Caffeine can add a burst of energy to your morning, however this may not be so useful when you're trying to go to sleep.
Key facts
- Caffeine takes many hours to be metabolized (broken down by the body) so is still in your system more than 6 hours later.
- Too much caffeine can cause headaches, trouble sleeping, abnormal heart rhythms, anxiety, irritability and restlessness.
- Caffeine is found in many drinks, foods and over the counter medications such as some headache or cold/flu medicines.
- If you are pregnant or breastfeeding, reduce your use of caffeine.
- Most people experience withdrawal symptoms if they stop drinking coffee or other types of caffeine too quickly.
Does caffeine really affect our sleep?
Caffeine is a stimulant and has many effects on the body's metabolism, including stimulating the central nervous system. This can make you more alert and give you a boost of energy which is useful in the morning but not helpful if you are trying to go to sleep.
Side effects of caffeine
- It can make you jittery and shaky.
- You may find it hard to fall asleep, stay asleep, or get a good night’s sleep.
- It can make your heart beat faster.
- It can cause an uneven heart rhythm.
- You might experience raised blood pressure.
- Headaches, nervousness, and/or dizziness.
- Dehydration (dried out); especially after a workout
- People can become dependent on caffeine so they need to have more of it.
How much caffeine is safe?
There are no firm recommendations on the amount of caffeine we should consume, so we should be aiming for moderation, say 300-400mg or 3 cups of coffee each day.
- Pregnant women are advised to limit the amount of caffeine they consume each day to around 2 cups of coffee (<200mg caffeine), as pregnancy slows the rate at which caffeine is broken down in the body. High caffeine levels have been linked to low birth weight and reduced fertility in women trying to conceive,
- Children do not need to include caffeine in their diet. Caffeine in children has been linked to irritability, sleep problems, aggressive behaviour and attention and conduct problems.
- Breastfeeding women should be aware that caffeine may have a stimulating affect on their baby.
- Caffeine is present in many more products these days, particularly energy drinks. These drinks contain more added sugar than is recommended and so it is best if these drinks are avoided, particularly for children and pregnant women as we don’t know the effects of early exposure to caffeine.
Learn more
Caffeine New Zealand Nutrition Foundation