity to insulin resistance the syndrome refers to the fact that some people develop a resistance of their muscle cells to the action of insulin and therefore not enough glucose finds its way into the cells to enable them to work properly thus making type 2 diabetes worse hence cells (particularly muscle cells) will not have enough glucose to function properly - and the person feels exhausted index previous next Section B Option B 3 H: Exercise and Sport Physiology 18

Body composition - obesity A 2 Physical Education unit G 453 HEALTH IMPLICATIONS OF OBESITY METABOLIC SYNDROME the · · · risk factors for metabolic syndrome are: arterial plaque build-up excessive fat deposits in the abdominal region / obesity high blood triglycerides, low HDL cholesterol and high LDL cholesterol · raised blood pressure (hypertension) this syndrome brings a higher risk of circulation and eyesight problems in older people index previous next Section B Option B 3 H: Exercise and Sport Physiology 19

Body composition - obesity A 2 Physical Education unit G 453 HEALTH IMPLICATIONS OF OBESITY TEMPERATURE CONTROL obese people have difficulty in regulating heat loss and hence body temperature this is because of the excess adipose tissue layer under the skin this layer in effect acts as an insulating barrier to heat conduction from the body core to the skin where it would be radiated off to the surroundings, or lost by convection and evaporation index previous next Section B Option B 3 H: Exercise and Sport Physiology 20

Body composition - obesity A 2 Physical Education unit G 453 HEALTH IMPLICATIONS OF OBESITY TEMPERATURE CONTROL therefore, when exercising, an obese person would become unduly hot and uncomfortable and require extra cooling methods such as ice packs or cold drinks conversely, the same layer helps keep obese people warm in winter! index previous next Section B Option B 3 H: Exercise and Sport Physiology 21

Body composition - obesity A 2 Physical Education unit G 453 EXERCISE AND OBESITY EXERCISE exercise reduces obesity by burning off excess fat during and after activity when the body’s metabolic rate remains elevated cardiac workload (hence risk of CHD) is less with a lower body mass the capability to move around (walk, run and climb) is therefore better with a lower body mass this is because a person’s strength to weight ratio will become less as he / she becomes lighter exercise relieves symptoms of osteoarthritis as flexibility of joints improves index previous next Section B Option B 3 H: Exercise and Sport Physiology 22

Body composition - obesity A 2 Physical Education unit G 453 WEIGHT LOSS PLAN index previous next Section B Option B 3 H: Exercise and Sport Physiology 23