Anaerobic Threshold Flashcards
What is the anaerobic threshold?
Point at which anaerobic respiration has to supplement the aerobic system
Why does lactate accumulate with increasing work rate?
Accelerating glycolysis,
lactate removal slows,
Increased fast twitch fibre recruitment
What are the uses of lactate?
Cori cycle for gluconeogenesis,
Shuttled to heart and brain,
Oxidised in high oxidative muscle fibres of working muscles,
Oxidised in muscles with lower metabolic cost
Why is lactate metabolism important?
It’s a major energy source, the major gluconeogenic precursor and a signalling molecule.
What is the lactate shuttle?
The autocrine, paracrine and endocrine link between glycolytic and oxidative metabolism.
give some examples of why lactate and ventilatorY threshold are not interchangeable?
McArdles syndrome - sufferers experience sever muscle pain during exercise and hyperventilate,
Glycogen depletion,
Caffeine
Describe minute ventilation at Low work rates
It is strictly proportional to the work rate
What happens to minute ventilation above the ventilatory threshold?
Minute ventilation exceeds these proportionality’s and there is extra ventilation in excess of VO2 to remove CO2
Explain isocapnic buffering
A region where the lactic acid being produced is being buffered by HCO3, which generates the excess CO2. At higher work rates, lactic acid production overwhelms blood buffers and the pH declines, causing extra ventilation further - causing rise in Ve/Vco2 ratio
