Tiredness is a common issue for dedicated athletes.
Acute fatigue associated with training is normal and expected to settle with appropriate recovery. When training and recovery are in balance for the athlete, optimal performance is the result. With excess physical or emotional stress and lack of adequate recovery, fatigue can accumulate.
The most common medical causes of tiredness are iron deficiency, viral infections, asthma-like conditions, medication, mood disturbance and endocrine conditions such as PCOS or RED-S. The determination of appropriate evaluation for these conditions is based on the specific points on history and physical examination to be carried out by a physician, ideally familiar with sport and exercise medicine.
The most common non-medical causes of tiredness in the athlete are inappropriate training plan, poor sleep, lifestyle stressors, inadequate macronutrient intake and suboptimal hydration. Review of the training history, sleep habits and nutrition may reveal factors contributing to tiredness. With regards to training, specifically, increase in volume, intensity and frequency of competition should be looked at. In terms of sleep, evidence indicates adults require at least 7 hours of sleep per night. Beyond sleep duration, quality can be assessed using an activity tracker or App. Nutrition history should focus on macronutrient deficiency and iron intake. Advice from a registered sports dietician is ideal.
Lifestyle issues come into play by impacting overall capacity. School, work, relationships and performance anxiety all draw on overall energy levels. There are scales and questionnaires that are commonly used to assess fatigue and stress levels. Examples include Profile of Mood States (POMS) and recovery-rest questionnaire (RESTQ-Sport). One needs to consider the role of a mood or anxiety disorder that is impacting function. When psychological issues become difficult to manage they create profound stress and energy drain. Evaluation for mood, anxiety and possible clinical eating disorder should be carried out by a health care professional trained in mental health.
Functional overreaching (FOR) refers to the acute fatigue that ensues after overload as a part of successful training. This is expected to resolve with appropriate recovery. When the balance between training stress and recovery is disrupted performance can deteriorate as training stress continues. This is called non-functional overreaching (NFOR). The differentiation between non-functional overreaching and frank overtraining syndrome (OTS) is typically made retrospectively based on the time required for resolution of symptoms. Functional overreaching typically resolves within days to weeks, nonfunctional overreaching within weeks to months and overtraining syndrome beyond a month.
Prevention of NFOR and overtraining syndrome should focus on prevention and early diagnosis. Prevention and early identification is based on logging training load and regular performance testing. GPS data can be utilized in monitoring load. Monotony in training should be avoided and one day per week should be a rest day. Sleep records are helpful. Reassessment of nutrition strategies should be undertaken.
Warning signs can be monitored for thru questionnaires or metrics such as morning heart rate, maximal heart rate and heart rate variability. In addition, athletes and coaches will note plateauing performance with increased effort and lack of finishing kick.
Another consideration in prevention is periodization of training and competition around known stressful timeframes such as exam period or significant life stressors.
The following can illustrate the body’s general response to stress.
For further in-depth reading on this topic see Kreher & Schwartz. Overtraining Syndrome: A Practical Approach.