Athletes ingest melatonin in an attempt to improve sleep quality or alleviate symptoms
of jet lag after transmeridian travel. It is not known whether there are residual
effects of this hormone on physical performance in fit subjects. After a sample size
estimation involving a meaningful effect on performance of 5 %, five milligrams of
melatonin or placebo were ingested by twelve physically-active subjects before sleep
in a double-blind experiment. The following morning, subjective sleep quality (latency
and maintenance) were measured together with intra-aural temperature, grip strength
of the left and right hands, and time to complete a 4 km time trial on a cycle ergometer.
The subjects also rated perceived exertion during the latter test. The null hypothesis
of no effect of melatonin on either subjective sleep quality or physical performance
measured the morning after administration could not be rejected on the basis of our
observations (P > 0.30). The mean differences between treatments were less than 1
% for the strength tests and time trial performance. The confidence intervals for
these differences for left and right grip strength and the cycling test were - 2.1
to 2.8 kg, - 3.1 to 2.7 kg and - 3.0 to 4.5 s, respectively. In conclusion, it is
unlikely that 5 mg of melatonin would have any meaningful effects on physical performance
in the morning after fit subjects ingest the hormone. There was also little evidence
that it improves sleep quality in this population. Further research is needed concerning
the effects of daytime and nighttime admistration of melatonin on performance, in
both situations of normal and disturbed sleep.
Key words:
Hypnotics, chronobiotics, residual effects, exercise.
References
- 1
Arendt J, Deacon S.
Treatment of circadian rhythm disorders - melatonin.
Chronobiol Int.
1997;
14
185-204
- 2
Argyriou A, Prast H, Philippu A.
Melatonin facilitates short-term memory.
Eur J Pharmacol.
1998;
349
159-162
- 3
Atkinson G, Nevill A.
Statistical methods for assessing measurement error (reliability) in variables relevant
to sports medicine.
Sports Med.
1998;
2
217-238
- 4
Atkinson G, Nevill A, Edward B.
What is an acceptable amount of measurement error? The application of meaningful 'analytical
goals' to the reliability analysis of sports science measurements made on a ratio
scale.
J Sports Sci.
1999;
17
18
- 5
Bland J M, Altman D G.
Measuring agreement in method comparison studies.
Statist Meth Med Res.
1999;
8
135-160
- 6
Dollins A B, Lynch H J, Wurtman R J, Deng M H, Kischka K U, Gleason R E, Lieberman H R.
Effect of pharmacological daytime doses of melatonin on human mood and performance.
Psychopharmacology.
1993;
11
490-496
- 7
Fraschini F, Cesarani A, Alpini D, Esposti D, Stankov B M.
Melatonin influences human balance.
Biol Sig Recept.
1999;
8
111-119
- 8
Mendelson W B.
A critical evaluation of the hypnotic efficacy of melatonin.
Sleep.
1997;
2
916-919
- 9
Nickelsen T, Demisch L, Demisch K, Rademacher B, Schoffling K.
Influence of subchronic intake of melatonin at various time of day on fatigue and
hormonal levels: a placebo-controlled, double-blind trail.
J Pineal Res.
1989;
6
325-334
- 10
Rogers N L, Phan O, Kennaway D, Dawson D.
Effect of oral daytime melatonin administration on cognitive psychomotor performance
in humans.
Sleep Res.
1997;
26
212
- 11
Schwenk T L.
Psychoactive drugs and athletic performance.
Phys Sportsmed.
1997;
25
32-41
- 12
Waterhouse J, Reilly, Atkinson G.
Jet-lag.
Lancet.
1997;
35
1611-1616
- 13
Waterhouse J, Reilly T, Atkinson G.
Melatonin and jet lag.
Br J Sports Med.
1998;
32
98-99
Dr. G. Atkinson
Research Institute for Sport and Exercise Sciences
Liverpool John Moores University
Henry Cotton Campus
Webster Street
Liverpool L3 2ET
UK
Telefon: Phone:+ 44 (151) 2314-333
Fax: Fax:+ 44 (151) 2314-354
eMail: E-mail:g.atkinson@livjm.ac.uk
