Energy metabolism 2 Flashcards
What is the best way to determine energy requirements in athletes?
Take their weight and diet history, if their weight doesnt change thats their energy requirement
If weight goes up, eating more than needede
If weight goes down, eating less than needed
Define metabolic rate.
Rate at which body expends energy to support vital functions.
Define basal metabolic rate.
Energy needed to maintain life when the body is at complete physical, digestive and emotional rest
Define resting metabolic rate.
Energy expended at any time of day
What are factors that increase BMR
Increased height, increased lean body mass, male, pregnancy, children (growing), fever, external temperature (hot/cold), nicotine, caffeine
What are factors that decrease BMR
Increased age, increased adipose tissue, fasting/starvation, malnutrition, sleep
What are factors that effect RMR
- body composition (obesity) - excess adipose tissue but also fat free mass including muscle = increases RMR
- Age - progessive decline in RMR with age due to decrease in FFM and muscle
- nutritional status - decreased RMR with undernutrition due to loss of FFM and response to conserve energy
What do you need to consider when determining energy requirements?
Athlete - sport, size, gender, level/amount of training, life stage, fitness, psyche, physical health
Environment - Training/competition, duration of event, single or multiple events, terrain, intensity, temperature and humidity, altitude
How does glucose enter the cell?
Muscle contraction and insulin stimulates GLUT-4 which translocates glucose into cardiac, muscle and adipose cells
Muscle activation and release of Ca causes glycogen to breakdown
What energy systems are used in explosive events speed events endurance events ultra endurance events
CrP
anaerobic
aerobic glycolytic
aerobic lipolytic
How does training improve athletic performance?
Increases maximal force, speed, and/or average power output
Increases rate of ATP production from aerobic/anaerobic pathways
Maintain tighter metabolic control (match ATP production with ATP breakdown)
Improve working muscle resistance to fatigue
How does the body adapt to endurance training?
Slower utilisation of muscle glycogen and blood glucose
Increased reliance on fat oxidation
Decreased lactate production
The body uses the energy systems that maximises the most energy for that activity
How does caffeine work as a supplement?
Primary ingredient methylxanthine makes us feel buzzed - reduces perception of effort therefore decreases fatigue = alters perception
When is caffeine useful as a supplement and what is the protocol?
Useful for exercise >1 minute
5-6mg/kg BM (about 300-500mg)
Why is there a variation in response to caffeine?
Due to the CYPIA2*gene = fast metabolisers and slow metabolisers
