Q4 Caffeine Flashcards
Mechanism/ Theory
Reaction to caffeine is dependant on two genotypes
- CYP1A2 AA: enhanced ergogenic effect
- CYP1A2 CC: reduced ergogenic effect
- ADORA2A TT: enhanced ergogenic effect + increased anxiety
- ADORA2A C: reduced ergogenic effect + reduced sleep quality
CYP1A2 encodes for the enzymes responsible for caffeine metabolism
ADORA2A gene encodes for adenosine receptors in the brain
Adenosine is a CNS depressant, caffeine is an adenosine antagonist, so reduces fatigue
Main effects are on CNS
Actions
Nervous system: improves focus and energy, reduces tiredness
Hormones: adrenaline
Fat burning: increases lipolysis
endorphins: increases endorphins
Body temp: increases thermogenesis
Glycogen: caffeine can spare muscle glycogen due to increased fat burning
Dosage/ Timing
Doses between 3-6mg per kg have ergogenic effect on endurance performance
Consumed between 30 and 60 mins prior to exercise
Adjust dose according to genotype
Non-genotype factors
- gender
- other medication
- habituation
- training status
- method of delivery (Anhydrous caffeine supplements appear to be most beneficial)
Positive Circumstances
Study on runners showed an increase in power output of 1% which equalled a 15% improvement in time to exhaustion
Works most effectively in well trained athletes
Good for glycogen sparing
Good central effects
Readily available and safe to use
Negative Circumstances
Large individual variation due to different genotypes
Classified as an addictive substance and get withdrawals (headaches, muscle aches, central fatigue
Chronic high doses associated with decreased calcium absorption of calcium (osteoporosis)
Can also cause:
- Headaches
- GIT disturbances
- Anxiety
- Sleeping difficulties
- Increased blood pressure
CYP1A2 AA
enhanced ergogenic effect
CYP1A2 CC
reduced ergogenic effect
ADORA2A TT
enhanced ergogenic effect + increased anxiety
ADORA2A C
reduced ergogenic effect + reduced sleep quality
