Runners are no stranger to the feeling of fatigue. But different kinds of fatigue require different solutions. Learning what kind of fatigue you are having (and how to get out of it) can make the difference between training consistently and training not at all. Between your body gaining fitness and your body breaking down.
WHY ARE YOU FATIGUED?
This sounds like a dumb question. “Did you see how many miles I ran this week?” But this is an important question we should explore. I’m going to address four different types of fatigue and the stressors that cause them. These four types are based on a fantastic podcast by former USA marathoner Ryan Hall. Pay attention to what causes each one, what it feels like, and what you should do about it.
MUSCULAR FATIGUE
Muscular fatigue is a drop in the ability of the muscles to generate force.
What causes it? The most common reason for runners to have muscular fatigue is due to strength training. The more you push your body in this area beyond its normal limits, the more fatigue you’ll incur. I always dread the first time I lift weights after a period of inactivity. No matter how slow I go, I’m always ridiculously sore for the next two days.
Rest assured though, even on days when you’re not sore, the muscles are still incurring fatigue at some level.
What it feels like? Thankfully, this is an easy one to spot. The most obvious example is like I already mentioned – extreme soreness the day or two after strength training. Aside from this though, your legs just may feel flat or unresponsive on a workout.
What to do about it? Muscular fatigue usually subsides within a day or two. It’s just a matter of the physical muscles being replenished. Taking some extra protein either after you lift weights or before bed will help with muscle recovery. If you have a big workout on tap and you feel muscular fatigued, I recommend pushing the workout back a day. It’s better to perform the workout with some quality than force it and be sloppy.
SLEEP FATIGUE
Sleep fatigue is a general drowsiness and lack of energy that can’t be overcome.
What causes it? Obviously, a lack of sleep is the culprit here. Any new parent or procrastinating college student knows what this feels like. Not sleeping enough puts extra stress on the body – as if your body is going through a second workout every day when you don’t get enough sleep.
A few nights of severely missed sleep makes the cortisol levels shoot up in your body. High cortisol = high stress for the body. Poor sleep habits may be to blame, like heavy screen time or high stimulation before bed.
What it feels like? It feels like an inability for the body to wake up throughout the day regardless of the any stimulation (ie: coffee, exercise). You may wake up several times in the middle of the night and not be able to fall back asleep.
What to do about it? Sleep. More. I’ve heard recommendations saying we should sleep enough so that our body wakes itself up naturally in the morning. If you have bad sleep habits, fix them. Improve your sleep habits (less screens, better environment, low stress). Sleep fatigue can be overcome rather quickly with a few good nights’ sleep and training should largely be uninterrupted.
If you improve your sleep habits but are still having trouble falling or staying asleep, you may have whole body fatigue, which is next on our list!
WHOLE BODY FATIGUE
This fatigue is also known as overtraining and is the most difficult to overcome.
What causes it? The process of training every day consists of causing stress to the body (a stimulus) and then the body repairing itself. If I’m in a cycle of not letting my body fully repair itself, I’m eventually going to be unable to do much.
Imagine productive training as digging a hole. At the end of each day, the hole gets filled in again (recovery) and ready for the next day. What happens if I only am able to fill up the hole 75% of the way? I still come back the next day and dig just as far down so that I’m deeper than I ever was. I then fill the hole back in only a little again and the process repeats itself.
This is overtraining. Eventually I’m in too deep and unable to recover at all.
What it feels like? This is a popular question because overtraining is a big deal. It feels like prolonged weakness in everything. You’re generally just fried even at the start of a run, and it lasts for days, or even weeks. The tell-tale sign for me is that the training itself is suffering when it shouldn’t – not hitting workouts, worse times, etc.
If you’re largely hitting paces still in workouts, it’s likely that you are NOT overtrained and should look at the other types of fatigue.
What to do about it? This type of fatigue requires the most drastic change. Taking 2-3 days off of training at a minimum, maybe several more. The longer you’ve been in a bout of overtraining, the longer it will take to get out of it. Fuel the body well during those days. And when you return, use just easy miles for at least a week or two until you can sense that your energy has returned.
ENERGY FATIGUE
Energy fatigue is the body’s way of saying “I’ve run out of fuel. Feed me!”
What causes it? Lack of nutrients to fuel your training causes this type of fatigue. Often it happens if a runner is trying to lose weight or body fat for a period of time. Usually they are already running in a depleted state.
What it feels like? Like there’s nothing in the tank. Your legs feel strong, you’re well-rested, but there’s just no energy level there. If you’ve had to run after a long period of not eating, you may have felt this. It’s not fun! Energy fatigue can cause a lack of motivation as well since our brain is fueled by glycogen (carbohydrates).
What to do about it? This may be the quickest one to resolve. If this is your fatigue, you may be just one meal away from getting your legs back under you again. Instead of taking the extra rest day (as with muscular fatigue or whole body fatigue), you may be just fine if you get a high carbohydrate meal in you.
LISTEN TO THE BODY
The next time you feel fatigued, explore it! What is your body telling you through it? The balance of training and recovery is one of the most difficult balances to strike. It is an ever-evolving target during different phases of your training and is crucial to reaching your potential as a runner. To borrow Steve Magness’s maxim, “stress + rest = growth”. The quicker you can identify the signs of stress (aka: “fatigue”) in the body, the quicker you’ll be able to address it and grow!
If you’ve enjoyed this article and want to see more content like this, consider subscribing to my weekly email list to get articles sent directly to your inbox as well as other valuable content not seen on the website.
