How Caffeine can boost your Workout

Nothing delivers a bigger kick in the pants before a workout than caffeine. It’s no wonder that caffeinated pills and drinks are the most common supplement category among bodybuilders, athletes, and gym-goers. Study after study has shown that caffeine can increase alertness, sharpen focus, improve mood, improve tolerance for pain caused by exercise, help burn fat, and help athletes do more work for longer periods in the gym and in sport.

Here’s what the science says about how the world’s most popular stimulant can help your training.


Where does caffeine come from?


Coffee beans are best-known for their caffeine content, but not all beans are created equal in this regard. An average Arabica bean contains about two milligrams of the stimulant, compared to nearly three milligrams in each Robusta bean.

The type of the beans used and the strength of the brew determine exactly how much caffeine is in a cup. The average cup of filtered coffee contains about 85 milligrams, it’s 65mg for instant coffee, and there is about 60mg of caffeine in a small espresso shot. Even “decaffeinated coffee” contains about three milligrams of caffeine.

In short, while there are no important nutrients in coffee, it contains bountiful amounts of caffeine.


There’s caffeine in brewed tea, too – but why? The compound occurs naturally in Camellia sinensis, the tea plant which is the source of black tea, green tea and white tea. Black tea contains the most caffeine because it comes from oxidized tea leaves, but still only about half the amount found in brewed coffee. The longer you steep tea, though, more caffeine will end up in your cup.


There’s caffeine in most types of chocolate, but it’s not enough to wake you up in the morning or keep you awake at night. Cacao beans contain only about five percent of the amount of caffeine in coffee beans; chocolate will add to your daily total caffeine consumption, but the sugar and calories in chocolate are more of a concern than its stimulant effect. 

Dark chocolate contains 2-3 times more caffeine than milk chocolate, and the darker the chocolate, the more caffeine it has. 

Soft Drinks and Energy Drinks

It’s pretty well-known that Sprite and ginger ale aren’t caffeinated, but Coca-Cola and many other carbonated beverages (mostly the cola-style ones) are. Are they made from a plant that contains caffeine, too?

Not exactly. Once upon a time, kola nut extract was used to produce Coke and similar colas, and as you’ve certainly guessed, kola nuts contain caffeine. The extract hasn’t been used for some time, though. 

Then where does the caffeine come from? Actually, it’s an added ingredient in soda – supposedly there to provide added taste, although at least one study has shown that it doesn’t do that at all. When the Food and Drug Administration (FDA) proposed a rule banning caffeine in soda 40 years ago, the soft drink industry insisted that caffeine was a crucial additive. They claimed that the bitterness of caffeine was needed to balance the soda’s sweetness. And it’s still there today.

Caffeinated drinks like Coke and Pepsi have caffeine levels about half that of coffee, about 35-40 milligrams of caffeine per can, which is why a Coke doesn’t get you as “juiced” as coffee. Mountain Dew contains about 55mg, and energy drinks like Red Bull come in well over 100mg of caffeine. 

Synthetic caffeine is the primary stimulant ingredient in energy drinks, although some also contain the extract of guarana berries, which do contain natural caffeine. (Synthetic caffeine is also added to many over-the-counter headache medications, because it’s been found to amplify the meds’ effectiveness.)

Natural and synthetic caffeine are chemically identical, but the body absorbs the synthetic version faster. That means the energy boost comes more quickly – as does the crash that follows.

How does it affect performance?

Caffeine works on the central nervous system by promoting spinal cord excitability and muscle fiber recruitment, while decreasing perceptions of fatigue and muscle pain. It’s been demonstrated to improve physical performance in all manner of sports while also delaying mental fatigue.

Caffeine can improve performance in a variety of sports and delay fatigue.

Among the benefits it has been shown to provide are:

  • Endurance athletes improved performance by an average of 5 percent.
  • Strength and power sports performance improved up to 20 percent.
  • Sprinters improved performance on average by 8 percent.
  • Weightlifters improved performance on average by 9.5 percent.
  • Rate of perceived exertion (fatigue) is decreased by 6-10 percent on average.

Are there any side effects?

Taking too much caffeine can contribute to anxiety, as most of us discovered in our initial youthful dalliances. However, there are several other considerations you should be aware of.

1. Hydration

Caffeine has been shown to have a slight diuretic effect, which is thought to lead to dehydration, but the effect is marginal. Caffeinated beverages have been shown to hydrate just as well as non-caffeinated beverages. Still, it’s a good idea to increase your consumption of liquids when using caffeine, especially if you train in a hot and humid environment.

2. Addiction

Despite all of caffeine’s health benefits, there’s no denying that it may become habit-forming.

Caffeine triggers certain brain chemicals similar to the way cocaine and amphetamines do, it does not cause classic addiction the way these drugs do.

However, it may lead to psychological or physical dependency, especially at high dosages (>300mg per day).

Symptoms include headaches, anxiety, depression, and cravings. You can alleviate these side effects by weaning off the dosage until the desired amount is reached.

3. Sleep

Some of us metabolize caffeine quickly, while others are slow metabolizers. How dramatically it affects you, and for how long, will vary person by person. If you’re extremely sensitive to caffeine or are prone to anxiety, limit your consumption. 

Caffeine’s ability to help people stay awake is one of its most prized qualities.

On the other hand, too much caffeine can make it difficult to get enough restorative sleep.

Studies have found that higher caffeine intake appears to increase the amount of time it takes to fall asleep. It may also decrease total sleeping time, especially in the elderly.

You may not realize that too much caffeine is interfering with your sleep if you underestimate the amount of caffeine you’re taking in.

What are the most popular sources?

1. Coffee

  • Drip coffee: 60-180 mg per 6 oz.
  • Espresso: 70-80 mg per 1.5 oz.
  • Decaf: 2-5 mg per 6 oz.

2. Canned/bottled coffee drinks

70-180 mg per 8 oz.

Widely available, usually with some protein added in the form of milk, though most have added sugars as well. Also difficult to know exactly how much caffeine you get.

3. Tea

40-80 mg per 5 oz.

Tea is loaded with antioxidants, notably epigallocatechin gallate, or EGCG, which has been shown to have fat-burning capabilities. Caffeine content in teas varies greatly, though black tea typically contains more than green tea.

4. Soft Drinks

40-50 mg per 12 oz.

The caffeine content in soft drinks runs the gamut from insignificant to massive. Unless you opt for a diet version, they’re also usually high in sugar and artificial ingredients.

5. Caffeine capsules

100-200 mg per pill

This is the most affordable and efficient way to take caffeine without having to worry about what else is in it.

The downside: A single pill can leave you jittery if you’ve never tried it before, so start with small dosages.

6. Dark Chocolate

12 mg per oz.

Chocolate contains the potent antioxidant epicatechin among other undeniably healthy ingredients, but it is also usually loaded with sugar. Choose a product with at least 70 percent cocoa, which provides more epicatechin and less sugar.

7. Energy Drinks

75-120 mg per 8 oz.

These are convenient but typically loaded with sugar, unless you choose the sugar-free versions. It’s a relatively expensive way to consume caffeine, too.

10. Green Tea Extract


Though data show that green tea affects metabolism, most manufacturers don’t list the exact caffeine content on this popular fat-burner.

12. Pre-workout Supplements/Fat-burners

150-300 mg

These are convenient and often combined with other pre-workout goodies including creatine, beta-alanine, arginine, and citrulline. You can also mix into your favorite beverage to watch calories.


You can start feeling the effects of caffeine with as little as 20 mg (0.3 mg/kg of bodyweight). If you’ve never used it before, start with the lowest dose and work up accordingly.

The benefits of caffeine appear to be maxed out at around 200 mg (3 mg/kg of bodyweight), with no additional benefits coming at much higher doses. At very high doses (6 mg/kg of bodyweight or 400 mg4) caffeine may start to decrease performance, and increase anxiety and cortisol. You may not think that applies to you, but many people take multiple caffeinated substances without realizing how much total caffeine they ingest.


Caffeine levels in your bloodstream peak approximately 60-90 minutes after consumption. Therefore, you should take it 1-2 hours prior to your training.

Remember that caffeine has a relatively long half-life of about six hours, which means that if you take a 200 mg tablet at 6 p.m., you’ll still have half that amount in your body at midnight. It can affect your sleep cycle if you’re not careful.


Surajit Jana.

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