UMEM Educational Pearls

Apologies for the long pearl, I did not want to split this into 3 parts)

Disruptions in sleep and circadian rhythms (from travel across time zones and jet lag) are known to alter cognitive functions. Mood and complex mental performance tasks deteriorate faster than do simpler mental performance tasks.

An athlete’s circadian rhythms are believed to be optimal for performance in the early evening (reaction time to light and sound in the fastest). Interestingly, the evening is the time of day when most world records have been broken. However, activities that require fine motor control and accuracy (hand steadiness and balance) are best in the morning.

In the normal population, travel effects are seen in inattention and an increase in errors and injuries in the workplace.

Athletes who perform in international competitions immediately after time zone transitions demonstrate a decline in performance involving complex mental activities, with an associated feeling of lethargy and a general loss of motivation.

British Olympic athletes demonstrated a decrease in leg and back strength in addition to reaction time when traveling westward across 4 time zones. In the NFL, west coast teams consistently beat east coast teams in evening games.

Of course, this type of outcome data is multifactorial and travel effects likely are only one of many complex factors.

Treatment:

Full adaptation to the new time zone is NOT recommended for short trips (1 – 2 days), only for longer stays (> 3 days).

Nonpharmacologic: 

Preadaptation and bright light therapy: Remember that exposure to light is the primary cue for circadian rhythms. Bright light exposure in the mornings (after eastward travel) will advance the body clock, while exposure in the evenings (after westward travel) will delay it (Level B).

Shifting the sleep schedule 1 - 2 hours towards the destination time zone in the days preceding departure may shorten the duration of jet lag (Level B).

Strategic napping: Napping in the new time zone during typical sleep times in the destination time zone will delay adaptation. Power naps (20 minutes) may be helpful in decreasing daytime sleepiness in those with jet lag (Level B). The best time to nap (in flight or post flight) is nighttime in the destination time zone (Level B).

Pharmacologic:

Melatonin: Cochrane review concludes that it is safe and effective in both treating and preventing jet lag. It is recommended for adults traveling across 5 or more times zones; and may be effective for travel across 2 to 4 time zones. Take melatonin in the morning when traveling westward, and at the local bedtime when traveling eastward (Level B). Doses of 0.5 to 5mg were similarly effective. Melatonin taken in the evening and at higher doses are effective at inducing sleep (Level A).

Sleep aids:  Hypnotic sleep aids reliably induce insomnia secondary to jet lag. Benzodiazepines improve sleep quality but may cause a “hangover” effect the next day, possibly impairing performance.

Ambien (zolpidem) and Lunesta (zopiclone) can be effective while limiting the hangover effect especially in those who have previosly tolerated the medication (Level A). Zolpidem may be more effective than melatonin and placebo at countering jet lag symptoms. Note: the use of both medicines together was not more effective than zolpidem alone but did cause daytime somnolence.

Stimulants: Care should be used in the athlete as most of these medications are banned in competition. There is a potential off label use for Provigil (modafinil) for improving daytime sleepiness associated with jet lag (currently approved for narcolepsy).

Caffeine, while not banned for the World Anti-Doping Agency, is a monitored substance.  It increases daytime alertness and may accelerate entrainment in new time zones when consumed in the morning (later ingestion may interfere with sleep induction) (Level A).

 

 

References