Written by
Casey Green
Written by
November 23, 2021

Mile after mile, day after day, runners are constantly dealing with some level of physical and mental fatigue. However, there’s a fine line between expected training fatigue that can be pushed through, and the type of running fatigue that needs to be remedied quickly and purposefully. Running fatigue and all the negative symptoms can ultimately be caused by a variety of factors. Some of these have to do with a runner’s training approach itself. Others are associated with post-run recovery and other factors outside of the physical run.

Our goal at Charge is to keep every runner training in a healthy and happy manner for life! With that goal it’s important to be able to identify and mitigate common causes of running fatigue and its symptoms.

Running fatigue can be easily and effectively avoided!

5 Causes of Running Fatigue and How to Avoid Them 

1. Poor Sleep Habits

We’re not blowing anyone’s mind here. Good, consistent sleep habits are key to keeping your body feeling fresh and rested. This also mitigates the build up of training or running fatigue. Allowing your body to fully recover over an 8+ hour span is an essential element of any runner’s training. As soon as your body becomes sleep deprived your training will require more energy. More energy requirement leads to more fatigue, and so begins a dangerous cycle. 

Improving your sleep habits requires more than just “catching up” on the weekends. Set a consistent relaxation and sleep routine. Get into bed, go to sleep, and wake up at the same/similar times every day. That includes the weekends! Implement proper pre-sleep habits that will help you fall asleep. These habits will also aid you in achieving a deep, restful night of sleep.       

2. Unbalanced Diet

Not maintaining a healthy, balanced, and hearty diet during training can immediately lead to the onset of running fatigue and associated symptoms. Beyond rest and recovery, your body needs fuel! You may feel initially fleet of foot when training on an empty stomach. However, your energy tank is going to empty quickly and those final few miles or repeats are going to be a struggle. Overtime an unbalanced diet will decrease the efficacy of your running development and could very well lead to injury.

To mitigate this, start by stocking your fridge and pantry with the right, balanced fuel sources. Next, be sure to be consistently consuming the proper caloric intake for your daily training regimen. Runners have to eat and in high-training times they MUST eat more. As long as you’re consuming the right things, don’t shy away from a second (or third) portion. 

Proper diet and nutrition is key to avoiding running fatigue.

3. Improper Training Intensities 

All runners can get ahead of themselves a bit when it comes to training intensity. This is especially true without a coach guiding you through your training. It’s hard to not get caught up believing that harder training for longer leads to better performances. It turns out though that science, and much smarter people than myself, have proven that to NOT be true. So let’s take their word for it. 

The first, and most effective, way to avoid this cause of running fatigue is to find a good coach. Leave the pace goals, volume assignments, and workout decisions to an expert. If you don’t have access to a coach, you can follow a simple effort breakdown for each week of your training:

50% of your weekly miles = Efforts/paces at no more than 55% of your max effort    

25% of your weekly miles = Efforts/paces at 40% of your max effort (normally your Long Run)     

25% of your weekly miles = Efforts/paces at greater than 65% of your max effort (workouts)      

4. Vitamin/Mineral Deficiencies

When runners experience unexplained running fatigue symptoms, and eliminate the above sources, a common cause can be a vitamin or mineral deficiency. Notably iron, an essential mineral found in red blood cells that is key to the transport of oxygen through blood. Particularly in female endurance athletes, low iron levels can be particularly prevalent. For runners symptoms of low iron can present as those of overtraining. The reduced capacity to work, poor response to training loads, and eventually poor performances across the board.

Coordinating with your physician, especially if you are at higher risk for low iron or ferritin (iron stores) levels, is the first and primary step to avoiding this cause of running fatigue. Having your doctor check your iron levels will give you all the information you need to make an informed decision about the need for iron supplements, liquid iron, etc. Maintaining that healthy, balanced diet that includes iron-rich foods will also help avoid any long-term negative effects for most runners.  

Beyond iron, it’s important that runners keep track of the proper balance of a variety of vitamins and minerals. Specific supplements used properly can be a helpful aid to avoiding some of these deficiencies that can lead to an onset of running fatigue.


Running fatigue can occur across all types of activities.

5. Mental/Emotional Stress

The effect of mental and emotional stress can not be discounted as it relates to running fatigue and general training exhaustion. A particularly stressful week from any source can have effects on your sleep and diet, but also can directly contribute to poor run training decisions. When mentally and emotionally fatigued, training becomes unengaged and oftentimes turns into simply going through the motions of running with no real purpose or benefit. 

If this occurs, it’s always best to prioritize mental and emotional health over specific training goals. Practicing self-care, even if that means shortening or all-together skipping a run, will over time be far more beneficial than any track workout or tempo run. If running is part of that self-care, great! In this case, focus on the love of the activity. Don’t obsess on paces of mileage, just get out there and have fun! Running is ultimately no fun day after day if there’s not a high level of love involved.