Sleep in endurance sports – Part 5: Sleep and caffeine

Today follows the 5th part of our sleep theme series. We will explain the effects of caffeine on sleep. What exactly does caffeine do to our body? Can we consume as much caffeine as we want? If you have any questions, write to us, and we will answer them in our next Podcast!

What exactly is caffeine?

  • The opponent of adenosine (2)
  • stimulative effect 
  • Effect climax: approx. 30 minutes after ingestion (5)
  • 60 ml espresso = approx. 80 mg caffeine
  • Daily rations of up to 400 milligrams (5.7 mg/kg body weight) Caffeine (6)
  • Contained in: dark chocolate, tea, energy drinks, nuts, cocoa fruits

Caffeine – Metabolism 

  • Degradation in the body: enzymes (Cytochrome P450 1A2) in the liver (5)
  • Degradation time: 5 – 7 hours until approx. 50 % of the caffeine is broken down (1)
  • Reaches the head and brain via the blood
  • Blocks receptors normally occupied by adenosine (5)

Side effects

  • Insomnia 
  • Increased heart rate and higher blood pressure
  • Increased metabolism
  • Irritability 
  • Headaches 

How does caffeine nap work?

  • Drink an espresso before the nap
  • Sleep for a maximum of 30 minutes  
  • During sleep, our brain cleanses itself of adenosine
  • After sleep, fewer adenosine molecules that can attach themselves to receptors
  • Caffeine can develop its full effect (4)

What is best for when I find myself in a lunchtime depression – coffee or a power nap?

We will answer this in our next podcast.


  1. Palmer, A. A., de Wit, H. (2010). Genetics of caffeine consumption and responses to caffeine. Psychopharmacology 311, Nr. 3. 245 – 257.
  2. Horne, J. A., & Reyner, L. A. (1996). Counteracting driver sleepiness: effects of napping, caffeine, and placebo. Psychophysiology, 33(3), 306-309.
  3. Sagaspe, P., Taillard, J., Chaumet, G., Moore, N., Bioulac, B., & Philip, P. (2007). Aging and nocturnal driving: better with coffee or a nap? A randomized study. Sleep, 30(12), 1808-1813.
  4. Reyner, L. A., & Horne, J. A. (1997). Suppression of sleepiness in drivers: combination of caffeine with a short nap. Psychophysiology, 34(6), 721-725.
  5. als chemische Substanz, K. (2016). Die physiologische Wirkung von Koffein. Koffein: Genussmittel oder Suchtmittel?, 39.
  6. Beiglböck, W. (2016). Koffein. Springer Berlin Heidelberg.

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