If you remember the first time you tried pre-workout, it might have been something like this...
Tons of people love using pre-workout. They like the way it makes them feel - usually super hyped up, high energy, and excited to go do literally anything physical - and they believe it makes them perform better in the gym or in sport.
Before I get into the title of this post, let me be clear that pre-workout can be a useful tool to help you get the most out of yourself in the gym. I use pre-workout myself, though it's probably not one you're familiar with. I'll share what I use in just a few minutes if you're curious.
Even if not physical, the mental benefits of taking pre-workout can be substantial: increased motivation to train, increased perceived potential, desirable physical sensations of power (i.e. tingling from beta alanine), increased focus, and using pre-workout as a cue or part of your routine to put your body and mind into a favorable state to train.
Physically, common ingredients in pre-workout supplements claim to produce a variety of temporary physical benefits including increased endurance capacity, increased mental focus, and increased maximum force production. Some of these ingredients and effects even have legitimate scientific data to back them up.
Regardless of the data, I personally believe it can be argued that even if benefits are due to the placebo effect, who cares? It still helps. Benefits are great regardless of if they are placebo or not as long as they don't also harm you or others.
But that's the thing - your pre-workout could be causing you more harm than good if you're not careful.
From my own experience and in talking to others, the two feelings people expect most from pre-workout are extremely high energy and motivation and the tingling or pins-and-needles feeling that many pre-workout supplements provide. Those sensations come primarily from two ingredients: caffeine and beta alanine.
In appropriate doses, those ingredients and their effects are generally just fine for most people. What I want to discuss in this post is workout timing, the importance of sleep, and the half-life of caffeine.
Let's take a step back and look at the major training factors from a high level. What leads to progress? In simplest terms, one way training can be broken down is into these three important categories:
1) Stimulus/progressive overload
If you don't give your body a reason (stimulus) to get stronger, it won't get stronger. People who work a sedentary job and spend the rest of their time doing sedentary activities will develop a body well suited to that lifestyle. People who live active lives and push their bodies intelligently to their limits will develop bodies well-suited to that lifestyle. As with anything whether it is physical or not, without stimulus there will not be progress.
The second part of training as we are looking at it here is nutrition. Without the resources to repair and build your body up from a stimulus, your progress will be hampered. You may still experience favorable internal adaptations even with poor nutrition (i.e. increased aerobic capacity), but the physical improvements (i.e. increased muscle size, more favorable body composition, etc) may be limited without proper nutrition. You can't build a Ferrari out of Prius parts, and you can't build a physically powerful body without proper nutrition.
The third component is sleep. I believe sleep is the most underrated and the most difficult component of training to get right. I know it is the component I personally struggle with the most. The actual physical improvements that your body experiences from stimulus and appropriate nutrition don't occur while you are training or even in the hours after training while you're awake - they occur when you sleep.
Your body literally produces human growth hormone (HGH) during deep sleep cycles (sleephelp.org), but deep sleep cycles only occur after you've been asleep for hours and increase in duration the longer you've been asleep. That means that the most beneficial sleep cycles from a training perspective occur in hours 7-9+ of you being asleep - the hours most of us don't get.
How does this relate to pre-workout? Well, as we discussed earlier, most pre-workouts contain high amounts of caffeine. Caffeine is eliminated from the human body at a half-life rate. This means it takes a certain amount of time for half of the caffeine in your system to be removed. Then it takes that same amount of time for another half of the remaining caffeine to be removed, and so on. The half-life for caffeine in humans is 3 to 5 hours (sleepeducation.org).
For example, if you take pre-workout after work at 5:00 pm that has 200mg of caffeine in it, which is pretty typical, it could be 10:00 pm before your body eliminates just half of that caffeine. That means that at 10:00 pm you could still have 100mg of caffeine in your system - about the same amount that a full cup of coffee has. In other words, by taking pre-workout at 5:00 pm you will have the same amount of caffeine in your system as drinking a caffeinated cup of coffee at 10:00 pm.
How do you think you'll sleep with that much caffeine at bed time? Sure, you might have a tolerance for caffeine. However, caffeine can still block essential sleep-conducive physiological processes and increase adrenaline production even if you don't feel it's effects, which makes achieving true deep sleep states more difficult and less likely. That means you will probably not make it to the most beneficial sleep stages where the most potent growth hormone release occurs.
Another factor to consider is that most adults have a limited sleep window to begin with. Assuming you go to sleep earlier than most at 10:00 pm and you wake up at 6:00 am, your maximum potential sleep time is 8 hours assuming you fall asleep immediately (not likely) and stay asleep the entire night (is that even a thing?). Now if you still have the equivalent of a caffeinated cup of coffee in your system, how do you think your first few hours of sleep are going to go?
Let's say you go to bed before most people at 10:00 pm, took 30 minutes to actually fall asleep, woke up once or twice during the night, and woke up at 6:00 am. You might have gotten 7 hours of sleep and the quality was questionable. You wake up tired, drink some more caffeine throughout the day, and take 200mg more caffeine in your pre-workout at 5:00 pm. Essentially, you didn't get enough sleep the night before, loaded up on more caffeine, and won't get enough sleep again tonight because of it. If you are training, you already require more sleep than normal just to recover, far-less progress. Do you see a nasty snowball forming here?
If we take 9 hours as a somewhat realistic maximum sleep duration to promote recovery and physical adaptation (meaning you need to fall asleep at 9:00 pm to wake up at 6:00 am), you would be missing out on at least 730 hours of the most potent growth hormone-releasing sleep stages available to you per year. How much better do you think your progress could be with that valuable sleep than without?
With all of that said, here's my suggestion: if you work out at night, look for a pre-workout WITHOUT caffeine in order to maximize the sleep you can get based on the rest of your life (work, etc). Even better would be to train in the morning if you have that option assuming you go to bed early enough to still get enough sleep.
You might have to look around a bit, but there are pre-workouts out there without caffeine. I myself use a non-caffeinated pre-workout from Barbell Medicine. No, I am not getting paid to recommend or promote their product (hence, no link). It's just what I choose to use. It still has creatine and beta alanine, so you'll still get that tingly feeling and all the proven benefits of creatine - just without the caffeine.
Since I stopped having caffeine before I train at night, I can go to bed earlier and I sleep better. My training results have improved significantly, I feel better during the day, and I only have about 80mg of caffeine in the morning as part of my routine. That leaves about 13 hours to get most of a measly 80mg of caffeine out of my system before bed. I get more and better sleep again, wake up rested, and have only a small amount of caffeine the next day again.
That's a snowball effect I'll take.
Everyone is different. I'm not here to tell you how to live your life. I just want to give you something to think about. With how important sleep is to your overall long-term health, it may be worth weighing (or even better, testing!) the benefits of training with caffeine versus training without.
Chronic sleep loss has been linked to increased risk of hypertension, diabetes, obesity, depression, heart attack, and stroke (Sleep Disorders and Sleep Deprivation: An Uhmet public Health Problem). In today's 24/7 fast-paced more-is-better work environment, make sure to take care of yourself and get some sleep so you can get the most out of every area of your life!