What Causes Overtraining Syndrome and How to Prevent It

Big racers on road with trees in the background

Endurance training involves a shift in the duration, frequency, and intensity of training loads. The impact of short, high-intensity training versus longer, slower distance training has been studied and debated for decades among athletes, coaches, and scientists (Kreher, 2016). Endurance athletes frequently participate in persistently high volumes and intensities of practice to achieve a high level of performance without understanding that physiological adaptation occurs during rest periods following hard physical exertion (Montesano, Di Silvestro, Cipriani, & Mazzeo, 2019). Without maintaining a proper balance between training and recovery, complete regeneration cannot occur, and performance plateaus and will eventually decline resulting in the potential for overtraining syndrome.

What is Overtraining Syndrome?

There are two types of overtraining syndrome consisting of sympathetic and parasympathetic. Overtraining associated with the sympathetic form is characterized by increased sympathetic response and is more common in the anaerobic system dominant sports such as sprinting or soccer (Meeusen & De Pauw, 2019). The sympathetic nervous system is often associated with preparing the body for fast movements such as the fight or flight response. An athlete’s heart rate is elevated and glucose is released from the liver. Athletes who are suffering from sympathetic overtraining syndrome generally have increased heart rate and blood pressure, decreased appetite and body mass, sleep disturbance, along with irritability (Meeusen & De Pauw, 2019). 

Overtraining associated with the parasympathetic form is often associated with aerobic dominant and endurance sports (Meeusen & De Pauw, 2019). The parasympathetic nervous system is accountable for stimulating actions when the body is at rest, such as urination and digestion. Athletes who are suffering from parasympathetic overtraining syndrome generally have a decreased resting heart rate and resting arterial pressure, extended periods of sleep, and depression (Kreher, 2016). Many studies have demonstrated that endurance athletes, in particular, can present symptoms associated with both sympathetic and parasympathetic overtraining.

How Can Overtraining Syndrome be Prevented?

Overtraining syndrome can be prevented by manipulating variables from each training session and throughout training cycles to maximize physiological capacity over time. It is implicit for an athlete or coach to implement properly periodized training plans associated with individual athlete thresholds and goals. An athlete’s training volume should increase and decrease with training intensity. For example, an athlete would not want to complete a high-volume workout above anaerobic threshold back to back or continuously without appropriate amounts of rest. Recovery and rest days are as essential to an athlete as workdays in increasing performance and preventing overtraining syndrome.

Athletes do not train at the same duration or intensity for every training session. The variables are manipulated from day to day to maximize physiological capacity over time and stay healthy. Indeed, the former is wholly dependent on the latter. 


  1. Kreher, J. B. (2016). Diagnosis and prevention of overtraining syndrome: an opinion on education strategies. Journal of Sports Medicine, 7(1), 115-122
  2. Meeusen, R., & De Pauw, K. (2019). Overreaching and overtraining syndrome: Causes, prevention, and remedy. APA handbook of sport and exercise psychology, 2(1), 147-157
  3. Montesano, P., Di Silvestro, M., Cipriani, G., & Mazzeo, F. (2019,1). Overtraining syndrome, stress and nutrition in football amateur athletes. Journal of Human Sport and Exercise, 957-969

Kristen Hench

Kristen Hench, Ph.D., is a certified coach through USAT, USAT Para, ACE, USAC, ASCA, ASFA Yoga certified, and is a RRCA certified race director. She has trained beginner through elite athletes helping many to reach podium finishes as well as meet their personal goals in triathlon, running, track, and swimming. Kristen coaches adaptive sports with the USAF AFW2 program as a cycling coach and also works with a variety of able-body and parasport athletes through TRIMotion3. She enjoys helping children and youth get healthy, learn new life-long skills, and build confidence. She has coached internationally and was selected to coach in the 2018 and 2020 Invictus games. Kristen has also directed numerous family races and competed in several triathlons herself, including the Ironman distance events. She placed in the top three for her age group in the inaugural year of the Mountaineer Half Ironman and was one of the top swimmers in the 2004 Lake Placid Ironman. Besides triathlons, Kristen also enjoys marathons (with a PR of 3:15), triathlon, swimming, and a multitude of boot camp activities.