A hit of caffeine

Caffeine is a potent drug. So each time you drink tea, coffee, cola or cocoa you are giving your body a ‘hit’ of caffeine. Along with nicotine and alcohol, caffeine is one of the three most widely used mood-affecting drugs in the world.

If you have more than two or three caffeine drinks per day this is likely to be affecting your moods and your physiology – and in a more powerful manner than you might expect.

Caffeine is not harmful – but overuse of caffeine could be.

What is caffeine?

It is a potent and quick-acting drug which produces an effect similar to the stress response in our bodies. Caffeine affects each person differently, depending on individual circumstances such as weight, build, etc. It has an almost instant effect on your mind-body which will continue to influence your state for 6-8 hours afterwards.

Caffeine research

New research into the effects of caffeine continues appear every few months and these reports frequently contradict one another – depending on who did the research, how many people were evaluated and, of course, who funded the research…

So the definitive word on caffeine has not yet been agreed

Caffeine affects each of us differently – a hit of caffeine that will cause insomnia in one person can be a great nightcap for someone else

Take the list below, and the research into caffeine, with a pinch of salt (not literally, of course) and experiment to discover how you, personally, relate with this drug

Reported effects of caffeine

The following effects are commonly attributed to over-use of caffeine – while reading them bear in mind that what is true for one person may not be true for someone else:

  • Stimulates your heart, respiratory system, and central nervous system.
  • Makes your blood more `sludgy’ by raising the level of fatty acids in the blood.
  • Causes messages to be passed along your nervous system more quickly
  • Stimulates blood circulation
  • Raises blood pressure
  • Causes your stomach to produce more acid
  • Irritates the stomach lining
  • Makes digestion less effective by relaxing the muscles of your intestinal system
  • Its diuretic effect caused increased urination  – although you would have have to drink about 8 cups of coffee in one sitting for this to occur! (See 1 below)
  • Stimulates the cortex of your brain heightening the intensity of mental activity. This can result in a temporary feeling of alertness and, in the short term, banishes drowsiness and feelings of fatigue. In those who already have high levels of anxiety the heightened intensity of mental activity can produce unpleasant effects.
  • Affects the length and quality of sleep. Heavy caffeine users suffer from sleep-deprivation because their nervous system is too stimulated to allow them deep, restful or prolonged sleep.
  • The American Medical Journal has reported a correlation between caffeine and decreased bone density or osteoporosis in women.

In addition to the above effects prolonged or very heavy caffeine use can produce the following:

  • `Caffeine nerves’ a jittery feeling with shaking hands, palpitations, and wobbliness in the legs.
  • Caffeine addiction which involves nervousness, irritability, agitation, headaches or ringing in the ears.
  • Causes your adrenal glands to release their hormones into your bloodstream
  • Causes blood sugar, or blood glucose, to be released from storage through the effects of the adrenal hormones. This gives you a temporary lift but requires your pancreas to over-work. This is because your pancreas now has to produce extra insulin to reduce this  extra blood sugar. Once the extra insulin has ‘mopped up’ the extra blood sugar your temporary lift from the caffeine ends. Your vitality level is back to normal. However in heavy caffeine users the pancreas, in time, becomes over-sensitive and over-zealous. Now it begins producing too much insulin – it ‘mops up’ not just the excess blood sugar but the blood sugar you need to feel alert and energetic. The initial effect of this is a let-down effect and a craving for more caffeine to give you a further boost. A later effect can be excessive and chronic tiredness, even on  waking in the morning. Some people find that many of the psychological complaints common to reactive hypoglycaemia (the emotional yo-yo effect, shakiness, palpitations, weakness, tiredness, etc.) disappear within a few days of stopping caffeine.

NOTE: The fact that caffeine can produce these sensations and symptoms does not mean that it is the ‘only’ cause of such symptoms. But if you experience similar symptoms and your medical advisor confirms that they do not have a verifiable organic cause then you may wish to cut out caffeine for a few weeks to see if the symptoms reduce or disappear.

On the other hand…

… some research indicates that the caffeine in coffee (though not in cola) can be beneficial in preventing heart disease (see 1 below) – or, at least, that coffee drinkers have a lowered incidence of heart disease. Nevertheless they were unable to confirm that one caused the other nor why this apparent relationship might be appearing.

Sources of caffeine

  • The richest sources of caffeine are tea, coffee, cola drinks, some over-the-counter medications, chocolate, and cocoa.
  • As little as 20 mgs of caffeine can produce noticeable body and mood changes. As a very rough guide to how much caffeine you may be taking on a daily basis…
  • An average cup of tea contains around 50 mgs of caffeine.
  • An average cup of instant coffee contains around 70-100 mgs. Instant decaffeinated coffee contains about 3 mgs.
  • A 6 oz cup of espresso coffee (much larger than the normal cafe cup, incidentally) contains about 80-90 mgs. A single-hit cappuccino will contain the same amount.
  • Filter coffee (called ‘drip’ in the US) can contain 25-50% more caffeine than instant.
  • A 340 ml or 12 oz can of regular or diet cola contains between 35 and 45 mgs. of caffeine depending on the brand
  • Some so-called ‘energy drinks’ contain very high doses of caffeine – equivalent to to 4 or more cups of strong coffee in one dose! (See 3 below)
  • One ounce or 28 grams of chocolate contains about 10-15 mgs .
  • (An average cup is about 6 UK fluid ounces or 170 ml. Your precise intake of caffeine will, of course, vary with the strength of the drink. One person’s mug of instant coffee might have 75 mgs while another person might prepare a 200 mgs hit! Useful link: CoffeeFAQ)

Caffeine Withdrawal Symptoms

  • Physical and/or psychological addiction to caffeine is common and withdrawal symptoms usually can occur within 6-18 hours after suddenly stopping caffeine intake.
  • Withdrawal effects vary considerably from one person to another and can include headaches, drowsiness, lethargy, irritability, trembling, restlessness, and reduced concentration.
  • As with any addictive drug our sensitivity to caffeine reduces with use – so we need progressively more of it to get the same hit.
  • Avoid ‘cold turkey’ – don’t cut out caffeine straight away!
  • To avoid uncomfortable withdrawal effects it is wise to ease off caffeine over a period of 7-14 days to reduce the discomfort. Reduce and then stop the richest sources (especially coffee) first. It is unwise, particularly if you are a heavy user, to suddenly stop caffeine altogether.
  • Reducing caffeine too quickly can cause a quite dramatic drop in blood pressure, due to the body becoming over-sensitive to adenosine, and this can cause more blood to gather in the head producing a migraine-like headache.
  • Muscle cramps, giddiness, excessive sleepiness, and lack of concentration are other common withdrawal effects from going ‘cold turkey’ on caffeine.

Tiredness and drowsiness

When you stop caffeine you allow your body to catch up on its lost rest. This takes some time.  Using caffeine to force yourself into activity is like flogging an exhausted horse.

For the first few weeks after stopping caffeine you may find that you are sleeping deeper and for longer. For this reason it is a good idea to allow yourself an extra hour per night for a few weeks, increasing this if you continue to experience lethargy in the mornings.

If you feel drowsy during the day use breathing exercises preferably out of doors, to alert yourself.

And remind yourself that the drowsiness is a sign that you are allowing your body to get back into a more normal state and that your natural energy levels will soon return once things have got back to normal after the onslaught of the caffeine regime.


There’s a related article on our blog:

References to check out for yourself:

(1) Article in The Independent (August 2008)

(2) Wikipedia also has an excellent and fully referenced feature on caffeine

(3) Check out the great UK National Health Service website for a balanced view of the health news – search under ‘caffeine’ and you’ll have reading material for a month or two.


There’s a related article on our blog:

References to check out for yourself:

(1) Article in The Independent (August 2008)

(2) Wikipedia also has an excellent and fully referenced feature on caffeine

(3) Check out the great UK National Health Service website for a balanced view of the health news – search under ‘caffeine’ and you’ll have reading material for a month or two.


Important: please read our caution regarding online advice.


Originally published in the Pegasus NLP Newsletter – 7 August 2000 (and later edited).  You can subscribe to our free NLP Newsletter here and receive this newsletter every few weeks.  © Reg Connolly – but you can freely pass this newsletter on to friends as long as you do so in its entirety, include this message and link: Please contact us if you would like to reproduce this article in your own newsletter.

By Reg Connolly

Scroll to Top