A little science around caffeine

In the menus I send you, I recommend coffee or a dose of caffeine before a workout, especially in diets.

So, let's take a look at the science behind caffeine, which will actually answer why I write caffeine or coffee into the diets in the first place. You'll also learn why coffee doesn't get you high anymore and how to improve it.

Do you remember what you felt after your first cup of coffee? A remarkable ability to concentrate, maybe even a little euphoria. Compare that to the feelings that follow your multiple cups this morning. Not much, huh? Coffee just doesn't get you as pumped up as it used to. So what's happened since that first coffee that was so magical?

CAFFEINE TOLERANCE.
Caffeine is found mainly in tea and coffee. It is the most popular stimulant in the world. It can cause anxiety in some people, but we usually associate a cup of coffee with happiness and for some of us even relief. Unfortunately, only people who are not used to caffeine will experience the truly euphoric effects of caffeine. Chances are, if you're a coffee lover like me, you'll only experience a small caffeine awakening.This is because just one coffee a day is enough to increase your caffeine tolerance. And before we get to the second cup, remember that caffeine tolerance is an insurmountable tolerance. This means that at some point, caffeine just stops working. To maximize the benefits of caffeine, you can try to skip caffeine occasionally. It's not easy though, I for one can't imagine a day without coffee.

HOW IT WORKS
Caffeine can block various adenosine receptors in the brain with different effects. By blocking the A1 receptors, which when activated promote fatigue, sleep and drowsiness, caffeine can increase alertness. By blocking A2A receptors, caffeine can increase dopamine levels, which has stimulatory and mood-enhancing effects.
A1 receptors are not desensitized, which may be why caffeine does not lose its wakefulness effect. However, A2A receptors do become desensitized, which is why veteran coffee drinkers don't feel true stimulation even after drinking several cups.

THE BENEFITS OF CAFFEINE
For many of us, making a hot cup of coffee or tea in the morning has become almost instinctive. It's not only about enjoying the great taste, but it also helps us kick-start the day, perhaps after a bad night's sleep. What some people don't know, however, is that coffee brings other great benefits:

1.CAFFEINE CAN BOOST PERFORMANCE
A caffeine dose of 400-600 mg is one of the most reliable and effective ways to temporarily increase strength through supplementation. People who rarely consume caffeine usually experience better performance during anaerobic exercise.
Caffeine can also play a role in post-workout recovery, whether you're a caffeine novice or not. In fact, ingesting caffeine along with carbohydrates can improve glycogen replenishment, which is especially important if you train very frequently or several times a day. Here's the contradiction though, I also found an article where coffee after training is not advisable because the adrenal glands start producing cortisol after drinking it. Cortisol is indeed a stimulating hormone, but it is also catabolic, so you can prolong the catabolic state after a workout that is created by exercise. Personally I never give coffee after a workout, for me it's great before a workout, in the morning or during the day.

2.CAFFEINE CAN HELP BURN FAT
Two distinct effects contribute to why caffeine helps burn fat: a thermogenic effect (in the short term, caffeine increases heat production) and a weaker lipolytic effect (caffeine causes the release of triglyceride fatty acids, which the body can then use as fuel).
Specifically, caffeine can increase the level of cyclic adenosine monophosphate (cAMP) in the body. Increased cAMP levels are associated with lower triglyceride levels in fat cells and improved protein synthesis in muscle cells.

GET MORE BENEFITS FROM CAFFEINE
How to maximize the benefits of caffeine? Simply not using it often . It can be difficult, but limiting your caffeine intake to once or twice a week is the best way to get more benefits from each cup.

Source.