Dietary supplements (year 2) Flashcards

1
Q

Caffeine?

A
  • C8H10N4O2
  • Trimethylxanthine
  • Natural vs. Synthetic
  • Found in seeds, nuts and leaves
  • Rapid absorption
  • Peak plasma 30-60 min
  • Half-life 3-5 hours
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2
Q

Adenosine?

A
  • C10H13N5O4
  • Regulated by ATP metabolism
  • Backbone of ATP
  • increase during muscular work and during sleep
  • decrease in brain during wakefulness
  • ATP breakdown = Adenosine
  • Similar chemical structure to caffeine…
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3
Q

Adenosine effects

A
  • ‘Modulates’ release of most brain neurotransmitters such as:
  • Dopamine
  • Serotonin
  • Acetylcholine
  • Norepinephrine
  • This results in:
  • decreased arousal •increased sleepiness •decreased spontaneous motor activity
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4
Q

Adenosine Receptor Antagonism

A

•CNS stimulation•
increase Excitatory neurotransmitter release

  • Caffeine
  • Potent adenosine antagonist (opposing)
  • Can also cross blood brain barrier

•Adenosine Receptors
•Located throughout the body:•
4 types
•A1, A2A, A2B, A3

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5
Q

Increased lipolysis

A

•A2A receptor has additional roles: Inhibit phosphodiesterase (PDE)
= ↑ in cyclic AMP (cAMP)

Sym. Nervous System (SNS)↑ Adrenaline (CA or NA)

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6
Q

Calcium handling?

A
  • Calcium mobilisation •increase capacity for muscle contraction
  • Caffeine reduces the threshold for ryanodine receptors
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7
Q

Summary of caffeine’s effect on endurance performance?

A
  • increase time to exhaustion (20 -50%)
  • decrease fatigue
  • increase performance (middle and long-distance)
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8
Q

Beetroot (nitrate)

A

to get Nitro oxide you need to have enough L-citrulline which leads to L-arginine plus oxygen to allow for nitro oxide (natrual)

using beetroot shots to increase Nitrate to nitrite to nitro oxide after reduction.

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9
Q

What does Nitrate Allow?

A

reduces energy cost of sprinting and allows the athlete to reach the steady state quicker with less energy needed.

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10
Q

what dose has the largest effect?

A

8.4 mmol nitrate has the largest time until exhaustion.

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11
Q

Mechanisms of nitrate?

A

vasodilates the blood vessels, more o2 supply

allows for reduced use of ATP, more ATP available.

ATP / Oxygen ratio(mitochondrial efficiency)

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