How Does Caffeine Enhance Exercise Performance?

Caffeine is a very potent substance that can boost mental and physical performance.

A dose of caffeine can boost your performance during physical activities, as well as fat burning and focus (1, 2, 3, 4).

Caffeine is so potent that it is used even by the United Special Forces to boost performance and awareness.

Caffeine is a major ingredient in many beverages and foods, and at least 90% of Americans consume it regularly (5).

This article will explain in detail how caffeine enhances exercise performance.

How does caffeine work?

Caffeine has a fast rate of absorption. This means that its levels in your bloodstream peak very fast – let’s say 90-100 minutes after taking it. Also, it remains at high levels for at least 3 hours, before it starts to drop (6, 7).

Compared to other supplements and substances, caffeine affects different body cells, including the brain and the muscle (6).

Because of this, the effects of caffeine on the body are quite varied. Common effects include:

  • Activating the nervous system: Caffeine activates some areas of the nervous system and the brain thus improving energy and focus (6, 8).
  • Hormones: Adrenaline, also known as epinephrine is the key hormone behind the body’s “fight or flight” response. This response increases exercise performance (3).
  • Burning of fat: Caffeine boosts the body’s fat-burning ability. This occurs via a process called lipolysis. Lipolysis means “breakdown of fat cells” (3).
  • Endorphins: β-endorphins make you feel better, and “high.” It is responsible for the high feeling that people experience after they’ve exercised (9, 10).
  • Muscles: Caffeine influences the activities of the motor cortex. The motor cortex is a component of the brain that signals muscle activation (11).
  • Body temperature: Studies have shown that caffeine increases heat production, whose technical name is thermogenesis. Thermogenesis increases the number of calories burnt by the body (12).
  • Glycogen: Caffeine has a “sparing effect” on muscle carb stores, mainly due to increased fat burning. This boosts performance during exercise (13).

The liver is the site of caffeine breakdown (6).

Does caffeine help with endurance?

Many athletes are huge fans of caffeine. I’d say it’s their “go-to supplement.”

Because of its positive effects on exercise performance, NCAA and other organizations have begun to ban it in high doses.

A particular study found that 400mg of caffeine (4.45 mg/kg, or 9.8 mg/lb.) increased endurance in athletes.

The athletes in this study were able to run at least 1.3 miles ahead of athletes in the placebo group (14).

Another study involving cyclists found that caffeine was better than water or carbs. It caused a 7.4% increase in workload, compared to the carb group which had a 5.2% increased workload (15).

Another study found that the combination of carbs and caffeine improved exercise performance by 9% compared to just water, and 4.6% compared to just carbs (16).

Coffee is naturally high in caffeine. A study on a 1500-meter race found that athletes who drank coffee regularly ran 4.2 seconds faster than those who drank decaf. In another study, coffee helped the athletes to feel less-stressed, thus enabling them to work harder (17, 18).

How does caffeine influence high-intensity exercises?

There are mixed pieces of evidence regarding the effects of caffeine on high-intensity exercises.

It is worth knowing that caffeine has great benefits for trained athletes. However, its benefits for untrained or amateur athletes are not that much.

Studies involving recreationally-active men engaged in bike sprints found no difference between the effects of water and caffeine (19, 20).

In the case of competitive athletes, a bike sprint associated caffeine with a significant improvement in power (21).

Another study examined the effects of caffeine on untrained and trained swimmers. In the study, significant improvements were found in the trained group, but none were observed in the untrained group (22).

With regards to team sports, caffeine supplements caused a significant improvement in passing accuracy in rugby, as well as soccer sprint times and performances in 500-meter rowing (23, 24, 25).

Caffeine and strength exercises

Studies are ongoing on the effects of caffeine on power-based or strength exercises.

A couple of studies have found positive effects. However, these are not conclusive (26).

A particular study found that caffeine had positive effects on the bench press but had no significant effect on cycling sprints or lower body strength (27, 28).

A review of 27 studies found that caffeine had the potential to boost leg muscle power by at least 7% but didn’t have any effects on smaller muscles (26).

What’s more? Caffeine also improves muscular endurance, including the number of repetitions done at a particular weight (26).

Summarily, the research shows that caffeine improves performance in power-based activities involving large muscles, circuits, or repetitions.

Does caffeine contribute to fat loss?

Caffeine is a primary ingredient in weight loss supplements. Studies have shown that caffeine when taken before exercise boosts fat burning by 30% (1).

A second study found that supplements containing caffeine caused the fast release of fat storage before a workout and after a workout (29).

Caffeine can also boost the amount of fat burnt during exercise. What’s more? It increases epinephrine and heat production, which in turn burns extra fat and calories (3, 12).

Presently, though, there is no proof that caffeine promotes long-term weight loss in physically-active individuals.

The best way to supplement with caffeine

You have to consider a couple of things when supplementing with caffeine.

If you’re a fan of energy drinks, coffee, dark chocolate, or soda, then you may not benefit much from supplements. Why? Because your body can tolerate caffeine (30).

Anhydrous caffeine is very beneficial for exercise performance, but then, coffee is also great. Coffee is loaded with antioxidants and tons of health benefits (13).

Your recommended dose is based on your body weight, usually set at 1.4-2.7 mg/lb. of body weight. For most people, that’s 200-400 mg. Some studies, however, use 600-900 mg (31).

You must start now – let’s say 150-200 mg. Doing so will help you to assess your tolerance. You can then increase the dose gradually – 400-600 mg may be, so you can maintain the benefit.

If you want to use it during athletic events, then you must save it for races or key events. Doing so will maintain its sensitivity.

For best performance, coffee is best taken 60 minutes before an event. You must give this a test trial before main use, especially if you’re not used to taking caffeine.

What are the side effects of caffeine?

When taken at a reasonable dose, caffeine can furnish your body with many benefits, but very few side effects. But then, it may not be recommended for some people.

Excess caffeine is associated with the following side effects:

  • Anxiety
  • Increased heart rate
  • Dizziness
  • Tremors
  • Irritability
  • Stomach discomfort
  • Sleep disruption or insomnia