42 Cleveden Road, Glasgow G12 0JW

0141 582 0060

Cleveden Secondary School


Caffeine & Energy Drinks




What is it?

Caffeine is a drug that stimulates (increases the activity of) your brain and nervous system


What does caffeine do to your body?

Caffeine is easily absorbed by the body.  The short-term effects are usually experienced between 5 and 30 minutes after consumption.  Some common effects are increased breathing and hear rate, increased mental alertness and increased physical energy.  Depending on the individual, these effects can last up to 12 hours.


Other effects of caffeine can be:

  • Increased body temperature
  • Dehydration
  • Increased urination
  • Dizziness
  • Headaches
  • Palpitations
  • restlessness
  • excitability
  • anxiety
  • irritability
  • sleeplessness
  • tiredness


Where is it found?

Caffeine naturally occurs in plants such as tea, coffee and cocoa (therefore found in chocolate) and is also added to energy drinks, and some other substances such as painkillers. It can temporarily ward off drowsiness and restore alertness, and is so widespread we rarely think of it as a drug.


How much caffeine is okay each day?

The effects of caffeine depends on a variety of factors, such as, a person’s mass, their health and their metabolism.  Also, a person’s experience (if someone is used to regular doses of caffeine) and how much he/she has in one serving.  However, a recommendation of 400mg or less is an acceptable dose.

Approximate caffeine levels per serve include:

  • instant coffee (80-120mg per 250ml)
  • filter coffee (150 – 240mg per 250ml)
  • espresso coffee or latte (105 -110mg per 250ml)
  • decaffeinated coffee (2–6mg per 250ml)
  • tea (65 – 105mg per 250ml)
  • chocolate drinks (5 – 10ml per 250ml)
  • cola drinks (40 – 49mg per 375ml)
  • Red Bull energy drink (80mg per 250ml)
  • Energy drinks (160mg per 500ml)
  • Milk chocolate bar (10mg per 50g)
  • Dark chocolate bar (40-50mg per 55g)