Question

The half-life of caffeine in the human body averages 5 hours. How long would it take a person who has had 8 cups of coffee to recover completely from caffeine overdose, and appear to only have had one cup of coffee? Show your work.

Answer 1

Based on the NCBI data we can extract some amount of information regarding caffeine

1 cup of coffee equivalent to 100 mg

8 cups of coffee equivalent to 800 mg

The upper limit to consume the caffeine is 400 mg of caffeine per day.

Overdose amount of caffeine = 800-400 =400 mg

Half life of caffeine in human body = 5 hours

It means that after 5 hours, the amount of caffeine in the human body will remain half of the initial amount.

To recover from the overdose of caffeine i.e. 400 mg from the initial 800 mg, the person will take 5 hours.

In the next 5 hours, the amount of caffeine in the human body will remain 400/2 = 200 mg

In the next 5 hours, the amount of caffeine in the human body will remain 200/2 = 100 mg

After 15 hours, appear to only have had one cup of coffee equivalent to 100 mg.