Interpreting a Fatigue Profile in a State-Level Swimmer
A 16-year-old female swimmer trains 18 hours per week across nine sessions. Over four weeks her 100 m freestyle time trial has slowed from 62.0 s to 64.8 s, her resting heart rate has risen from 52 to 61 bpm, her sleep has fallen from 8.5 to 6.5 hours, and she reports feeling 'flat' in warm-ups but 'fine' once racing. Her coach wants to add a fifth week of high-intensity work before taper. A blood test shows ferritin of 18 micrograms per litre (laboratory reference 15-150) and haemoglobin within normal range.
1. Distinguish between the interpretations of 'overreaching' and 'non-functional overreaching' in this case, and state which is more likely.
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Functional overreaching is a short-term performance decrement followed by supercompensation after a few days of reduced load; the athlete typically still performs well in competition and recovers quickly. Non-functional overreaching involves a longer decrement (weeks to months), disturbed sleep, elevated resting heart rate and mood disturbance, and does not resolve with a brief rest. This athlete shows multiple systemic markers (sleep loss, resting heart rate up 9 bpm, performance down 2.8 s, subjective flatness) persisting across four weeks, which points toward non-functional overreaching rather than a planned functional overload. The key discriminator is duration plus the breadth of markers, not the time-trial result alone. Adding a fifth high-intensity week would likely deepen the deficit.
2. How should the ferritin result influence the decision?
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Ferritin of 18 is within the laboratory reference range but at the low end, and in endurance athletes a value this low is often considered suboptimal for iron availability even when haemoglobin is normal. It does not by itself explain a 2.8 s decline, and it does not justify a diagnosis. The appropriate action is to refer to a medical practitioner for assessment and dietary review while not treating the number as the sole cause. Importantly, the coach should not use the 'normal' flag to dismiss the broader fatigue picture, nor use the low ferritin to explain away sleep deprivation and training load. The judgement is that iron status is a contributing factor to monitor, not the primary driver.
3. Recommend a course of action for the next two weeks and justify it.
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Reduce training volume by roughly 40-50 per cent for 7-10 days while retaining some intensity to preserve feel, restore sleep to at least 8 hours, and remove the proposed fifth high-intensity week. Retain technique work and low-volume race-pace efforts so the swimmer does not lose speed. Monitor resting heart rate, sleep and a simple wellness score daily, and re-test the 100 m time trial after 10 days. If markers improve, resume a shortened build then taper; if not, extend the reduced-load period and escalate to medical review. The rationale is that the current presentation is consistent with accumulated fatigue, and the cost of one lost training week is far lower than the cost of a multi-month non-functional overreaching episode in a 16-year-old.