July 22, 2013
Overtraining - Conclusion
Over the past month I’ve outlined what exercise scientists consider as “overtraining”.  If you’ve been following these posts you have probably come to the conclusion that overtraining does not exist.  I would have to agree with that due to the lack of clear evidence of support on the topic.  Although I could not put it so elegantly as CT Fletcher, I must admit that the human body does possess a high capacity to adapt to any stimulus that it is given.  An adaptation to training can occur even after one bout of resistance exercise (known as the repeated bout effect).  Most of you spend the majority of your day sitting at sedentary jobs or in classrooms.  To have a truly taxing workout for 1-2 hours per day seems implausible to hinder recovery and performance. The problem is that there are too many variables (nutrition, sleep, mood, etc) to consider to even have a well-controlled study on overtraining.  Of course, you must have proper rest and adequate nutrients to continue performing at a certain level.  Lacking those two variables alone could be the culprit in the decrements you see with training and not the actual training itself.  The best available source for coaches to try to diagnose overtraining is in this checklist provided by the ACSM review.  I hope that you were able to take away the recent standpoint on overtraining in the scientific community and understand the lack of concise and consistent data in support of it.

Overtraining - Conclusion


Over the past month I’ve outlined what exercise scientists consider as “overtraining”.  If you’ve been following these posts you have probably come to the conclusion that overtraining does not exist.  I would have to agree with that due to the lack of clear evidence of support on the topic.  Although I could not put it so elegantly as CT Fletcher, I must admit that the human body does possess a high capacity to adapt to any stimulus that it is given.  An adaptation to training can occur even after one bout of resistance exercise (known as the repeated bout effect).  Most of you spend the majority of your day sitting at sedentary jobs or in classrooms.  To have a truly taxing workout for 1-2 hours per day seems implausible to hinder recovery and performance. The problem is that there are too many variables (nutrition, sleep, mood, etc) to consider to even have a well-controlled study on overtraining.  Of course, you must have proper rest and adequate nutrients to continue performing at a certain level.  Lacking those two variables alone could be the culprit in the decrements you see with training and not the actual training itself.  The best available source for coaches to try to diagnose overtraining is in this checklist provided by the ACSM review.  I hope that you were able to take away the recent standpoint on overtraining in the scientific community and understand the lack of concise and consistent data in support of it.

June 12, 2013
Overtraining - Physiology & Immune System

Several physiological factors have been proposed that could relate to overtraining syndrome.  It seems the most plausible one is a reduced maximal heart rate but studies suggest this is not a valid tool to measure OTS due to inconsistent results.

Sustained periods of intense training leads to decreases in innate and adaptive immunity.  Depressed immunity typically is said to occur for athletes at the end of the season or during the most intensive periods of their training.  The only evidence that exists for a decrease in immune function in athletes experiencing OTS is anecdotal.

In regards to resistance training, when excessive volumes of max loads are used, maximal muscular strength is one of the last performance measures to be negatively affected.  Rather, high speed (ie. sprinting) and power are the first types of performance to be affected.

There is no evidence that OTS can be treated.  Rest and very light training seem to be the only agents capable of effecting recovery.  It is generally recommended that athletes should have one passive rest day each week.  Trying to prescribe an exact amount of hours of sleep per night is difficult.  Therefore, a good starting point is to advise athletes to sleep for the amount of time required to feel wakeful during the day.

May 22, 2013
Overtraining - Psychology

When scientists use psychological questionnaires about athletes’ moods there was a consistent reporting of an increase in negative mood states (tension, depression, anger) and a decrease in vigor during periods of vigorous training.  This is shown in a dose-response relationship, meaning that the longer the periods of intense training the more the athlete will report these negative mood states.  As little as 2 days of intense training can increase these negative moods and currently there are no differences in the mood responses reported between male and female athletes.

Of course it is difficult to decipher whether these negative moods are a result of the training or hardships from social situations.  Therefore, some researchers have developed a sport specific scale to use rather than the typical psychological questionnaires called a Training Distress Scale (TDS).  You can find a spreadsheet of this scale here.  The TDS was shown to be more accurate in identifying overtraining than the typical psychological scale.

A new tool that researchers are using to diagnosis overtraining syndrome is a psychomotor speed test, which measures the cognitive factors of the athlete (memory & concentration).  This test could simply be a reaction time test.  Reaction times have been reported to decrease in athletes when they increase the intensity of their training for several weeks.  These studies lead us to believe that central fatigue (a tired brain) is possibly the most early predictor of overtraining.

May 15, 2013
Overtraining - Biochemistry & Hormones

The most consistent overall finding in endurance and strength-trained athletes who have OTS is a decrease in the maximal lactate concentration  while submaximal values are unaffected or only slightly reduced.  Glutamine levels are often toted as another possible marker to indicate excessive training stress.  However, several problems exist with biochemical testing of overtraining:

  • Lactate differences can be subtle and depend on the type of exercise test used.
  • No lactate changes are reported in strength athletes.
  • Glutamine may decrease with excessive training but low levels are not a consistent finding in OTS.

At first, scientists tried to measure the testosterone/cortisol ratio as a marker of overtraining.  This is not possible because this ratio only indicates the actual physiological strain of training.  Furthermore, during rest days in endurance-trained athletes, 24 hour cortisol secretion is normal and even comparable to levels of sedentary individuals.  Problems exist with hormonal testing as well:

  • Many factors other than exercise affect blood hormone concentrations such as stress or food intake.
  • In females, it depends also on the menstrual cycle.
  • Different hormones are released depending on the modes of training (endurance vs. resistance).
  • Diurnal and seasonal variations of hormones.

May 8, 2013
Overtraining - Diagnosis, Prevalence, & Assessment

It is noted that there is no definitive way to identify overtraining syndrome (OTS).  The only way a coach can do so is by eliminating all other factors that could be causing these symptoms.  Once all of the other factors are eliminated, one can then diagnose OTS.  The only clear sign is a decrease in performance during competition or training. Currently, there are no simple diagnostic tests to diagnose overtraining and the theories regarding what triggers it are speculative at best.

Taking into account the overlap and still unclear guidelines of overreaching/overtraining, I will now list for you some of the statistics on the prevalence of OTS.

  • One survey listed a rate of approximately 10% in collegiate swimmers and other endurance athletes.
  • For elite runners, 60% of females and 64% of males indicated experiencing OTS with numbers being 33% in non-elite adult runners
  • A recent longitudinal study reported a rate of 29% in age-group swimmers
  • 91% of US collegiate swimmers that reported OTS a first time went on to experience it a second time or more.

To assess OTS, several studies have listed it as being the sum of multiple life stressors, such as training, sleep deprivation, environmental stress, work pressure, and interpersonal problems.  Scientists are still looking for a biomaker (in the blood) to measure and determine the existence of OTS.

May 1, 2013
Overtraining - Definition

We know that there must be a balance between appropriate training stress and adequate recovery.  Otherwise, this leads to what exercise scientists define as overreaching.  Overreaching is an accumulation of training and/or non-training stress resulting in short-term decreases in that capability to perform with or without related physiological and psychological signs and symptoms of maladaptation.  Restoration of performance capacity could take several days to several weeks.  The difference between this and overtraining is that overtraining is long-term, in which restoration of performance capacity can take several weeks or months.  We are looking at solely a time difference between the two.  

An example of an athlete who is overreaching would be one that goes to a training camp.  The intensity level of the camp is normally very vigorous, which would lead to a temporary decline in performance accompanied later by overall improvement of performance.  This can also be noted as functional overreaching.  When it gets to the extent of not helping the athlete improve their performance capacity, it then can be described as non-functional overreaching because it leads to stagnation or decreases in performance which will require several weeks or even months to recover.

Overtraining syndrome is considered a syndrome because it takes in to account not just exercise as the main factor but also inadequate nutrition, illness, psychosocial stressors, and sleep disorders.

Below is an example of the difference stages of training and how they relate to overreaching and/or overtraining.

April 24, 2013
Joint Consensus Statement of the European College of Sport Science & the American College of Sports Medicine on Overtraining Syndrome

For training to be successful, it must involve an overload on the body but also avoid the negative outcomes of this overload.  For the upcoming month up until I leave for the 2013 ACSM conference in Indianapolis (holla atcha boy if you’re going), I will outline for you the mutual American and European “consensus statement” on the Prevention, Diagnosis, and Treatment of Overtraining Syndrome.  This will consist of the following sections:

  • Definitions
  • Diagnosis
  • Prevalence
  • Assessment of overtraining
  • Biochemistry
  • Performance testing
  • Psychology
  • Physiology
  • Immune system response
  • Conclusions

I hope to make clear for you the true scientific evidence on how to diagnosis overtraining and what actually is happening molecularly in the body to bring about these symptoms.  If you are a performance coach hoping to better your athletes or someone who wishes to have all the myths surrounding overtraining debunked I promise you the next several posts will be good reads.  Until then, all the best!

Nick