Is it Really a Useful Index for Monitoring Training Follow-Up? Rouveix M, Duclos M, Gouarné C, Beauvieux MC, Filaire E. The 24 h Urinary Cortisol/Cortisone Ratio and Epinephrine/Norepinephrine Ratio for Monitoring Training in Young Female Tennis Players. Int J Sports Med 2006; 27: 856 - 863

Dear Editors

I read with great interest the paper of Rouveix et al. [[14]] who monitored training and excretion of urinary free cortisol (UFC) and cortisol (UFCn) in young female tennis players. They considered, similar with other recent studies [[1], [6], [8]], the ratio of UFC/UFCn as a sensitive index of renal 11β-hydroxysteroid dehydrogenase type 2 activity reflecting mineralocorticoid action in healthy males and females. They concluded that “our results reveal that an increase in overnight urinary C/Cn ratio and a decrease in E/NE ratio are concomitant with alterations in mood state and performance, all these parameters being associated with physical and psychological stress. An increase in 24 h C/Cn and a decrease in E/NE ratio along the training period may be predictive markers of tiredness and decreased performance” (p. 862). I believe there are shortcomings in their study that make the interpretation of their results difficult or even impossible. These limitations included (i) Rouveix et al. [[14]] reported on the 24-hour UFC/UFCn ratio in the title as well as in the text - on the other hand, their conclusion refers to overnight urines (the last paragraph of the summary); (ii) they stated that “the following morning, diuresis was noted” (p. 859). What did they mean? It should not be expected that the volume of overnight or morning urine is unusually large or diluted. The third and most serious limitation of their investigation is that they ignored the possible influence of variation in urine volume, although is it now well documented that the excretion of UFC [[4], [5], [13]] and UFCn [[2], [3], [4]] in human and of that of 17-hydroxycorticosteroids in laboratory animal species [[9], [11]] depends on urine volume.

In conclusion, attention to the relationship between urine volume and urinary free corticosteroid excretion is crucial for data interpretation and for reducing the uncertainty associated with measures of urinary free corticosteroids. Then, the UFC/UFCn ratio may be used as a reliable index to monitor functional changes of the 11β-hydroxysteroid dehydrogenase type 2, which may provide new insights into the adaptation of the adrenal gland to variations in training loads.

References

• 1 Atlaoui D A, Duclos M, Gouarné C, Lacoste L, Barale F, Chatard J-C. The 24-h urinary cortisol/cortisone ratio for monitoring training in elite swimmers.  Med Sci Sports Exerc. 2004;  36 218-224
• 2 Fenske M. How much “urinary cortisol” is really cortisol during water diuresis in normal individuals.  Clin Chem. 2004;  50 1102-1104
• 3 Fenske M. Thin-layer chromatography-competitive protein binding assay for cortisol and cortisone, and its application to urines of healthy men undergoing water diuresis.  Chromatographia. 2006;  63 383-388
• 4 Fenske M. Urinary free cortisol and cortisone excretion in healthy individuals: influence of water loading.  Steroids. 2006;  71 1014-1018
• 5 Friedman T C, Papanicolaou D A. Comment on high urinary free cortisol excretion in a patient with psychogenic polydipsia.  J Clin Endocrinol Metab. 1998;  83 3378
• 6 Gouarné C, Groussard C, Gratas-Delamarche A, Delamarche P, Duclos M. Overnight urinary cortisol and cortisone add new insights into adaptation to training.  Med Sci Sports Exerc. 2005;  37 1157-1167
• 7 Gutenbrunner C, Schreiber U. Circadian variations of urine excretion and adrenocortical function in different states of hydration in man.  Progr Clin Biol Res. 1987;  227 A 309-315
• 8 Jerjes W K, Peters T J, Taylor N F, Wood P J, Wessely S, Cleare A J. Diurnal excretion of urinary cortisol, cortisone, and cortisol metabolites in chronic fatigue syndrome.  J Psychosom Med. 2006;  60 145-153
• 9 Kalant N. Adrenal function in alloxan diabetes.  Am J Physiol. 1955;  182 503-506
• 10 Lewicki S, Nowicki M, Vescei P. Effect of sodium restriction on urinary excretion of cortisol and its metabolites in humans.  Steroids. 1998;  63 401-405
• 11 Lazo-Wasem E A, Hier S W. Relationship between adrenocorticosteroid excretion to urine volume in the guinea pig.  Endocrinology. 1958;  62 308-312
• 12 Lundberg U, Forsman L. Consistency in catecholamine and cortisol excretion patterns over experimental conditions.  Pharmacol Biochem Behav. 1980;  12 449-452
• 13 Mericq M V, Cutler Jr G B. High fluid intake increases urine free cortisol excretion in normal subjects.  J Clin Endocrinol Metab. 1998;  83 682-684
• 14 Rouveix M, Duclos M, Gouarné C, Beauvieux M C, Filaire E. The 24 h urinary cortisol/cortisone ratio and epinephrine/norepinephrine ratio for monitoring training in young female tennis players.  Int J Sports Med. 2006;  27 856-863