Energy, metabolism and nutrients (wk1) Flashcards
What are the ATP requirements during exercise?
-> Success in athletic competition is dependent upon the ability to provide energy for muscle contraction. ATP hydrolysis (ATP +H20 -> ADP + Pi + energy)
Describe ATP resynthesis (anaerobic and aerobic) + write down fast and slow resynthesis
ATP resynthesis (to match the rate of utilisation). Anaerobic (fast) and aerobic (slow)
Describe energy systems with power vs capacity
-> Since the intramuscular stores of ATP are small, ATP must be regenerated at a rate sufficient to sustain the level of contractile activity. There is an inverse relationship.
Describe metabolism during sprinting:
-> As exercise intensity increases, the ATP demand cannot be met. There is a decline in the power output, but it is not as steep as the ATP decline – this is because of a greater reliant on aerobic systems which can offset some of the decline, even though in general the power output does drop,
-At exercise intensities that can be sustained for more than a few minutes, most ATP requirements are met through aerobic metabolism
What are the fuels for aerobic metabolism?
Draw the fat, carb and protein metabolism
What is the influence of exercise intensity?
- There’s an increase in muscle glycogen use in 55-75% increase in exercise intensity. This shows how nutrition advice like carbohydrate loading is important when exercising with increased intensity, due to the use of muscle stores used.
What is the influence of exercise duration?
– After 2 hours of exercise, carbohydrate ingestion is needed to maintain blood glucose and carbohydrate oxidation. The longer we go for, the more FFA’s become present.
What are the approximate carbohydrate stores for a 70kg man (blood glucose, liver glycogen and muscle glycogen)
- Blood glucose 3-5g
- Liver glycogen 80-100g
- Muscle glycogen 300-400g
+For approximately 1500-2000kcal (6000-8000 kJ), 1kcal = 4.184kJ
What are the fat stores for a 70kg man (adipose tissues and muscle triglyceride)
- Adipose tissue 3.5-14kg
- Muscle triglyceride 200-500g
+Approximately 31,500-126,000kcal for a 70kg man with a body fat of 5-20%. But fat content can vary considerably.
What are food and nutrients?
-> Food provides nutrients that have physiological and biochemical functions in the body.
Describe nutrients and their classification:
-Nutrients and their classification -> Macronutrients are present in relatively large amounts in the human diet, whereas micronutrients are present in minuscule amounts:
* Macronutrients -> carbohydrate, fat, protein, water
* Micronutrients -> vitamins, minerals, trace elements
What are carbohydrates and name the types of carbohydrates:
-Carbohydrates -> Provides energy – physical activity and central nervous system. Fibre: health benefits. 60% of energy intake.
-Simple (monosaccharides: 1 sugar) -> glucose, fructose and galactose
-Simple (disaccharides: 2 sugars) -> maltose, sucrose and lactose
-Complex (many sugars) -> starch, glycogen and fiber
What are carbohydrate-rich foods?
- Sugars (simple carbohydrates) -> Fruit juices, fruits, sweetened creams, jams, sweets, sports drinks, beet and cane sugar, maple syrup, honey
- Starches -> Cereal, potatoes, pasta, rice, bread
- Fibre -> Whole-grain cereals and breads, oats, fruits and vegetables
What are fats?
-> Energy source. Protection of vital organs. Cell membrane constituents. Precursors of bile, hormones and steroids. Fat-soluble vitamin intake. Palatability. 30% energy intake. Foods high in fat: fatty meats and fish, cheese, butter, avocado, nuts and seeds and chocolate.
Describe the types of fats:
-> Triglycerides are most abundant dietary fat. Fatty acids vary in chain length:
Short chain (SCFA: C6 or less), Medium chain (MCFA: C8-10), Long chain (LCFA: C12 or more). Saturates fatty acids (no double bond) and unsaturated fatty caids (one or more double bond).
What are proteins (amino acids):
-> Proteins provide structure to all cells in the human body. Amino acids have central roles in the metabolism of many organs and tissues. Amino acids are precursors for the synthesis of body proteins. Amino acids are regulators of the synthesis of NTs, hormones, DNA and RNA. Around 10% of energy intake.
Describe protein quality:
-> Complete protein (contain all 9 essential amino acids): fish, poultry, eggs, beef, pork, dairy, whole sources of soy e.g. tofu. Incomplete protein (deficient in one or more essential amino acids): legumes, nuts, seeds, whole grains, vegetables
Name some nonessential and essential amino acids:
-Nonessential -> alanine, arginine, asparagine and serine
-Essential -> Histidine, leucine, lysine and valine
Describe water:
-> Adult body = 60% of water (2/3 found in cells, 1/3 extracellular). Functions – nutrient transport, protection, temperature regulation, biochemical reactions, medium for reactions.
Describe the general dietary guidelines for non-athletes (total fat, saturated fat, cholesterol, total carbohydrate, dietary fibre, sodium, potassium and protein)
How to assess dietary intake:
-> Diet record (3-7 days weighed food intake), 24hour recall, food frequency questionnaire, strengths/ weaknesses with each method, common issues are – compliance/ bias in memory or reporting/ altered behaviour/ underestimating intake
