two ways to measure energy utilisation
direct calorimetry (heat production) and indirect calorimetry (resp. gas exchange).
what do we assume for EE from gas exchange
a given small amount and constant amount of protein oxidation, we are working in..
how do we get EE from gas exchange
measure both VO2 and VCO2 to know how much cho and fat use.
kj/ LO2 for diff foods
carb - 21.1
protein - 19.25
fat - 19.81
alcohol - 20.40
mixed diet - 20.22
RER for protein
0.8
average daily energy use gold standard
“doubly labeled” water (stable isotopes)
how does double labeled water work? look into this
uses rate of water excretion to indicate energy metabolism through stable isotopes. using the excretion rate of the water to calculate co2 production and with assumed or measured RER to calculate EE
advantages and limitations of double labeled water
?
what are the effects of exercise on RMR
Increased 5-15% with intensive ex. for 24-48 h. if ex is repeated w/in 24-48 h remains elevated.
what are the chronic affects of exercise on RMR mainly due to
increase in FFM which needs more energy.
do endurance trained adapt to use less energy
they may have an increased efficiency of movement but it is not a large effect on TEE, most trained, in training use more energy regardless.
study on elite Kenyan runners
they seemed to have an increased energy expenditure to energy intake. this may have advantageous, economy and reduced heat retention (less fat). but they may have less fuel storage as they are not having enough energy intake BUT this may be overcome by having an extremely dense CHO diet
study on training indivduals EE
sleeping in the first 7 weeks were using more EE then went back down to normal or still slighty higher, free living they were had a lower EE so more economical during rest, at training they were using more energy.
what age group does increase in PA no increase TEE
older, also not if diet restricted
how can increase in substrate usage and amounts stored affect both performance and health
increase amount of fat at moderate then you can save carb for longer.
health - increasing glucose uptake into muscle reduces blood glucose levels and can enhance glycogen storage.
what influences which fuels we use when?
training status, duration, intensity, availability, adrenaline.
what influences our fuel selection?
energy needed for the task, amount of fuel already in the circulation or storage, contraction (calcium), enzyme acitivity, hormones (SNS - noradrenaline, adrenaline and insulin), aeorbic capacity and blood flow, and transport molecules.
how does the muscle know what it needs?
energy charge over the cell, we have indicators telling us what is going on of the energetic state, whether there is ATP there ot not. what is acculumulating around e.g. atp broken down creates adp, then amp, and then phosphate comes from it.
phosphagen (ATP-CP), anaerobic glycolysis, aerobic cho system and fat system. max power, max capacity and o2 requirementrs
on your ipad that drawing / table. fat has the highest o2 requiremet and highest capacity but lowest power.
anaerobic glycolysis system information, max power, max capacity and o2 requirement
max power 2.4 moles of ATP/min
max capacity 1.6 moles of ATP
o2 requirement 0 mmol o2/atp
aerobic cho system information, max power, max capacity and o2 requirement
max power 1.0 moles of ATP/min
max capacity 84 moles of ATP
o2 requirement 0.167 mmol o2/atp
fat system information, max power, max capacity and o2 requirement
max power 0.4 moles of ATP/min
max capacity 4000 moles of ATP
o2 requirement 0.177 mmol o2/atp
differences between fat and cho
cho is used both anaerobically and aerocbically, cho has a more limited storage, creates less atp/sec but needs less o2 per atp.
difference in cho and fat metabolism with exercise
fat increases w exercise duration whereas cho increases with intensity. when we train fat usage increases at any given intensity whereas cho decreases.
