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To become a better runner, you need to strategically push yourself out of your comfort zone. That’s why runners do speed workouts and long runs; they stress the body beyond what it’s used to, which forces it to adapt (read: get stronger). “This process involves breaking down muscle tissue and damaging cells,” explains Todd Buckingham, an exercise physiologist at the Mary Free Bed Sports Rehabilitation Performance Lab. “You train and break the body down so it must rebuild itself stronger than before.”
That rebuilding isn’t happening during your workout, though: It happens during recovery. When you don’t prioritize rest and recovery and you continue to put more and more stress on your body, it will eventually break down and your performance will suffer—that’s called overtraining.
True overtraining occurs over months; in the shorter term (read: days and weeks) you might be dealing with nonfunctional overreaching, according to research published in the journal Sports Health. While true overtraining may not be as common as nonfunctional overreaching, one older study published in the International Journal of Sports Medicine found that around 60 percent of elite female runners and 33 percent of nonelite female runners will deal with overtraining at least once in their lives.
Many athletes use the terms nonfunctional overreaching and overtraining interchangeably, says Heather Hart, an ACSM-certified exercise physiologist and running coach. They do share similar symptoms, and nonfunctional overreaching can lead overtraining—“but nonfunctional overreaching can typically be relieved by days or weeks of reduced training, rest, and adequate caloric intake,” she explains, while “true overtraining syndrome can’t, and, in many cases, can last months or even years.”
Either way, constant cumulative stress without adequate recovery is a slippery downward slope—and your body will give you plenty of signs that you’re in need of some R&R.
Signs and Symptoms of Overtraining
First, you’ll likely experience training-related symptoms:
- a plateau or decline in performance
- depleted energy stores
- an increased perception of effort in training
- unusual feelings of heaviness, stiffness, or soreness in muscle
- recurrent injuries.
What’s happening here is that your body is never fully recovering from a single workout, and because it can’t ever get back to homeostasis—aka a relatively stable equilibrium—you’re starting each subsequent workout at a deficit.
“A decrease in performance is a result of poor to no recovery in the body, heaviness is a result of the damage to the soft tissue that still needs repairing, and all of that typically results in injury,” explains Pablo Estrada, a doctor of physical therapy and sports medicine specialist in El Paso, Texas.
There are other more general physical side effects as well. You might notice your resting heart rate or blood pressure is higher than normal, hormonal changes and disruptions, sleep issues, like insomnia or waking up feeling unrested, digestion issues, a lack of appetite and/or weight loss, reproductive issues, and repeated colds.
“When you don’t allow the body to recover, your muscles and cells could be in a state of chronic inflammation,” says Buckingham. “This can reduce ATP production (ATP is where the cells of the body get their energy from), and not having enough energy can have serious consequences on the body and its physiological processes that may manifest in a variety of ways.” Translation: Your body has to work a lot harder just to function at the most basic level.
Plus, when your body is constantly burning energy (because it can’t recover and return to homeostasis), you’re likely not giving it enough calories. And if you’re not giving your body enough fuel for basic functions, “the body will pull those resources from other parts of the body,” says Estrada. For example, if you’re burning more calories than you consume, your body will drop its estrogen levels, which can cause you to lose your period; that dip in estrogen will also affect your bone density, which can lead to stress fractures and broken bones.
“If there isn’t a balance between training and recovery/rest/nutritional intake, the recovery process begins to fail,” says Hart. “The accumulation of excessive stress leads to the production of proinflammatory proteins (aka cytokines) that can alter the function of your central nervous system, which can affect sleep and appetite, and endocrine systems, which can affect tissue rebuilding and recovery as well as your immune and reproductive systems.”
Then, of course, there are the mental or emotional issues you might experience:
- persistent feelings of fatigue, exhaustion, or low energy throughout the day
- a decline in motivation and/or self-confidence
- a lack of enjoyment in favorite hobbies and interests or other signs of depression
- unusual moods or emotions, such as agitation, anger, confusion, irritability, and restlessness
When cytokines mess with your central nervous system, it can also lead to mood issues (elevated levels of cytokines have long been directly linked to depression). And, of course, it’s kind of a no-brainer that if you’re constantly tired or if easy workouts feel hard that you’re not going to be super motivated to get out and run, right?
What to Do If You’re Overtraining
Once you’ve figured out you’re overreaching, the best thing you can do is give yourself a break. “Focus on reducing your volume and intensity, reducing stress outside of running/training, and prioritizing adequate nutritional intake,” says Hart. (If you’re suffering from true overtraining syndrome, you need to consult with a medical professional, she adds.) That may mean stopping running entirely, but that will depend on how much your performance has deteriorated.
With proper recovery (which includes proper nutrition and sleep, which a 2019 study from the International Journal of Sports Medicine determined to be the single most important factor in exercise recovery), symptoms of overtraining normally resolve in 6 to 12 weeks, research in the British Journal of Sports Medicine found. When you do get back to running, you should build your volume—from 5 to 10 minutes a day until you can handle an hour—before increasing intensity, the researchers recommended.
Gradual progression is also the best way to avoid overtraining altogether. There’s a lot made of the 10 percent rule, that says you shouldn’t up your distance (or pace) by more than 10 percent each week. But runners who averaged 20 to 25 percent weekly increases avoided injuries, per a study at Aarhus University in Denmark, and runners who increased their training load by up to 50 percent per week experienced almost the exact same injury rates as runners who followed the 10-percent rule, according to one study from the University of Groningen in the Netherlands.
Instead, consider your acute-to-chronic workload ratio, or how much you ran this week (your acute workload) versus how much you ran of the past four weeks (your chronic workload). Keeping that acute-to-chronic workload ratio within 0.8 to 1.3 was associated with a low injury risk, research published in 2016 in the British Journal of Sports Medicine determined.
Math not your thing? That’s OK. If you’re questioning whether a workout is the right move or not because you’re experiencing any of the symptoms above, Hart suggests asking yourself: How am I feeling? If my running is getting difficult, is this expected? How am I sleeping? How is my appetite? How is my mood? These can all be symptoms of disruptions in both the central nervous and endocrine systems from too much stress, she says.
A little fatigue is part of the training process, but listening to your body and learning what’s normal and what’s not (a training log can help with that) can help you avoid overdoing things.