Week 10 - Caffeine

Question 1

What are the effects of caffeine ingestion?

Answer 1

Improved vigilance and alertness
Reduced perception of effort
Reduced fatigue and pain
= All lead to improved performance

Question 2

Explain the muscle ion effect on how caffeine works

Answer 2

Caffeine increases the release of intramuscular calcium ions responsible for muscle contractions, although this seems to happen with very high doses of caffeine

Question 3

Explain the metabolic effect of how caffeine works

Answer 3

Caffeine stimulates lypolysis (breakdown of triglycerdies), directly and via an increase in adrenaline. This may spare muscle glycogen

Question 4

Explain the central effect on how caffeine works

Answer 4

Caffeine has similar chemical structure to adenosine which is responsible for the feeling of tiredness and pain. Therefore caffeine can stop adenosine from binding to its receptors in the brain reducing the sensations of both tiredness and pain

Question 5

Sources of caffeine

Answer 5

Tea and coffee are good sources of caffeine but the actual caffeine content varies. For exact caffeine content, batch tested supplements are recommended

Question 6

What is an advantage of using caffeinated gum?

Answer 6

Most of the caffeine bypasses the gut which leads to increased absorption and decreased gastrointestinal distress.

Question 7

What are the optimal doses for enhancing athletic performance

Answer 7

3mg/kg BM (same as optimal dose for enhancing cognitive function)
Larger amounts do not seem to provide an extra benefit and may only increase the side effects

Question 8

When should the caffeine be ingested?

Answer 8

Usually 40-60 mins before the exercise
Throughout the event at lower doses (1.5mg/kg)
Late during the event or before an important stage of the event (100-200mg)

Question 9

Explain how co-ingestion can be effective

Answer 9

Co-ingestion with CHO is ergogenic and offers greater performance improvements than CHO alone (70% improvement due to caffeine). Ingesting caffeine in drinks contributes to hydration

Question 10

When should caffeine be used?

Answer 10

Endurance sports - >60 min
Brief sustained high-intensity sports (1-60 min)
Team and intermittent sports - work rates, skills and concentration
Single efforts involving strength or power

Answer 11

Genetics can impact caffeine recommendations each individual responds differently

Question 12

How can caffeine impact sleep

Answer 12

Sleep - caffeine can effect sleep onset and quality - this may interefere with an athlete’s recovery between training sessions. The timing of intake should be considered.

Question 13

How can caffeine impact hydration

Answer 13

Small to moderate doses of caffeine have minimal effects on urine losses and overall hydration. Drinks containing caffeine contribute to fluid intake

Question 14

What are some other side effects of caffeine

Answer 14

1. At moderate and high doses >6-9 mg/kg other side effects such as anxiety, jitters, insomnia, inability to focus
2. There is a dependency to caffeine - anxiety and sleep disorders, withdrawal effects can occur

Question 15

Is caffeine considered a safe compound for consumption

Answer 15

Yes it is especially when low to moderate doses are ingested. These doses are
commonly defined as: ≤400 mg/day from all sources and ≤200mg at any one time

Question 16

How dangerous can excessive caffeine intake be

Answer 16

Excessive caffeine intake has been linked with many health issues. Highly concentrated or pure caffeine can be lethal and WADA continue to monitor patterns of misuse

Question 17

Is there a greater risk of caffeine for children

Answer 17

Use of caffeine by children carries greater risk. Children <18 years are suggested to limit caffeine intake to <2.5 mg/kg/day.