There is much written about runners and athletes overtraining, and although everyone probably has some idea about what it is, a lot of people have different ideas about the causes, symptoms, how to monitor it and prevent it, and even whether it is a good thing or not.

The term overtraining is used in a variety of ways and is commonly used as a verb to indicate “performing too much training”. Saying “I am overtrained“, in this context, means “I have trained too much”. However, scientists tend to use the term overtraining to indicate a situation where a runner or athlete suffers from underperformance and there is no obvious reason to explain this.

Usually, the runner or athlete has tried to recover more with no success and/or to train harder with no success.

The underperformance is accompanied by a host of symptoms. These symptoms are diverse and highly individual and because of the complex nature of the symptoms the term ‘overtraining syndrome’ is often used. In a review article ‘Does overtraining exist?’ that Dr Shona Halson and I wrote several years ago, we defined overtraining or the overtraining syndrome, not on the basis of the decreases in performance or the symptoms but the duration of the recovery, which can be seen in the figure below.

Fatigue, overreaching and overtraining

At the lower end of the scale a drop in performance can simply be down to fatigue, running too many miles for example, and in these cases, recovery can just take a day or two. Extreme fatigue, often referred to as overreaching, usually occurs during a planned program of hard training or a training camp, and after sufficient recovery (up to two weeks), you typically see improvements in performance as the result for the hard effort.

However, it is a thin line between overreaching and overtraining, and this can develop into overtraining syndrome. This can be difficult to recover from, and could even mean the end of a season or even the career of a runner or athlete.

Now we have a better idea of the definition of overtraining, it is important to discuss the symptoms and causes.

Symptoms of overtraining

It is important to note that the most important symptom of overtraining (or overreaching) is decreased performance, without a clear reduction in performance, overtraining cannot be present.

Overtraining can be fatigue related, this includes chronic muscles soreness, decreased aerobic capacity and a runner or athletes being unable to complete a workout.

Heart rate: Increases in heart rate while resting or sleeping can also be indications of overtraining or irregular heart palpations.

Immune Health: During overtraining, your immune system can also be affected, this includes frequently suffering from colds, chest infections and longer recovery times from other sicknesses.

For more on immune health see, ‘how immune health can affect a runner’s performance‘.

Mood: Behaviour and changes in mood can also provide a good indication of overreaching or overtraining. These are easy symptoms to pick up on, especially for people that surround the runner or athlete.

It is common to see those affected becoming irritable and show signs of depression when training load is dramatically increased.

Sleep: Over symptoms, which can be seen in the above figure include sleep disturbances and insomnia, and loss of appetite in combination with weight loss.

Causes of overtraining

While increasing your training and running volume can be great stressors to the body and mind, there are many other in our lives, including; work, home environment, family, team mates, and pressures to perform to name a few.

When all of these stresses, including training, are combined, the toll on the body and mind may lead to the development of overtraining symptoms and decreases in performance.

Consider the example of the following runner. Our runner is performing identical training to the previous years and was always able to cope without any issues. However, this year, because of stresses with family, the overall stress load became too much and performance has been deteriorating in combination with significant mood changes.

The runner did not recognise the impact of the family stresses and responded to the lack of performance improvement by training harder. This made symptoms worse, not better. Overtraining should be seen as a balance between ALL stresses on one side and the ability to cope with these stresses on the other side.

How to prevent overtraining

To prevent overtraining, you need to manage all stresses, some may be out of your control but the main one that you can adjust is your training. You can try decreasing your mileage or the intensity workouts for a period of time to try and manage the other stresses the best you can.

You must also work on ways to help the body cope better with the causes of overtraining, such as building in more recovery time and making use of relaxation techniques, perhaps even work with a sports psychologist.

The main lesson for coaches and self-coached runners and athletes is to pay attention to the sum of all stresses and causes in order to find solutions to improving recovery. At the same time, it is important to make sure we are not dealing with a situation of undertraining. When undertraining, improving recovery and rest will have little or no effect.

Also especially at the elite level, careful ‘monitoring’ must be in place of the stresses (training and other causes) as well as the symptoms of overtraining.

About the author:
Asker Jeukendrup is a Professor of Exercise Biochemistry and Director of Mysportscience. He has published extensively on the topic of sports nutrition and acts as a consultant to many elite and not so elite athletes all over the world. He is also a keen runner and triathlete. You can contact Asker on twitter or