Travel across time zones is regularly required of profession and collegiate athletes (in addition to the some of us professionally)
Jet lag is defined as insomnia or excessive daytime sleepiness/malaise following travel across at least 2 time zones
Symptoms usually persist 1 day for each time zone crossed
The sleep schedule is primarily modulated by light and melatonin
Secretion of melatonin helps induce sleep
Exposure to light stimulates arousal and inhibits melatonin secretion
Who is at risk?
Those with more rigid sleep habits have more symptoms
“Morning” people have less difficulty flying eastward
“Evening” people have less difficulty flying west
However, overall, eastward travel causes the most severe symptoms which persist for up to 7 days (versus <3 days with westward travel)
(The length of the day gets shortened and the circadian system must shorten to reestablish a normal rhythm. The human body demonstrates a natural tendency toward periods longer than 24 hours)
Those with higher levels of physical fitness adjust more quickly
Effects similar in men and women
Midday arrivals experience fewer symptoms than morning arrivals
Symptoms are less in those who have traveled the journey previously
Symptoms are less in those who had a shorter interval their last full nocturnal sleep in the departure city and their first full nocturnal sleep in the destination city
