Sometimes a friend of mine will ask me, “Why doesn’t coffee wake me up?”
I consulted with a doctor friend of mine, who wrote me a detailed reply, which I used to create this post. If you’re asking yourself, why doesn’t coffee wake me up, you’ll find the answer here.
Some people seem to be able to drink coffee throughout the day without getting jittery while others can get anxious palpitations after just one cup.
What’s the difference between these people?
Is our response to caffeine changeable?
The aroma of coffee can be a signal to wake up and start the day all on its own, but the real kick-start comes from caffeine.
The reason coffee isn’t waking you up anymore is probably as simple as this: you’ve developed a tolerance for the caffeine. The best way to overcome that tolerance is to cycle your caffeine intake, saving the big caffeine days for the days when you need the biggest boost.
How Does Coffee Wake You Up to Begin With?
The caffeine in coffee is responsible for increased alertness, boost in energy, motivational kick-start, and positive feelings.
Caffeine excites neurons by affecting the function of the neurotransmitter adenosine.
- Adenosine is an inhibitory transmitter that blocks the release of the excitatory signal molecule cyclic adenosine monophosphate (cAMP).
- In other words, adenosine slows down the firing of neurons when it blocks receptors.
- Caffeine competitively binds to the same receptor as adenosine, but it does not have the same inhibitory action.
- By reducing the amount of receptors available to adenosine, caffeine allows more cAMP to accumulate.
- More cAMP means more activation and increased neuronal firing.
It takes about 15 minutes for caffeine to take effect and then around 30-45 minutes to be completely absorbed and reach peak effect.
- This peak lasts for several hours because of its 5-hour half-life.
- Translation: at about 5 hours, about half of the caffeine you consumed will still be present.
- It is eliminated at a constant rate and may take up to 10 hours on average to clear from the bloodstream.
The recommended daily caffeine intake is around 400 mg. Above this amount, negative side effects become more common.
Caffeine comes from both natural and synthetic sources.
The amount of caffeine varies between sources. Here are a few common examples:
- Coffee – 96 mg per cup (8 oz) (Cowboy coffee, though, has slightly more. Which grind you use can also change this. Brands can also matter, like whether you drink Starbucks or Dunkin.)
- Energy drink – 72 mg per cup
- Green tea – 29 mg per cup
- Soft drinks – 34 mg per can (12 oz)
- Dark chocolate – 16 mg per ounce (288 g)
- Some dietary supplements and over-the-counter pain relievers also contain caffeine. The amounts will be listed on the bottle.
What Is Caffeine Tolerance? Is Tolerance the Same as Sensitivity?
Tolerance occurs when the effects of something decrease over time with regular consumption. In the case of caffeine tolerance, you need more caffeine to achieve the same effect over time.
Regular caffeine consumption has been show to cause tolerance after as little as 1 to 4 days.
Tolerance has been studied by looking at its effects on blood pressure, heart rate, exercise performance, and mental performance. One study looking at the effect of caffeine on blood pressure showed that the initial increase in blood pressure disappeared after 8 days.
Caffeine sensitivity results from genetic and lifestyle factors that predispose a person to either faster or slower caffeine metabolism.
The type of symptoms that sensitivity can cause may vary from person to person. For example, some can be sensitive to anxiety and other to insomnia and sleep disturbances.
Some factors that affect caffeine sensitivity include:
- Genetic factors can affect the rate of metabolism.
- Increases in weight can reduce sensitivity.
- Smoking can cause caffeine to be metabolized more quickly, reducing sensitivity.
- Older adults tend to be more sensitive.
- Particularly to effects on sleep disturbance and insomnia.
- Pregnancy increases sensitivity because of fetal absorption and slowed renal clearance.
- People who are prone to anxiety or have an anxiety disorder may be more sensitive.
When considered together, sensitivity forms our baseline response to caffeine and is determined by biological factors that are relatively constant over time. Tolerance changes our response on top of this baseline and is easily modified by our pattern of usage over time.
Caffeine or Lack of Caffeine?
When caffeine is consumed regularly, the positive effects of caffeine can often be more related to the reversal of withdrawal symptoms than boosts above normal.
Yes, this means that extra satisfying cup of coffee you need in the morning to get going can be a sign of caffeine dependence.
Dependence occurs when tolerance develops and withdrawal symptoms occur when use is abruptly stopped.
Withdrawal symptoms can appear 12 to 16 hours after the last use of caffeine. Symptoms peak around 24-48 hours and can include:
- Sleepiness
- Lack of concentration
- Anxiety
- Irritability
- Headache
In other words, people who have caffeine regularly may not feel like it affects them because they are using it to avoid or reduce withdrawal symptoms and return to feeling normal rather than getting an effect above baseline.
How Can You Get the Most from Your Cup of Coffee?
Tolerance can be overcome by consuming more than you normally do, but that strategy only gets you so far before you suffer the negative side effects.
Unfortunately, that means the best way to manage tolerance in order to get the most benefit from caffeine consumption is to give yourself a break by decreasing intake and/or consuming caffeine less often.
- In order to avoid withdrawal symptoms, a slow reduction in caffeine is preferred over an abrupt stop or drastic change.
- Depending on how much you regularly consume, complete return to a baseline sensitivity can take 2 weeks to 2 months.
What is the ideal pattern of caffeine consumption if you want to maximize the benefits, limit tolerance, and avoid withdrawal symptoms?
- Cycle your intake.
- Drink a high amount one day, ideally saving it for a time when you need a boost the most.
- Then reduce your intake on the other days.
- For example, if you have 4 servings on day one, have 2 the following day, then one, and then abstain for a few days or until you need it.
- Drink coffee with a meal rather than an empty stomach.
- This can slow absorption and give you an extra boost from the food along with the caffeine.
Conclusion
Why doesn’t coffee wake me up?
You’ve just developed a tolerance for the caffeine in your coffee. The solution is to cycle your caffeine intake so as to minimize the effects of tolerance.
Increasing your consumption can turn into a never-ending treadmill, so that’s not the solution. The real solution is to have high-caffeine days and lower-caffeine days.
One of the sources used to research this post: https://pubmed.ncbi.nlm.nih.gov/1888264/