| What is Jet Lag?
The timing of the sleep/wake cycle, and many other biologic processes, is regulated by a biologic clock located in the brain. When we rapidly cross time zones in airplanes, the biologic clock cannot readjust quickly enough. As the body clock scrambles to catch-up, the timing of our biologic processes becomes disrupted and we feel the symptoms identified as jet lag. These include:
- fatigue
- excessive sleepiness
- disorientation
- light-headedness
- loss of appetite
- gastrointestinal disturbance
- insomnia
- difficulty concentrating
The severity of jet lag is dependent upon several things: the number of time zones crossed, the direction traveled (east or west), and individual susceptibility (some people are more severely affected than others). For example, you may not notice any symptoms after crossing one or two times zones, but you will certainly have some jet lag after crossing 12 time zones.
Jet lag does not occur if you stay within the same time zone because you do not need to readjust your biologic clock. However, other unpleasant consequences of travel can still occur such as dehydration, stress, and muscle soreness/stiffness.
What are the Effects of Jet Lag on Athletic Performance?
Jet lag often causes sleep deprivation and circadian rhythm (body clock) disruption. These, in turn, may lead to adverse consequences that may affect athletic ability such as:
- prolonged reaction time
- decreased short term memory
- decreased concentration
- reductions in anaerobic power and capacity
- increased accident and injury rate
- reduced dynamic strength
- decreased alertness
- cognitive slowing
The degree of these consequences ranges from imperceptible to very significant. With such a narrow margin of victory in today's competitive sports, it makes sense for athletes, coaches, and athletic trainers to consider jet lags potential effects on performance.
How is Jet Lag Treated?
A rule of thumb states that it takes one day for the body clock to adjust to each time zone you cross. Complete readjustment to a trip from the United States to Europe often takes 6-10 days. Luckily, we can shorten this adjustment process through our understanding of the body clocks physiology.
In general, jet lag is treated by gradually shifting the sleep/wake cycle (bedtime and wake-up time) by exposure to bright light at certain times of the day. The details of this treatment are determined by the direction of travel (east or west) and the number of time zones crossed. The general jet lag guidelines presented below have been simplified for ease-of-use.
How about Melatonin?
Melatonin is a neurohormone that is not regulated/tested by the FDA. The risk of taking melatonin has not been clearly established yet. Some studies suggest that it helps with jet lag, but until more studies can demonstrate its safety profile you should probably avoid melatonin.
General Travel Tips
Some unpleasant feeling are blamed on jet lag, but are really due to other things. Dehydration, physical inactivity, noise, hunger and stress frequently occur with long distance travel and often cause the traveler to feel poorly. Anticipating and addressing these problems may make your trip more enjoyable and successful. Let's look at how you can avoid these problems:
- DEHYDRATION - Many people do not consume enough fluids when they are traveling and they become mildly dehydrated. Dehydration can make people feel light headed, dizzy, sick to their stomach, and can cause headaches and constipation, etc. To avoid this situation, drink adequate amounts of non-caffeinated, alcohol-free beverages such as fruit juice, fluid replacement drinks and water.
- INACTIVITY - A lack of physical movement or activity frequently accompanies air travel. This decreased activity can produce muscle and joint stiffness, backaches, etc. Regular physical activity counteracts these problems and even helps our immune systems function properly. Try to get up and stretch or walk at least every 2 hours.
- STRESS - Traveling is often stressful, and stress can cause all kinds of trouble! Muscle tension, irritability, anxiety, headaches, stomachaches, insomnia, etc., can be signs of stress. There are many books and professionals available to advise you on the topic of stress reduction and coping skills. In general, after you recognize the signs of stress, reduce the stress with something that you find relaxing.
- NOISE - Noise can disturb your sleep (without you even knowing about it) and noise can increase your stress level. One of the best travel investments known to humankind is a set of foam ear plugs. The foam ear plugs you can get from your local hardware store cost about a dollar, and can be used many times. They are easy to sleep with.
- DIET - Finding food of sufficient quality and quantity when you are traveling can be difficult. Try to carry some of your favorite portable foods with you. Some versions of an energy bar is a decent choice as it travels well and gives you a variety of nutrients.
- NAPPING - Brief naps (no longer than about 15-20 minutes) can decrease sleepiness, improve performance, and induce a sense of well being ("that nap felt good"). Longer naps, on the other hand, can confuse the body clock and can produce the opposite effect.
Be any sure to test major changes in your travel strategy prior to implementing them on your next important trip!
Light Exposure
Light exposure is arguably the most powerful tool we have for readjusting the body clock. There is a direct neurologic connection from the eye to the body clock which allows light to adjust the clock every day. We can use this physiological knowledge to readjust the clock more quickly.
Simply being outside (even on a cloudy day), or in a brightly lit room is usually enough light exposure. This may sound obvious, but it is also important; it should be light when you want to be awake, and dark when you want to sleep.
Travel Guidelines
Find the time zone change and direction of travel that best fits your trip and follow the guidelines.
0-2 Time Zones, East or West
Jet lag is rarely problematic with these trips, therefore no specific recommendations are provided.
3-5 Time Zones, West
Jet lag is often present with these trips.
Prior to leaving, gradually shift your BT and WT 1-2 hours later than usual. A couple of days before you leave, get light exposure for at least 30 minutes sometime in the 2 hours before you go to bed.
Upon arrival, start with a BT and WT 1-2 hours earlier than usual and gradually shift towards your usual BT and WT. Get light exposure for at least 30 minutes sometime in the 2 hours before you go to bed for the first couple of days.
3-5 Time Zones, East
Jet lag is often present in these trips.
Prior to leaving, gradually shift your BT and WT 1-2 hours earlier than usual. A couple of days before you leave, get light exposure for about 30 minutes and when you first get up in the morning.
Upon arrival, start with a BT and WT 1-2 hours later than usual and gradually shift towards your usual BT and WT. Get light exposure for about 30 minutes when you first get up in the morning for the first couple of days.
6-8 Time Zones, West
Jet lag is almost always present with these trips and is of moderate intensity.
Prior to leaving, gradually shift your BT and WT 2-3 hours later than usual. For a few days before you leave, get light exposure for at least 30 minutes sometime in the 2 hours before you go to bed.
Upon arrival, start with a BT and WT 2-3 hours earlier than usual and gradually shift towards your usual BT and WT. Get light exposure for at least 30 minutes sometime in the 2 hours before you go to bed for the first few days.
6-8 Time Zones, East
Jet lag is of moderate to severe intensity.
Prior to leaving, gradually shift your BT and WT 2-3 hours earlier than usual. For a few days before you leave, get light exposure for about 30 minutes when you first get up in the morning.
Upon arrival, start with a BT and WT 2-3 hours later than usual and gradually shift toward your usual BT and WT. Try to get light exposure for about 30 minutes when you first get up in the morning for the first few days.
9-12 Times Zones, West
Jet lag is of moderate to severe intensity.
Prior to leaving, gradually shift your BT and WT at least 3 hours later than usual. For at least a few days before you leave, get light exposure for at least 30 minutes sometime in the 2 hours before you go to bed.
Upon arrival, start with a BT and WT at least 3 hours earlier than usual and gradually shift towards your usual BT and WT. Get light exposure for at least 30 minutes sometime in the 2 hours before you go to bed for at least the first few days.
9-12 Time Zones, East
Jet lag is of moderate to severe intensity.
Prior to leaving, gradually shift your BT and WT at least 3 hours later than usual. For a least a few days before you leave, get light exposure for at least 30 minutes sometime in the 2 hours before you go to bed.
Upon arrival, start with a BT and WT at least 3 hours earlier than usual and gradually shift toward your usual BT and WT. Get light exposure, for at least 30 minutes sometime in the 2 hours before you go to bed for at least the first few days.
Final Notes
- Do not expect to be performing, coaching, etc. at your best for the first 1-2 days after these trips. Give your body a chance to acclimatize to the new time zone.
- You may notice that the 9-12 Time Zone East and the 9-12 Time Zone West guidelines are the same. This is because the body clock will essentially shift in the same direction for either trip.
- All guidelines are relative to local time. Adjust your watch to the new time zone on the airplane.
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