Week 10 - Caffeine

Question 1

What is caffeine

Answer 1

1,3,7-trimethylxanthine (metabolised in the liver)

Removed from WADA list 2004

Commonly used drug

Question 2

Describe the bio-availability of caffeine

Answer 2

Peak blood caffeine concentrations typically occur 60mins after ingestion in a dose-dependent manner

Benefits could occur soon after intake

Caffeine interacts with all body cells and crosses the blood-brain barrier

Question 3

What are the effects of caffeine consumption

Answer 3

• Improved vigilance and alertness
• Reduced perception of effort
• Reduced fatigue and pain
  Therefore improved performance

Question 4

What are the proposed mechanisms in how caffeine works

Answer 4

• Muscle ion effect: Caffeine increases the release of intracellular calcium, responsible for muscle contraction
• Metabolic effect: Caffeine increases fat oxidation with possible carbohydrate sparing
• Central effect: - Caffeine can prevent adenosine to bind to its receptors in the CNS, reducing sensations of tiredness and perception of effort (main mechanism)

Question 5

How does the main mechanism of Caffeine work

Answer 5

Caffeine can stop adenosine from binding to its receptors in the brain, reducing the sensations of both tiredness and pain

Question 6

How does caffeine content vary across different sources

Answer 6

The caffeine content varies in different sources and can even vary within the same source depending on how it was prepared

Question 7

What is an advantage to using caffeinated gum

Answer 7

Caffeinated gum can increased absorption and decrease GI distress

Question 8

What is the optimal dose of caffeine when enhancing athletic performance

Answer 8

Optimal dose is 3mg/kg body weight

Question 9

What is the recommended timing for consuming caffeine for an event

Answer 9

40-60mins before event
Throughout the event at lower dosages (1.5/mg/kg)
Late during event or before important stage (100-200mg)

Question 10

What is the effect of caffeine habitual consumption

Answer 10

Caffeine habitual consumption does not affect ergogenic effects, only when high doses are consumed is when performance can be enhanced (6mg/kg/BM)

Question 11

What would make caffeine more effective in performance

Answer 11

Co-ingestion with CHO is ergogenic and offers greater performance improvements than CHO alone. Ingesting caffeine in drinks contributes to hydration as well

Question 12

When should caffeine usage be considered

Answer 12

• Endurance sports (>60mins)
• Brief sustained high-intensity sports (1-60mins)
• Team and intermittent sports
• Single efforts involving strength or power
• Pre-training energy boost

Question 13

What are some risks of caffeine consumption

Answer 13

• Caffeine can affect sleep onset and quality
• Minimal effects on urine losses or overall hydration
• At moderate & high doses, side effects including anxiety, insomnia, inability to focus, GI unrest, irritability
• Dependency to caffeine

Question 14

What are some safety issues and considerations around caffeine consumption

Answer 14

• Caffeine is considered safe to consume in low to moderate doses (<400mg/day) and <200mg at any one time from all sources. (Unless pregnant)
• Pure or highly concentrated caffeine can be potentially lethal
• Children are suggested to limit caffeine intake (<2.5mg/kg/d)
• Athletes should aim to only use batch-tested supplements

Question 15

What are some recommendations to caffeine consumption

Answer 15

• Ergogenic effects of caffeine are supported by scientific research
• Can enhance performance in range of different sports
• High doses can cause negative side effects
• Generally safe to use, although varies across individuals
• Practical considerations before consumption would include dosage, timing, product, event

Question 16

How does the metabolic effect of caffeine work

Answer 16

Caffeine directly increases triglycerides breakdown or indirectly from increasing epinephrine to stimulate fat oxidation

Caffeine could spare muscle glycogen

Question 17

How does the muscle ion effect work in caffeine

Answer 17

Caffeine increases release of intramuscular calcium responsible for muscle contraction

Question 18

What effects does carbohydrate feeding + caffeine have on performance

Answer 18

Greater performance, but no effect of substrate metabolism

Question 19

How does caffeine content vary in different sources

Answer 19

Caffeine derived from any form, can improve performance, but content can vary depending on the preparation mode.

Tea and Coffee have varying contents

Question 20

How can genetics affect caffeine recommendations

Answer 20

Different individuals have genetic variations that react differently to caffeine dosages

Individuals should self-experiment or practice trial and error of caffeine in training to understand optimal dosage and timing