We all know this person – do not speak to them until they have had a cup of coffee. They will not be nice. They will not be alert. Proceed with caution.
You may even be this person.
Then, 3 or 4 p.m. rolls around and the same thing happens – you may be cranky or tired. Some lose the focus required for work or school.
What is going on here? What does caffeine do to your body? And how long does it last?
Caffeine and its effects are actually fairly complicated and scientists still aren’t sure exactly how it works. We try to break it all down.
Caffeine effects, explained
Caffeine consumption averages around 76 mg per person per day in the United States and Canada, so it’s important to know and understand what it does.
Caffeine is a naturally occurring substance found primarily in coffee, but also in tea leaves and cacao nuts. It can also be created synthetically in a lab.
Caffeine is considered to be a stimulant drug. Some people report feeling alert and energized, while others feel jittery and anxious. Caffeine even has a few medical uses – it can be added to certain pain relievers to help with migraines or decreased respiration (breathing) in infants. Recently, there has also been a pleasant surprise: three cups of black, caffeinated coffee can help your liver function. Dr. Blanca Lizaola-Mayo, MD, a transplant hepatologist (liver doctor) and the Medical Director of the Liver Transplant Center at the Mayo Clinic in Arizona says with a smile, “A least three cups of coffee a day will keep the hepatologist away.”
What does caffeine do to our bodies?
Caffeine works against the effects of the neurotransmitter receptor. How a reduction in the function of neurotransmitter receptors leads to the effects of caffeine (wakefulness, attention) is unclear, however, it is hypothesized that high levels of adenosine promote sleepiness, so if the receptor is not functioning properly, your brain might not be getting the signals that it needs to rest.
How long does caffeine last?
The half-life (the amount of time it takes for the amount of a drug in your body to be cut in half) of caffeine is between 4-6 hours. So even if you feel the effects starting to wane because of the decreased dosage, you still have some caffeine in your system after a few hours. For some, this may be why it’s difficult to sleep after drinking caffeine, even if it was earlier in the day. For others, this amount is not sufficient to have a stimulating effect. It’s dependent on the individual person.
Read more about caffeine, coffee here:
Energy drinks:Do energy drinks do more harm than good?
How much caffeine is dangerous?Here’s what to know before having that next cup.
Study says:Drink 2 or 3 cups of coffee a day? You might live longer – especially if it’s ground.
The tea on tea:Millions of Americans drink tea daily. This is why many choose green tea.
