Evaluation of pharmacological aids on physical performance after a transmeridian flight.
OBJECTIVE
The purpose of this study was to evaluate physical performance (static and dynamic) of U.S. Air Force reservists after an eastbound air travel across seven time zones and to estimate the pharmacological aids slow-release caffeine and melatonin versus placebo in attempt to overcome the decline in performance.


METHODS
27 American volunteers were randomly divided into three groups: caffeine 300 mg, melatonin 5 mg, and placebo (lactose capsules). Two days before the flight and 10 d after, three tests were performed: hand grip strength test (static performance), squat jump test (maximal height), and multiple jump test (power and endurance). All measures were repeated twice a day: morning and afternoon.


RESULTS
In placebo conditions, the static performance of the dominant hand decreased significantly during the first three mornings and tended to decrease the fourth morning. Simultaneously, the caffeine group's static performance increased significantly, whereas the melatonin group maintained its levels. No significant differences were observed the afternoons. No statistical differences appeared for the nondominant hand in the mornings or afternoons. Dynamic capacities presented no significant degradation after the travel. In the placebo group, for the squat jump test, performance increased from the fourth day. No real explanation can be given about this result.


CONCLUSIONS
We demonstrated that slow-release caffeine and melatonin might be used to compensate for jet-lag troubles and particularly for the static physical performance decrease. The slow-release caffeine seems to be the best treatment, but its effects are only demonstrated on previously damaged performance. These preliminary results need further investigation, but we are the first to report a beneficial effect of slow-release caffeine and melatonin on physical performances after jet-lag.
Institut de Médecine Aérospatiale du Service de Santé des Armées, B.P. 73, 91223 Brétigny-sur-Orge Cedex, France. dlagarde@imassa.fr
D
D
Lagarde
B
B
Chappuis
P F
PF
Billaud
L
L
Ramont
F
F
Chauffard
J
J
French
D000328:Adult; D000704:Analysis of Variance; D000975:Antioxidants / Q000627:therapeutic use*; D002110:Caffeine / Q000627:therapeutic use*; D000697:Central Nervous System Stimulants / Q000627:therapeutic use*; D002940:Circadian Rhythm / Q000187:drug effects; D003692:Delayed-Action Preparations / Q000627:therapeutic use; D004311:Double-Blind Method; D005080:Exercise Test / Q000379:methods; D005260:Female; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D020179:Jet Lag Syndrome / Q000517:prevention & control*; D008297:Male; D008550:Melatonin / Q000627:therapeutic use*; D008875:Middle Aged
D000975:Antioxidants; D000697:Central Nervous System Stimulants; D003692:Delayed-Action Preparations; D002110:Caffeine; D008550:Melatonin