Dietary supplements (year 2)

Question 1

Caffeine?

Answer 1

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

Question 2

Adenosine?

Answer 2

• 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…

Question 3

Adenosine effects

Answer 3

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

Question 4

Adenosine Receptor Antagonism

Answer 4

•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

Question 5

Increased lipolysis

Answer 5

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

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

Question 6

Calcium handling?

Answer 6

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

Question 7

Summary of caffeine’s effect on endurance performance?

Answer 7

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

Question 8

Beetroot (nitrate)

Answer 8

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.

Question 9

What does Nitrate Allow?

Answer 9

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

Question 10

what dose has the largest effect?

Answer 10

8.4 mmol nitrate has the largest time until exhaustion.

Question 11

Mechanisms of nitrate?

Answer 11

vasodilates the blood vessels, more o2 supply

allows for reduced use of ATP, more ATP available.

ATP / Oxygen ratio(mitochondrial efficiency)