REF-1581 · Lucía et al., 2001 · British Journal of Sports Medicine · Paper · PubMed · Free full text

Over the three weeks of the 1999 Vuelta a España, nine professional cyclists showed falling morning cortisol and testosterone and a falling melatonin metabolite in morning and evening urine; the authors suggest that the resting output of the adrenal glands, testes and pineal gland may turn down after many hard days in a row. Nothing in the abstract ties the fall to worse racing, poorer recovery or illness, the abstract describes no control group, and numbers are given only for the melatonin metabolite. From the abstract

Main caveat: Nine riders, one race, no control group described: racing load, travel, sleep, weather and food may all have changed at the same time, and none is reported in…
limited, mixed evidenceMeasured on elite to world-class athletes

Lucía and colleagues followed nine professional riders through the 1999 Vuelta a España, a three-week stage race.

Before the start and at the end of each week they took morning blood for testosterone, luteinising hormone (LH), follicle-stimulating hormone (FSH) and cortisol, and collected morning and evening urine for 6-sulphatoxymelatonin (aMT6s), the main breakdown product of melatonin.

At the end of each week one urine sample of the day held significantly more of the melatonin metabolite than the other; the abstract says levels rose during the day, read here as evening above morning, though it does not label the pair. Both the morning and the evening values fell significantly over the race.

Morning cortisol and testosterone fell over the race in a similar way, with no values reported. The authors suggest that the resting activity of the pineal gland, the adrenal glands and the testes may be lower after consecutive days of long, hard exercise.

Participants

n = 9 professional cyclists, men (MEDLINE indexing), 28 ± 1 yr, VO2max 75.3 ± 2.3 ml/kg/min (mean ± SD), all racing the 1999 Vuelta a España.

Protocol

Sampling points: t0 before the race; t1, t2 and t3 at the end of weeks one, two and three.
Morning serum: testosterone, LH, FSH, cortisol.
Urine: aMT6s in the morning and in the evening at each point.

Key Results

Urinary aMT6s (ng/ml)t1t2t3
Higher value of the pair (read as evening)1091 (33)955 (19)647 (61)
Lower value of the pair (read as morning)683 (68)473 (53)337 (47)
Morning serum cortisol and testosterone fell over the race, in "a similar pattern" (the abstract's words) to the melatonin metabolite below. No values are given, and whether each fall was significant on its own is not stated separately.
Both morning and evening aMT6s fell significantly over the race.
The abstract does not label which value of each pair is morning and which is evening. It says the rise was significant (p < 0.01) and came "during the day after each stage", read here as the evening value standing above the morning value at t1, t2 and t3 (inference from that wording). The bracketed values are as printed, and the abstract does not say whether they are SD or SEM. t0 values are not given.
LH and FSH were measured, but the abstract reports no result for them.

Practical Application

In nine world-class riders, morning cortisol and testosterone and a melatonin metabolite fell over the three weeks of a Grand Tour, and nothing in the abstract links that fall to worse racing or illness. To "my testosterone or cortisol dropped during a camp or a hard block — am I overtrained?": a fall like this was seen across nine world-class professionals during a Grand Tour, and the abstract does not say whether any of them were overreached, so this study cannot tell a harmless fall from a harmful one; on its own such a fall is not a diagnosis.Overtraining is judged by performance and by ruling out other causes, not by one hormone (PHYS-27, REF-206).
The abstract reports no test of whether riders with a larger fall recovered or raced worse. A link between these hormones and recovery capacity is a hypothesis, not a finding of this paper.
Read a hormone like any marker: within the person, as a trend, next to how training and racing are going (PHYS-44, SYNTH-30).
Before reading a falling testosterone as overload, rule out under-fuelling, which turns the same hormone down in men (PHYS-32). This abstract reports no food intake or body-mass data (MEDLINE indexes the record under Body Weight, so the full text may report body mass), so it neither shows nor excludes that.
Inference, not tested here: during a stage race, sleep, transfers and the time of sampling shift together with load, so a single hormone test taken outside a fixed routine is hard to read.

Limitations

Nine riders, one race, no control group described: racing load, travel, sleep, weather and food may all have changed at the same time, and none is reported in the abstract, so the cause of the fall cannot be separated.
Hormone concentrations only; no performance, recovery or illness outcome was related to them.
The abstract gives numbers only for the melatonin metabolite; testosterone and cortisol are described in words, and LH and FSH results are not reported.
How sampling times were held against stage start times and transfers is not described in the abstract.
Men only, one Grand Tour in 1999.
Written from the abstract and record metadata only (full text not read).
How this entry was checked and changed
Why this level

elite case series, n = 9, which is B by design (as for REF-884); lowered because the outcomes are hormone concentrations only (markers, not performance or health), racing, travel, sleep and food may all have changed together (none is reported in the abstract), so the cause of the fall cannot be isolated, and the abstract gives no numbers for testosterone or cortisol and no result for LH or FSH