Central Fatigue Flashcards
True/False: Afferent feedback is an important mechanism in central fatigue
True, feedback from fatigued muscles sends signals which can influence the ability to maintain muscle performance
Which of the following is NOT a key neurotransmitter in the regulation of Central Fatigue?
- Serotonin
- Adrenaline
- Dopamine
- Adenosine
- Adrenaline, it is an important neurotransmitter but hasn’t been associated with central fatigue
True/False: Dopamine synthesis and metabolism increase with exercise
True
Which of the following may central fatigue result from?
- Reduced force or ability to sustain the required power over time
- Reduced motor output
- Increased serotonin synthesis, reduced dopamine synthesis, hypoglycaemia and hyperthermia
- Increased serotonin synthesis, increased dopamine synthesis, hyperglycaemia and hyperthermia
- Increased serotonin synthesis, reduced dopamine synthesis, hypoglycaemia and hyperthermia
True/False: Caffeine supplementation increases exercise tolerance by reducing central, not peripheral fatigue
False, caffeine acts both centrally and peripherally.
How does caffeine act centrally?
Enhances dopamine release, which is critical in motivation/reward, pleasure and motor control/coordination.
During exercise how does extra fatty acid help build dopamine and serotonin?
Fatty acids cause tryptophan to be released from albumin. Supplementing (BCAA), less tryptophan crosses the blood brain barrier
True/False: Glucose is involved in both central and peripheral fatigue
True, glucose is a fuel that muscles rely on. A lack of affects peripherally, the brain is also dependent on glucose so it also affects centrally.
What is central fatigue related to?
Reduced neural output of central structures
What is the central governor model (CGM)?
It predicts that neural control systems in the brain and spinal cord establish the number of motor units activated in the muscle to ensure homeostasis is maintained
What is central fatigue?
Force decline caused by a reduction in the moroneuron firing frequency, caused by reduced excitatory drive from the brain
What is the role Noradrenaline?
NA
- Implicated in regulation of attention, arousal and sleep cycles
- Learning and memory
- Anxiety, pain & mood
What is does too much Serotonin lead to?
5-HT
Tiredness and lethargy
Why do we want more dopamine?
To increase motivation, reward & attention
What happened to the rats when injected with the 5-HT agonist compared to the 5-HT antagonist?
Agonist - Mimics 5-HT, Antagonist - Counteract the effect of 5-HT
The endurance time was less than the control for the agonist, and longer for the antagonist
What mechanism separates the brain & spinal cord from the rest of the body?
Blood-brain barrier
At rest, is there a high or low ratio of free Typtophan compared to branched chain amino acids?
Low
True/False: If there is a greater ratio of BCAA to f-Trp in the blood then a similar ratio will be transported to the brain
True, they use the same transport mechanism so the ratio is kept similar
What is an essential building block of Serotonin?
Tryptophan
Why is there more f-Trp during exercise than at rest?
The Trp is originally binded to the albumin however as there are more FFA, they bind to the albumin and kick the Trp off
What happens to the ratio of f-Trp to BCAA during exercise?
It increases as some of the BCAA can be used to generate energy
Why is more serotonin produced during exercise than at rest?
As there is a much larger ratio of Trp to BCAA, a lot more Trp will travel through to the brain than BCAA so more serotonin will be produced
What is the aim of BCAA supplementation?
To reduce the amount of serotonin produced during exercise by decreasing the ratio of f-Trp to BCAA by increasing the amount of BCAA
What happened in the rat trial when they were given Amphetamines to try increase brain dopamine activity?
Up to a certain dose, the endurance time increase however anymore than this dose would have a negative affect on the endurance time
