top of page

All About Caffeine

Updated: Apr 3

What is caffeine?

Caffeine is a methylxanthine. Methylxanthines act as adenosine receptor blockers and phosphodiesterase inhibitors.

Adenosine acts as the “brakes” in the central nervous system. So when its effects are blocked (by caffeine), stimulation occurs.

Phosphodiesterase is an enzyme necessary for the breakdown of the 2nd messenger protein cAMP within cells. As its “messenger” moniker implies, cAMP helps transfer signals within cells. If this messenger protein is not being broken down (caffeine prevents this breakdown), it will have a better opportunity to cause its stimulatory effects.

In other words, caffeine prevents the body from slowing things down at a cellular level.

Caffeine can decrease fatigue and increase mental alertness as a result of stimulating the brain.

However, high doses of caffeine can produce anxiety and create a roller coaster of unstable emotions which is super common in today's high functioning, over stimulated society.

What you should know

The good

Caffeine can increase performance, especially with endurance events. Athletes can typically last longer and work harder. But even brief bouts of activity can be improved with caffeine use. This may be due to increased alertness and awareness. Indeed, caffeine can be addictive for many athletes because of these performance benefits.

The bad

Caffeine consumption can decrease the effectiveness of serotonin and trigger the release of dopamine (two major neurotransmitters), which can make it even more addictive.

When someone nixes the caffeine from their daily routine, the adenosine accumulation is substantial, and without the blockade from caffeine, adenosine is free to exert its effects. The over-abundance can cause vasodilation (headaches), shakiness and stomach upset, which are all classic symptoms of caffeine withdrawal.

Because caffeine can affect sleep patterns and the hormones that control appetite, hunger and satiety along with anabolism/catabolism, caffeine can ultimately detract from optimal body composition and performance despite its temporary enhancement.

Caffeine has effects on the gastrointestinal tract. It increases the production of stomach acid, with large amounts inducing stomach upset or acid reflux.

Summary and recommendations

  • The safe upper limit of caffeine is somewhere between 300-400 mg per day depending on your size but that DOESN'T MEAN OPTIMAL.

  • If using caffeine to increase performance, try consuming it 30 to 60 minutes before the event/exercise. Blood levels of caffeine are maximized about 60 minutes after consumption, but effects are noticed by 30 minutes.

  • Try to use caffeine when you actually “need it.” Repeated caffeine consumption can create a tolerance and lessen the benefit.

Site Source: Enzo Nutrition & Precision Nutrition


Recent Posts

See All


bottom of page