We’ve all been there: You had a late night, and you’re struggling to keep yourself alert and attentive. You reach for another cup of coffee to try and give yourself that energy boost, but it just doesn’t seem to have the same effect anymore. What went wrong?
We’re all familiar with the effects of caffeine dependency. You don’t feel like yourself unless you’ve had your cup of joe in the morning. Without it, you get headaches and you feel tired, irritable, or even nauseous. But what if you’re not yet dependent? As it turns out, the struggle to feel perky has a lot to do with consistency, and not just quantity. Even if you limit your caffeinated coffee consumption to just one or two cups per day, your body gets used to the consistency.
These effects were recently analyzed in a study published in the Progress in Neuro-Psychopharmacology and Biological Psychiatry journal. For the study, which took place in the Institute of Aerospace Medicine in Cologne, Germany, researchers recruited a small group of 26 participants. Each participant was randomly assigned to a group that drank either caffeinated coffee, at 300 milligrams of caffeine per serving, or decaffeinated coffee. None of the volunteers knew which group they were in. The research took place over five days, and all participants received only five hours of sleep per night.
Each morning, the study volunteers had to rate their subjective sleepiness level, and the researchers used tests to determine their levels of vigilance, alertness, reaction time, accuracy, and memory. Then, each participant in the caffeine group received a cup of caffeinated coffee with breakfast and a half-cup of coffee at lunch. Those in the decaf group received decaffeinated coffee at breakfast and lunch. The participants were then asked three more times throughout the day to rate their sleepiness level. At bedtime, the researchers measured the amount of caffeine still left in the bloodstreams of caffeinated participants.
As expected, the researchers found that all participants reported increased sleepiness as the consecutive days of the study moved along, regardless of the type of coffee they drank. Also as predicted, the volunteers in the caffeinated group reported that the regular coffee helped counteract the effects of sleep deprivation. Those volunteers also performed better on tests for sustained and selective attention.
However, something interesting happened on the fifth day of the experiment: There was no difference between those drinking regular coffee and those drinking decaf. In other words, the caffeinated coffee drinkers found themselves in the same boat as the decaf group, reporting similar levels of sleepiness and performing at similar levels on cognition tests, even after they had consumed their coffee. Why might this be?
The body quickly adapts to caffeine. In fact, a tolerance can form in just three to five days if the drug is consumed on a regular basis. Note that the length of time it takes to become dependent on caffeine will vary from person to person, as certain genetic factors and lifestyle factors are involved that can cause some people to metabolize caffeine more quickly than others. That includes weight, as a higher weight can increase tolerance levels, and smoking, which can dramatically reduce the time it takes to metabolize caffeine.
Why is this research so important? About 69 percent of Americans get less sleep on weekdays than they think they need, according to several sleep studies. This is true even if the optimal amount of sleep per night is actually around 7 hours, and not 8. In cutting sleeping hours short, even just by 20 minutes, a person can impair their performance and memory throughout the next day. As the study’s co-author, Denise Lange, explained, “Our study indicates that moderate coffee intake can mitigate some repercussions of reduced sleep over a few days, however, this is not a substitute for a good night’s sleep in the long term.” Thus, it might be a good idea to not only cut down on your cups of regular coffee per day, but to prioritize sleep to the best of your ability.
Switching to decaf on occasion, or on the regular, has other benefits, too. A 2012 Nutritional Neuroscience study performed at the Mount Sinai School of Medicine suggests that drinking decaffeinated coffee can improve memory function and reduce risk factors for dementia and Alzheimer’s disease and improve symptoms of type 2 diabetes. Over the course of five months, researchers learned that the brain more effectively metabolized glucose and used it for energy in decaf coffee drinkers.
So, how can you prevent yourself from developing a tolerance for caffeine so quickly, to the point that it doesn’t help stimulate you after a bad night’s sleep? The solution is actually quite simple. On the weekends, get plenty of sleep and try to drink only decaf coffee. It’s also a good idea to drink decaf during the week on the days when you don’t need that extra energy boost. With this simple swap, your perkiness should come back when you need it the most.