The answer is a somewhat complicated: probably. And the reason why took me down a rabbit hole I did not expect to get into- but totally enjoyed.  Before I get into this, let me just put out a disclaimer that coffee is not always right for everyone, however, I thoroughly enjoy it. Some are more caffeine sensitive and there are big differences in the range of time people metabolize it. For others, it may aggravate conditions such as IBS, overactive bladder, or anxiety disorders. It also shouldn’t be consumed in excess (over 400 mg/d, about 4 cups/ day, or less depending on weight) and should be limited in both pregnancy and breastfeeding. That being said, coffee has been associated with health benefits such a decreased risk for diabetes, heart disease, certain cancers, depression, and even neurodegenerative diseases such as Parkinson’s and Alzheimer’s. It can increase alertness and even improve mental and physical performance- all huge positives that are nothing to sneeze at. 

But what about the downside of coffee- the jitters, the mid afternoon crash, interruption to your sleep cycle? Some of these effects can be controlled by two factors- dose and timing. I admittedly was the person that was motivated to get out of bed with coffee- the smell, the taste, the pick-me-up to break through the morning fog- but recently, I’ve changed my habits and have noticed an increase in energy and a decrease in the negative effects. 

So grab a cup of coffee (or not- depending on when you're reading this) and let’s dive into why timing may be key with coffee (or caffeine for the matter). We all produce cortisol (the so-called stress hormone)- it’s often thrown around as a scary negative thing- and in excess, it can be. However, it’s necessary for regulating blood pressure, decreasing inflammation, increasing glucose metabolism, and also plays an important role in sleep/wake cycles among other things. Cortisol should peak in the morning around 7 or 8 am. It’s a big part of what gets us up and going. Coffee slightly increases cortisol production. If we drink coffee first thing out of bed, it is likely to create an excess of cortisol and you may not get the full benefit of your coffee boosting alertness because cortisol is already trying to do its job. Cortisol levels naturally start to dip a couple hours after waking so you may get more bang for your buck out of drinking coffee at that point. 

Cortisol isn’t the only thing being impacted by coffee. When we’re sleepy, it can be partially attributed to a neurotransmitter called adenosine. Adenosine is lowest after a restful night of sleep, but there is still some in our system when we wake up. Caffeine is an antagonist to adenosine- meaning that it binds to adenosine receptors and prevents us from feeling tired. Caffeine doesn't get rid of adenosine- it just delays its effect. Therefore, if you have a build up of adenosine then drink coffee, it can be a recipe for a crash when the caffeine wears off and the adenosine floods the receptors. This being said, cortisol helps to clear residual adenosine from our system. If we allow the cortisol which is naturally elevated in the morning to clear most of the residual adenosine after sleeping then drink our coffee (usually an hour and a half or two after waking) we can avoid that afternoon crash which tends to lead to a cycle of reaching for another cup of coffee. 

Drinking caffeine too much later than the two hours after waking can disrupt both the quality of sleep and the ability to fall asleep. For this reason, it’s recommended to avoid caffeine consumption in the afternoon- about 10-12 hours before sleeping. That sounds crazy right? 10-12 hours?! I thought the same thing, but caffeine has a half life of about 5 hours and a quarter life of 10-12 hours. This means if you typically go to bed at 10pm, it’s best to avoid coffee past 10am or 12pm at the latest. As with most things, individual results may vary. Like I mentioned earlier, there is a big range in the time you may metabolize caffeine and how sensitive you are to it. It’s best to be mindful of just how much caffeine is in foods and drinks you typically have and pay attention to how your body reacts to caffeine and adjust accordingly. 

Ok so just a quick recap on the timing of caffeine… 

To get the most bang for your buck with coffee, it may be best to time your morning brew 90-120 minutes after waking so that you get a boost of continued alertness after cortisol starts to dip naturally with a minimal post caffeine slump because you won’t have as much built up adenosine to create the crash. Also, avoid caffeine at least 10 hours before bed to prevent it interrupting your depth and quality of sleep.

This was a game changer for me and I hope you find it useful too! Just remember to always listen to your body’s cues above all else to see what works best for you.

In good health, 

Victoria Chouklina, RDN

To deep dive even more into this topic, here’s some resources: 

https://www.hubermanlab.com/episode/using-caffeine-to-optimize-mental-and-physical-performance

https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2686145

https://my.clevelandclinic.org/health/articles/22187-cortisol

https://www.science.org/doi/10.1126/science.1228806