Caffeine makes us feel "high" because it is a stimulant, and stimulants have a large impact on our body. In high doses over a short amount of time, it can cause the heart to beat faster than usual and erratically, which can eventually be fatal.
This was what happened to a healthy teenager from South Carolina in April this year. He collapsed after drinking a latte from McDonald's, a large Mountain Dew soft drink and then an energy drink in a container the size of a large soft drink, in just under two hours. He died from a caffeine-induced cardiac event causing a probable arrhythmia (a condition whereby the heart beat is too fast or irregular)
According to caffeineinformer.com, a McDonald's latte has 142mg of caffeine, a 570ml (20oz) Mountain Dew has 90mg, and a 450ml energy drink can have as much as 240mg. This means that he would have consumed around 470 mg of caffeine within 2 hours.
Mayoclinic states that for most healthy adults, up to 400mg of caffeine a day is a safe amount to consume. Meanwhile, adolescents should limit their caffeine intake to under 100mg. So if you're someone who consumes energy drinks and/or several cups of coffee a day, especially black coffee, be sure to read the labels to make sure you stay within the safe range.
Caffeine overdose may produce the following symptoms, according to Healthline and Inc.com:
- dizziness
- diarrhea
- increased thirst
- diuresis (increased urination)
- difficulty in falling asleep
- headache
- fever
- irritability / jitters / restlessness
- Heartburn / reflux
The above are not so severe and should go away when you limit your caffeine intake and drink more water.
- trouble breathing
- vomiting
- hallucinations
- confusion
- chest pain
- irregular or fast heartbeat
- uncontrollable muscle movements
- convulsions
Babies can suffer from caffeine overdose too if their breast milk contains excessive caffeine. Hence, it is important for pregnant and breast-feeding Mums to limit their caffeine intake.
Ultimately, if you find yourself having to rely on energy drinks or coffee to stay energised, a much healthier and more effective way in the long term is to get sufficient sleep. Check out previous articles here and here on how to fall asleep more easily and getting better-quality sleep. If all else fails, seek professional help as long-term insomnia has very harmful effects on the body.