Regardless of whether you’re working with an endurance athlete or a recreational exerciser trying to hit fitness goals, you must know what is overtraining. When you understand what overtraining syndrome is, you’re able to help others avoid this conditioning and help them with recovery, should they experience an overtraining symptom. It’s all part of your job as a fitness professional to prevent injury and decreaed performance.

While it can seem counterproductive to tell your client to slow down, in many cases it’s needed and will ultimately support their training in the long term.

If your client has been seeing major gains at the gym, adding an extra training session (or three), or increasing their workout intensity or training load, don’t ignore a potential symptom of overtraining. 

For example, if they suddenly feel fatigued, have a notable decreased performance, can’t get their heart rate to recover in the usual amount of time, or just feel “off,” note it. They can be doing too much without enough rest, proper nutrition, or hydration. 

Understanding the effects and symptoms of overtraining can help you and your client make smart decisions about a training session and overall exercise program. These informed decisions ensure that the many effects of overtraining don’t hinder their progress. 

Use this overtraining recovery guide to keep your clients healthy and strong, whether they’re with you in the gym or doing their programs.

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What is Overtraining?

Overtraining syndrome is a response to excessive exercise and not enough rest, hydration and nutrition. It can affect many systems in the body, including the nervous system, immune system, and endocrine system. 

There are a number of hypothesis about what causes overtraining, including decreased glycogen, decreased glutamine, increased tryptophan, excess oxidative stress, dysregulation of the hypothalamus, consistent microtrauma, and inflammation. The key is knowing whether your clients are doing too much, and if so, how to help them facilitate overtraining recovery so they can get back into their routine without any problems.

What Causes Overtraining

Overtraining can be caused by a wide range of stressors, from physical stress to lifestyle stress. It’s important to know the causes so you can avoid overtraining altogether when possible. Some of those causes include:

  • Too much exercise
  • Intensity
  • High frequency
  • Not enough recovery
  • Busy season of competition and training. 
  • Not enough sleep
  • High altitude
  • Illnesses
  • Heat injury
  • Eating patterns
  • Stressful job 

Many of these factors work together to create a perfect storm of overtraining.

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Signs of Overtraining

Cortisol levels rise when your client overtrains. This can cause the breakdown of muscle tissue because cortisol is catabolic. There is also a decrease in testosterone and an increase in cortisol, both of which can cause catabolic effects. 

As such, overtraining can cause the muscles to be depleted of essential energy reserves, leading to more dangerous symptoms. 

Often a symptom of overtraining occurs when it’s too late, and you have already reached overtraining. There are physiological, performance, and even psychological effects of overtraining. 

These symptoms include, but are not limited to:

  • Decrease in performance
  • Sluggishness
  • Chronic fatigue
  • Prolonged time to recover
  • Possible injuries
  • Unintentional weight loss
  • Headaches
  • Insomnia
  • Feeling of heavy legs
  • More frequent infections and illnesses
  • Elevated heart rate
  • Depression 

As you can see, overtraining doesn’t just affect the body but also the mind—something clients may not expect from hitting it too hard at the gym.

Parasympathetic vs. Sympathetic Overtraining Symptoms

Studies show that people who train more aerobically (like an endurance athlete) may have symptoms that affect the parasympathetic nervous system while those who exercise anaerobically (like a power athlete) may have symptoms that are seen in the sympathetic nervous system. 

The parasympathetic overtraining can be more severe and cause more symptoms, whereas the sympathetic. Consider the two potential areas to look at for overtraining recovery based on your clients’ activity preferences:

  • Parasympathetic symptoms are common in aerobic sports and include fatigue, depression, loss of motivation, and slower than normal heart rate. 
  • Sympathetic symptoms are more common with anaerobic overtraining and include fast heart rate, insomnia, high blood pressure and feeling of restlessness. 

The Overtraining Timeline

It’s important to note that overtraining doesn’t happen overnight. Most people reach a point of overreaching first. Overreaching can be a good thing for your client if there’s enough rest. Over time, however, overreaching, paired with other stressors add up and may cause a decrease in performance coupled with some signs of overtraining. 

When clients reach this point, it can take a few days to a few weeks to restore performance back. If clients transition from overreaching to overtraining, it can take months to recover and symptoms can be more severe. 

Is It Overtraining or Overreaching?

Sometimes fatigue is normal and makes sense after a tough training session, so how can you tell the difference between the two? Consider that overtraining can cause maladaptations. The chart below shows performance and training status on an upside down U. It makes sense that undertrained clients would have low performance, the left-hand side of the chart, and as they train more, begin to perform better. 

Once they’ve reached the zone of optimal training, the top of the U, but keep pushing harder, overreaching can occur, and their performance begins to decline. Once their body shifts into overtraining more, the bottom right-hand side of the U, their performance will begin to suffer significantly, and they may exhibit symptoms explained above.


Source: Plowman SA, Smith DL: Exercise physiology for health, fitness, and performance, ed 2, San Francisco, 2003, Benjamin Cummings.

Note that you can also rule out overtraining with medical testing aimed to test biomarkers of overtraining.  If the resources are available, this would be desirable if your client wants to see what areas may be affected and causing symptoms. 

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Help clients avoid overtraining 

You can’t always control your clients’ decisions or what they choose to do on their time away from the gym. But, part of your job is to educate them of the risks and give them the necessary tools and know-how to avoid overtraining. Here are some key tools to to aid in overtraining recovery and avoidance.

Proper Rest

The GAS Principle (general adaptation syndrome) encourages you to push clients to exhaustion to see results and build muscle. This principle also clarifies that to be successful and avoid overtraining, rest and recovery are necessary. There should be proper rest after intense exercise, which means making rest an important part of a client’s program is key. 

If you notice they’re overreaching, address and educate them on proper sleep habits and rest time. 

In addition, help your clients develop a routine that supports the recovery process. Stretching, putting their legs up, icing, rolling out and active recovery days are all key to avoiding overtraining.

Correct Periodization

The general adaptation syndrome principle also alludes to the power of proper progression and periodization. Progression and periodization include allowing for adequate rest between sets. 

Be sure your training programs are driving them toward success using the right periodization and progression model for them—including keeping the right time between sets and workouts to optimize performance while reducing overtraining. 


Help your client understand and follow proper nutrition to avoid getting depleted after hard workouts. If you’re uncertain about the nutrition elements of their training program, consider investing in a health and fitness degree that includes nutrition training. Or, refer them to a nutritionist; a sports nutritionist can be especially supportive. 


Like proper nutrition, proper water intake is essential. Ensure your clients drink enough water, even when they aren’t training with you. Use this hydration guide to determine what your client needs based on their training style and needs.


Ensure your client is taking part in a wide range of activities, exercises, movements, and modalities to avoid too much microdamage to the same muscles. Remember, excessive microdamage leads to overtraining. This also combats boredom and can help them to stay motivated. 

Training Tracking

Journaling is a well-used strategy for clients to track their training, allowing them to notice when they may be doing too much. Have clients journal about each session, including how it felt, symptoms experienced after exercise, nutrition and hydration and any other details that can help you track progress and potential overreaching or overtraining. This also helps them to get familiar with the signs that suggest they may need to slow down or take more rest. 

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Don’t Ignore Overtraining Recovery

Incorporating proper rest and educating your clients can help with both overtraining recovery and avoiding overtraining in the first place. No one wants to be out of the gym for months due to something that can be avoided. So make overtraining prevention a priority. Your job as a health and fitness professional is to give clients the best results—and preventing and managing overtraining is a crucial element of doing that.

Knowing how the body responds to movement is what the study of exercise science covers. This field of study isn’t just limited to movement. It also covers nutrition, exercise psychology, and fitness business. And, an exercise science degree is in high demand for health and wellness-related positions.

People interested in exercise, nutrition, and a healthy lifestyle often choose a degree in exercise science to pursue their own passion and help others do the same. And, the Lionel University’s reputation makes it one of the most sought-after fitness degree programs available. 

As if history and reputation aren’t enough, people choose Lionel because you also earn a personal training certification and other fitness specializations as you go through your program. Just months after enrolling in one of the exercise science degree programs, you’ll earn a Master Trainer Certificate. This means you can start working and earning a living in the fitness industry before you even finish your degree! And, with the help of financial aid, earning your exercise science degree is even more of a possibility. 

Regardless of whether you’re pursuing an associate’s degree, bachelor’s degree, or master’s degree, studying at Lionel is an easy choice.

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