More Caffeine Vicar? A look at caffeine and its potential effects on sleep and mental well-being.

Caffeine is a nervous system stimulant, the best known source of which is the coffee bean.

Global consumption of caffeine has been estimated at 120,000 tonnes per year, making it the world's most popular psychoactive substance.

Here are some interesting facts about caffeine:

  • Caffeine is present not only in coffee but also in tea and chocolate, and is a common ingredient in soft drinks such as cola and energy drinks.

  • A cup of coffee may contain around 8--175mg of caffeine. Up to 400mg of caffeine per day is considered safe consumption for the average adult.

  • In 2020, almost 10 million tonnes of coffee beans were consumed globally.

  • Decaffeinated coffees do in fact contain caffeine in many cases - some commercially available decaffeinated coffees contain considerable levels.

  • Caffeine is toxic to birds, dogs and cats and has a pronounced adverse effect on various insects and spiders (see picture below).

The drastic effects of caffeine on spiders

Common effects of caffeine ( may vary with individuals):

  • Caffeine can relieve or prevent fatigue and drowsiness and improve cognitive performance.

  • Caffeine stimulates certain parts of the autonomic nervous system, causing increased blood pressure and heart rate, and increased urine output. (Tolerance to these effects often develops with chronic use).

  • Caffeine can prevent the onset of sleep by blocking the uptake of adenosine (a chemical that makes us drowsy and ready for sleep).

  • At normal doses, caffeine has a variable effects on learning and memory, but it generally improves reaction time, wakefulness, concentration and motor coordination.

  • Caffeine improves athletic performance.

  • Caffeine can increase the effectiveness of some medications, such as those for headaches.

  • At high doses, typically greater than 300mg, caffeine can both cause and worsen anxiety.

  • Caffeine affects gastrointestinal motility and gastric acid secretion. More than 4 to 5 cups of coffee or energy drinks per day can cause stomach upset.

  • Mild withdrawal symptoms such as sleepiness, headache and irritability can occur with abstinence but are not thought to last longer than 24 hours.

How much caffeine do you drink on an average day?

If you feel that your caffeine intake may be contributing to your anxiety, you may consider reducing your intake. For some people, discontinuing caffeine use has been shown to significantly reduce anxiety.

If you feel that your caffeine intake is affecting your sleep, you might consider cutting down, or at least regulating the timing of decaffeinated drinks,.

Peak blood concentration of caffeine is reached within 1-2 hours of intake. In healthy adults, caffeine's half-life is around 5 hours. Therefore minimising intake after midday may help if you are struggling with sleep.

Tips for cutting back on caffeine

If you want to cut back on caffeine you could try these suggestions:

  • Track how much caffeine you have each day (see table below for typical values).

  • Work out the times when you ‘need’ it most, for example, while working, studying, relaxing or socialising.

  • Set a goal of how much you want to limit yourself to, and when you want to have it, for example, you might decide to have only one coffee in the morning at breakfast.

  • Substitute the other times you normally have caffeine with non-caffeinated alternatives, such as decaf coffee, herbal tea or sparkling water.

  • Decide how you plan to cut back. Do you want to go cold turkey? Or do you prefer to reduce the amount slowly?

Product Estimated Caffeine Content……….

Typical caffeine tablet 100mg

Cup of instant coffee 60-80mg

Cup of brewed coffee 80-120mg

Cup of black tea 10-50mg

Can of cola 375ml 80mg

Red Bull 250ml 80mg

And do remember, caffeine is no alternative to getting a good night's sleep!