Sleep Deprivation Makes Caffeine Ineffective 

Coffee, and other highly caffeinated drinks, is a favored and staple beverage that is consumed at all times of the day, in fact many report being unable to start or continue their day without at least one cup of something caffeinated. From coffee and soft drinks to green and black teas, this stimulant is almost a necessity, but when does it stop being effective?

In a study published by the Journal of Experimental Psychology: Learning, Memory, and Cognition, a group of participants were subjected to a night of sleep deprivation and then asked to complete a reaction time test and a “place-keeping” test which was designed to be completed without skipping or repeating steps.

The results of this study showed that sleep deprivation impaired performance on both test types, but that caffeine did help to some degree, specifically with the easier task. The more difficult place-keeping task did not result in improved performance with caffeination. 

“We found that sleep deprivation impaired performance on both types of tasks and that having caffeine helped people successfully achieve the easier task,” said Kimberly Fenn, PhD, an associate professor in the department of psychology at Michigan State University, in a press release. “However, it had little effect on performance on the place-keeping task for most participants.”

Fenn noted that the most important takeaway from the study is that while caffeine may help you stay awake and pay attention to a task, it does not maintain or improve performance or help to prevent errors. “We are interested in procedural errors because they can be quite dangerous. For example, many medical professionals, such as surgeons, need to work long hours throughout the night,” said Finn.

The types of tasks that should be avoided while sleep deprived, according to Finn, are those that could cause serious consequences such as driving, operating heavy machinery, or performing tasks where errors could cause significant negative effect or harm. Alternatively, tasks that you would not perform while intoxicated can fall under the same umbrella. 

So how much caffeine is too much? 

400 milligrams (mg) of caffeine per day appears to be safe for human consumption in healthy adults—about 4 cups of coffee, 10 cans of soda, or two energy shots, but caffeine levels can vary. Powder or liquid caffeine, on the other hand, can cause someone to ingest nearly toxic levels of caffeine. The U.S Food and Drug Administration has stated that one teaspoon of powdered caffeine is equivalent to about 28 cups of coffee. This level can cause serious health problems and even death.

Caffeine can disrupt normal sleep patterns and cause you to lose sleep at night and can cause a cycle of sleep deprivation which is then masked with caffeine. 

Children and adolescents are cautioned to monitor caffeine intake and to be careful of consuming alcohol or other drugs and caffeine at the same time. Women who are pregnant or trying to become pregnant should take care to limit caffeine intake to less than 200 mg per day. Generally, even healthy adults should watch their caffeine intake, especially those who are sensitive to its effects or are taking certain medications.

Signs you may want to cut back on caffeine intake include:

  • Drinking more than 4 cups a day 
  • Headache
  • Insomnia 
  • Nervousness
  • Irritability
  • Frequent or inability to control urination 
  • Fast heartbeat
  • Muscle tremors

To curb the habit, keep tabs on your caffeine intake during your daily consumption, cut back slowly by drinking one less caffeinated beverage or avoiding late day consumption, switch to decaf, shorten your brew time to decrease the amount of caffeine, and pay attention to ingredients of supplements and medication and opt for caffeine-free options.