CONSEQUENCES OF JET LAG

Sleep deprivation is the first adverse consequence associated with jet lag. Most of us require seven to eight hours of sleep per day to maintain optimal functioning. We can “get by” on much less sleep, but if we get less than our optimal amount, we become sleep deprived; unfortunately, this deprivation accumulates, and we can’t fully recover until we sleep it off. Sleep deprivation hurts us in many ways—increasing reaction time; decreasing memory, concentration, and alertness; slowing cognitive functions; and causing general fatigue and excessive daytime sleepiness. Just 24 hours of sleep deprivation will decrease glucose metabolism in certain areas of the brain. Accidents and injuries are often linked to sleep deprivation.

The disruption of our circadian rhythms is the other major consequence of jet lag. Circadian rhythms, the patterns of biological fluctuations that occur

Roger S. Smith LEVELING THE BOSTON COURSE SPECIAL BOSTON

with a rhythmic period of approximately one day, are orchestrated by the biological clock. An obvious manifestation of these circadian rhythms is the sleep/ wake cycle discussed earlier. This is why you fall asleep and wake up at roughly the same time each day. ~

Many other physiological processes follow a rhythm of oscillation from peak to nadir throughout a 24-hour period. Human performance is adversely affected when the timing of these biological processes is disrupted. It is no great leap to conclude, then, that sleep deprivation and circadian rhythm disruption impair athletic performance.

Specific studies of jet lag and athletes are limited in number, and the results are sometimes condtradictory. Let’s consider the two sides.

WHAT THE STUDIES SAY

The adverse effects of jet lag on athletes include reduction in anaerobic power and capacity as well as reduced dynamic strength. Jet lag has also been associated with disrupting subjective mood states, decreasing vigor, and increasing fatigue and confusion.

Elite gymnasts who took transmeridian flights (across time zones) in both westward and eastward directions experienced some minor disturbances in blood pressure and heart rate rhythms, which persisted up to 11 days after their arrival. After transmeridian flights, pilots have also demonstrated impaired psychomotor and cognitive performance. After crossing six time zones, soldiers ran slower times in a 270-meter sprint and a 2.8K run. One study that examined 1,081 professional baseball games showed that the home team’s winning percentage increases significantly when its opponent travelled across the country. The authors of the study concluded that this effect was due to jet lag. In arecent study on Korean Olympic athletes, preliminary results indicate that athletes needed an average of 4.2 days to return to subjective baseline athletic performance after travelling from Korea to Atlanta. After their trip to Atlanta, 90 percent of the Korean athletes experienced fatigue, and 40 percent experienced decreased strength. As stated before, general research has revealed that people are affected differently by jet lag. This was reflected in the research on the Korean Olympic athletes: Only one-half of the group studied demonstrated a subjective increase in daytime sleepiness after crossing 10 time zones. Contrary to the above results, one study of 18 college swimmers did not show any negative physiological consequences with travel across four time zones.

SPECIAL BOSTON SECTION

HOW TO COUNTER JET LAG

We could fill several books with the inaccurate information disseminated about overcoming jet lag. Suggested treatments have included everything from insignificant dietary recommendations to potentially harmful advice that could worsen the symptoms. The most helpful suggestions are those based on circadian rhythm physiology.

Adjust Your Clock Before You Leave

The simplest way to help counter jet lag is to begin adjusting your circadian clock before the trip begins. For example, if you travel to the Boston Marathon from the West Coast, you will be out of phase by three hours. This means that in Boston, your biological clock will be telling you to fall asleep and wake up three hours later than your usual bedtime and rising time. To avoid this disruption of sleep, begin to adjust your circadian clock a few days before leaving for Boston.

Go to bed one hour earlier each day for two or three days before leaving. This will essentially place your biological clock on eastern standard time upon your arrival in Boston. This strategy essentially eliminates this degree of jet lag. It is very important that you shift the wake-up time in the same direction, and to the same degree, as the bedtime. It is also wise to shift other activities (like eating) along with the sleep/wake cycle. If you are travelling to Boston from Hawaii (a five-hour shift), you should start shifting your ciradian rhythms like the West Coast athletes, but plan to finish shifting them during the first two days in Boston, prior to the race.

Use Light and Dark to Your Advantage

The most powerful tool for adjusting the biological clock is bright light. There is adirect connection from the eye to the cells that make up the biological clock in the brain. Bright light tells the clock to wake up the body; likewise, darkness sends a message that it’s time to sleep. You can take advantage of this information and expedite the circadian adjustment by exposing yourself to light when you want to be awake and darkness when you want to sleep. A word of caution: Never attempt to instigate the waking effect by looking directly into a bright light. Doing so can damage your eyes.

Stay in Your Time Zone

Another strategy for dealing with the jet lag that accompanies a west to east flight is simply to remain on West Coast time for the duration of the trip. This may work well if you have to arrive in Boston the night before the race and are

Roger S. Smith LEVELING THE BOSTON COURSE ® 39

A Word of Caution about Melatonin :

M ELATONIN is a hormone secreted by the pituitary gland in response to a dark environment. Itdoes have some sleep-inducing effects on humans and has shown promise in treating jet lag. Melatoninis available to the publicin health food stores, but it may not be harmless. Because melatonin is not regulated by the FDA, it has not undergone the same rigorous testing that

Melatonin‘s unregulated status means that you cannot be sure what you’re getting when you purchase it. The dose recommended on the label may produce greater than normal levels of melatonin in your body. Research is underway, and some studies have been completed in Europe; but until appropriate scientific studies show that melatonin is safe and effective for combating

other medications receive to determine the risk/benefit ratio.

jet lag, using it is unwise.—RS

Haven’t the faintest idea what anyone is doing in this scene, so I’ ll use the light and dark approach and get some sleep by staying in the West Coast time zone. But there are a few drawbacks with using this strategy for more than roughly a day. It is difficult to maintain the West Coast time when you are in the eastern time zone. The internal clock will do its best to make a readjustment on your behalf. It will receive cues from the sunlight and from social activities such as eating. Another potential problem with this strategy is that many athletes perform better in the afternoon than in the early morning. Since the Boston Marathon begins at noon EST, an athlete attempting to remain on West Coast time would be starting the race at 9 A.M. relative to the biological clock. This may not be the most opportune circadian time to run the race.

OTHER PROBLEMS ASSOCIATED WITH TRAVEL

Even if you don’t suffer from jet lag, other symptoms frequently associated with long-distance travel may bother you—dehydration, physical inactivity, noise, hunger, and stress. The degree to which these affect athletic performance is unknown, but the general consensus is that they are all unpleasant and unnecessary. Anticipating and addressing these potential problems may make your trip more enjoyable. When you’re on the road, you can help keep your circadian rhythms in sync by staying well hydrated, eating regular meals at regular times, and exercising at regular times. Also consider using foam ear plugs in noisy environments so you can sleep well, …and dream of the “best race of your life.”

Roger S. Smith LEVELING THE BOSTON COURSE ® 37