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Overtraining: Why It Happens, What It Looks Like, and What to do About It

overtraining symptoms signs

By Becky Arturo

It is no secret that training for a triathlon requires a lot of hard work and dedication. However, training volume needs to be increased carefully and methodically in terms of both time and intensity in order to make the appropriate physiologic adaptations to meet the demands of your event while avoiding potential negative consequences. 

There is a point where too much training time or intensity with insufficient rest and recovery can become detrimental to an athlete’s health and performance. At high severity, this is known as overtraining syndrome, and it is a serious problem for endurance athletes. 

Overtraining syndrome can lead to decreased performance, increased risk of injury, decreased immune function, mood disturbances, and negative effects on an array of other body systems. 

Why does overtraining syndrome occur?

Exercise stimulates a stress response in your body. With appropriate rest and recovery, your body responds to this stress and adapts over time to meet the demands of the activity that caused the initial stress. This is known as functional overreaching. 

However, your body requires rest and recovery time to adapt to the stress of training. Without adequate rest, functional overreaching can easily become “nonfunctional overreaching” with side effects such as decreased performance and fatigue. With chronic accumulation of stressors, this can then become full-blown overtraining syndrome, which can take months to even years to fully recover from.

The concept of functional overreaching is well accepted and understood in terms of muscular strength gains. When you stress your muscles with activities such as strength training, hill climbing, or sprinting, you are actually causing a breakdown of muscle tissue on a microscopic level. 

Your muscles then go through an inflammatory process to heal and recover with slightly larger or stronger muscle fibers. If you interrupt this inflammatory and recovery process with too much stress too soon, you are likely causing more damage than growth due to the lack of ability for the muscles to repair themselves.

Similarly, when you stress your cardiovascular system, excessive oxidative stress causes muscle damage and fatigue of multiple systems. While the exact physiologic mechanism of overtraining syndrome is not well understood, we do know that it is highly connected to inadequate rest and recovery on a repeated basis or too quick of progressions in training programs. 

Signs and symptoms of overtraining can include:

  • Excessive fatigue, even after adequate rest
  • Frequent illnesses, colds, or infections
  • Mood changes such as anxiety, depression, irritability, restlessness, or agitation
  • Heavy, sore, stiff muscles on a more frequent basis and after workouts that don’t usually make you that sore
  • Sleep changes such as insomnia or awakening unrefreshed 
  • Elevated or reduced resting heart rate compared to your normal
  • Elevated or reduced heart rate during exercise or elevated RPE at an equal pace compared to baseline
  • Decreased performance even though you are training a lot
  • Difficulty concentrating or lack of motivation
  • New onset of irregular menstruation in females
  • New onset of anemia
  • Changes in appetite or onset of disordered eating

We all have experienced some of these symptoms from time to time due to an array of potential life stressors, or even briefly due to nonfunctional overreaching in our training. 

However, if any of these symptoms become persistent, or if you are experiencing multiple of these symptoms or any symptoms on a chronic basis, it is essential to take a step back, reassess your training plan, and increase your rest and recovery time significantly.

Tips to avoid overtraining:

  • Prioritize appropriate rest and recovery. Rest is essential to a proper training plan. Without rest and recovery, you cannot adapt to the stress of training.
  • Listen to your body. If you think you are too sore or tired for a harder workout then you probably are. Opt for either a complete rest day or an active recovery day, such as a walk or an easy and short swim, bike, or run.
  • Get adequate sleep. Everyone needs a slightly different amount of sleep, but if you aren’t feeling well-rested most mornings, you may need to add some time for sleep.
  • Fuel your body properly. When participating in such an intense training regimen, it is vital to have a well-balanced diet with enough carbohydrates, proteins, and fats to support your training.
  • Increase your training gradually in terms of both intensity and duration of workouts.
  • Warm-up and cool down appropriately for each workout to allow your muscles to be prepared for the demands of the activity and to initiate appropriate recovery immediately after your workout ends
  • Stretch and perform dynamic mobility exercises regularly
  • Gradually incorporate strength training in your training regimen to help your muscles be able to keep up with the demands of your training.

What to do if you notice signs or symptoms of overtraining:

  • Back off the intensity, frequency, and duration of your workouts. While you do not need to immediately stop all exercise, your training volume should be decreased significantly. Think like a taper week in terms of volume and intensity and then modify from there.
  • Try to only do workouts you will truly enjoy. The workout itself should not induce psychological or emotional stress.
  • Reassess in a few weeks and seek medical guidance if symptoms do not resolve 

Overtraining is a serious problem for endurance athletes that comes with significant consequences. Therefore, it is an important topic to be educated about. It’s essential to listen to your body and get adequate rest and recovery. Progression of the intensity and duration of workouts should be done gradually with training blocks and step-down weeks scheduled. With proper training and adequate recovery, you can reach your performance goals safely and effectively without running the risk of overtraining.


  1. Weakley J, Halson SL, Mujika I. Overtraining Syndrome Symptoms and Diagnosis in Athletes: Where Is the Research? A Systematic Review. International Journal of Sports Physiology and Performance. 2022;17(5):675-681. Doi:
  2. Kreher JB, Schwartz JB. Overtraining Syndrome. Sports Health: A Multidisciplinary Approach. 2012;4(2):128-138. Doi:
Becky Arturo
Becky Arturo
Endurance Coach, Physical Therapist at Weights and Plates Endurance | Website

Becky Arturo is the co-founder of Weights and Plates Endurance Coaching. Becky Arturo received her doctorate degree in physical therapy and started practicing as a sports and orthopedic physical therapist in 2019. She is also a certified strength and conditioning specialist as well as a USA Triathlon certified coach. Learn more about Becky

Nicholas Fischer
Nicholas Fischer
Endurance Coach, Registered Dietitian at Weights and Plates Endurance | Website

Nicholas Fischer has been a registered dietitian since 2012 and offers over a decade of experience working with endurance athletes. Nicholas has spent time coaching and providing nutrition education for the Pittsburgh Marathon, USA Cycling, and multiple other cycling and running teams around the country. Learn more about Nicholas