Know Your Tools - Caffeine
Looking to understand how caffeine increases workout performance? You’ve come to the right place!
In the literature, it has shown slight improvements in muscular strength, power & endurance, with the greatest outcomes on muscular endurance. These ergogenic effects occur with doses ranging from 2-9 mg/kg, with the sweet spot dose at 5-6 mg/kg. Larger doses tend to increase anxiety, jitteriness and GI distress with very little extra benefit. With chronic caffeine consumption, it appears that our bodies build tolerance, lessening its ergogenic effects overtime. Most habitual stimulant users end up requiring a baseline dose to feel “normal” and a much greater dose to derive its ergogenic effects.
Its performance benefits are derived primarily through its influence on the Central Nervous System (CNS) and several peripheral mechanisms.
In the CNS, caffeine attaches to adenosine receptors (primarily receptors A1 & A2A) , blocking the uptake of adenosine. In the CNS, adenosine is what makes us feel fatigued among several other things. Caffeine's interaction with the adenosine receptor also positively influences one's perception of pain.
Peripherally, there are increases in catecholamine production (adrenaline & noradrenaline) which increases cardiac output and fat and glucose metabolism. Our sympathetic nervous system goes into overdrive, allowing us to be better prepared for the strenuous work to come.
Additionally, in muscle tissue, there’s a greater release of calcium from the sarcoplasmic reticulum, leading to stronger & longer sustained muscle contractions.
Many other mechanisms have been proposed, but these are the big hitters. By taking caffeine we delay fatigue, decrease subjective pain, increase alertness & enhance motor unit firing which can increase performance.
As habitual caffeine consumption appears to decrease caffeine's ergogenic effects, I would advise using caffeine supplementation only 1-2 times per week on your most taxing training days. By doing this, you won’t need as much to derive positive benefits (somewhere in that 1-3mg/kg range). Additionally, you’ll avoid many of the negative consequences of chronic stimulant use such as sleep disturbances, behavioural changes (anxiousness, hyper-vigilance) and dependency. Being in a state of hyper-vigilance interferes with your ability to recover, as your body is stuck in a chronic state of fight or flight. In general, this is a state that we want to be in during exercise but not outside of the gym.
In all, caffeine can be an amazing drug when used correctly. Based on its abilities to decrease fatigue, decrease perceptions of pain, increase cardiac output and enhance muscle contractions, this compound can have tremendous benefits in glycolytic based workouts that contain short rest intervals, uncomfortable sets, and high heart and ventilation rates. If you’re a coffee lover and coffee isn’t something that you want to give up, consider going with decaffeinated coffee as an alternative on days when you’re not training. This way you’ll still be deriving the host of positive health benefits associated with coffee consumption.
