Caffeine

Question 1

Caffeine

Answer 1

1,3,7-trimethylxanthine –> metabolised in liver
common drug
removed from WADA list
coffee, green tea, chocolate, coca-cola

Question 2

Bioavailability caffeine

Answer 2

peak blood caffeine conc = 60 mins after ingestion in dose-dependent way
benefits can occur soon after intake before reach peak blood conc

interacts with all body cells
crosses blood-brain barrier

Question 3

Effects caffeine

Answer 3

improved vigilance and alertness
reduced perception of effort
reduced fatigue and pain
= improved performance

Question 4

Central effect

Answer 4

blocking adenosine
caffeine stop adenosine from binding to its receptors in the brain
due to similar structure
= reduce sensation of tiredness and pain
delay fatigue
improve alertness and reaction time

Question 5

Metabolic effect

Answer 5

increase fat mobilisation and oxidation
caffeine directly lipolysis (increase triglycerides breakdown)
indirectly (increase epinephrine/adrenaline) stimulate fat metabolism
high doses
spare muscle glycogen

Question 6

Muscle ion effect

Answer 6

increase in calcium release in muscle
caffeine increases release of intramuscular calcium ions (Ca2+) reposnible for muscle contractions
high doses
supplementation = increase muscle force generation

Question 7

Caffeine adition

Answer 7

no effect on fat or carb metabolism
but still beneficial to performance - GLU + CAF = 4.6% better

Question 8

Caffeine gum

Answer 8

caffeine bypasses gut
= increase absorption faster
decrease GI distress

Question 9

Optimal caffeine amount

Answer 9

3 mg/kg BM

Question 10

Caffeine timing

Answer 10

~40 to 60 mins before exercise/event
throughout event at lower doses (~1.5 mg/kg)
late during event/before important stage of event

Question 11

Habituation

Answer 11

caffeine supplementation resulted in improved strength endurance and jumping performance
independent of habitual caffein consumption

Question 12

Caffeine coingestion

Answer 12

CAF + CHO = ergogenic
taken in energy drinks = reach hydration goal

Question 13

Caffeine supplementation sources

Answer 13

coffee
capsules
gum
gel
sports drinks

Question 14

Caffeine use

Answer 14

endurance sports >60 min
brief sustained high-intensity sports 1-60 min
team sports
single efforts strength/power
pre-training energy boost

Question 15

Caffeine genetics

Answer 15

self-experimentation and practice in training
individual variability

Question 16

Caffeine risks: sleep

Answer 16

can affect sleep onset/quality
interfere with athlete’s recovery between training sessions/during multi-day comps
timing = ~5 hours half to leave bloodstream

Question 17

Caffeine risks: hydration

Answer 17

small/moderate doses = minimal effect on urine losses in habitual caffeine users
caffeine-containing drinks (tea, coffee, coca-cola) = contribute to fluid intake

Question 18

Caffeine side effects

Answer 18

doses >6-9 mg/kg = anxiety, jitters, insomnia, inability to focus, GI unrest, irritability
dependency
anxiety, sleep disorders, withdrawl effect

Question 19

Caffeine safety issue

Answer 19

low to moderate doses = safe
<400 mg/day and <200 mg at one time
less during pregnancy
excessive intake = unsafe
children <18 years = limit caffeine intake <2.5 mg/kg/day
batch-tested supplements only

Question 20

Caffeine recommendations

Answer 20

ergogenic effects = supported by scientific research
not on WADAs prohibit list
evidence caffeine can enhance performance
high doses = neg side effects
safe but individual variability