House Call, MD

by Kelly Erickson, MD 2010 | erickson@myhousecallmd.com

With record-breaking storms keeping many Americans trapped indoors this winter, it is hard to imagine that summer will ever come.  Daydreaming about your spring getaway or summer vacation to Europe may be your only respite from the cold.  But when you consider vacation, especially one that takes you multiple time zones away from home, one of the major drawbacks is coping with the even harsher reality of “jet lag”.  Whether it requires you to sleep when you arrive at your destination rather than enjoying immediate exploration or demands that you take yet another day off from work once you return home, jet lag is undeniably inconvenient.  Here we will explain the causes of jet lag and how to best prevent it from hindering your well-deserved adventures.

What is jet lag?

According to a recently published article in The New England Journal of Medicine, jet lag is a “recognized sleep disorder that results from crossing time zones too rapidly for the circadian clock to keep pace.”  It is a constellation of symptoms that can include insomnia, daytime sleepiness, fatigue, poor physical performance, cognitive impairment and gastrointestinal changes.  What the scientists meant to say was that you are going to feel lousy.   Jet lag is most commonly experienced after crossing at least 5 or 6 time zones (the East Coast-West Coast trip doesn’t apply here!).  Jet lag is most commonly confused with “travel fatigue”, which is the unfortunate result of the combination of sleep deprivation, stress caused by traveling, diet changes, etc.  While travel fatigue can be easily treated with a little rest and T.L.C., jetlag is a horse of a different color.

How does this “jet lag” nonsense happen?

The body’s circadian clock is located in the suprachiasmatic nucleus (SCN) of the hypothalamus (imagine a point directly between your eyes and two inches towards the back of your head…eureka, you’ve found it!).  It communicates with the retina, allowing it to sense light and dark.  Based upon our regularly predictable cycle of waking and sleeping, the SCN promotes alertness or sleepiness in sync with our daily routine by regulating the secretion of melatonin from the pineal gland.  The system works such that light inhibits the secretion of melatonin.  Therefore, melatonin has often been referred to as the “dark hormone”, because it is only secreted when there is no stimulation by external light (aka nighttime).  The problem with this system is that our circadian clock does not adapt quickly to changes in the cycle (i.e. flying half-way around the world in single day).  Therefore, in the same way that “motion sickness” is the result of desynchronization between visual and spatial stimuli in the setting of movement (didn’t know that, did you?), jet lag is the body’s response to the imbalance between a predicted sleep-wake cycle and a change in external light and dark stimuli.

How to Beat It:

1.  Re-sync your clock. This is accomplished with 2 strategies.

• Timing of Light Exposure: Based on what we now know about the circadian clock, we now understand how light can be used as a powerful tool to “trick” the circadian clock and therefore advance or delay it.  Although it may seem logical to think that sleep itself resets the clock, it is actually exposure to light and dark that is most effective.  What does this mean?  Studies have shown that light exposure should be used as follows after travel. Eastward travel: Upon arrival seek exposure to bright light in the morning.  This will help delay your circadian clock.  Westward travel: Seek exposure to bright light in the evening, which will help advance your circadian clock.

• Taking Melatonin:  Because light inhibits melatonin secretion, recommendations for melatonin are the opposite of those for light exposure.  When melatonin is taken in the evening, it resets the body clock to an earlier time and when taken in the morning, it causes the clock to be set to a later time.  Guidelines for melatonin use are, once again, broken down depending upon the direction of travel.  Eastward travel: Take 0.5mg-3mg at bedtime to shift your circadian clock to an earlier time and help you fall asleep.  Westward travel: Take 0.5mg during the second half of the night to shift circadian clock to later time and allow you to continue to sleep.  When traveling westward, the most common sleep disturbance is difficulty staying asleep.  Therefore, melatonin should be taken after awaking in the middle of the night in your new time zone.

2. Plan out your ZZZZZ’s. When planning a trip, you buy your airlines tickets in advance, purchase your travel books and research all of the best sites to visit.  Why not spend a few extra hours sleeping before you leave to help ease the jetlag when you arrive?  More sleep plus less jet lag sounds like a good deal to us.  In general, this means shifting the timing of your sleep 1-2 hours earlier for a few days before eastward travel and 1-2 hours later for a few days before westward travel.

3. Medication. When all else fails, manage your symptoms with some good old-fashion meds.

• Downers (aka sleeping pills):  Studies have shown that 10mg zolpidem at bedtime helps patients get a good night’s rest after long-distance travel and helps to reduce the symptoms of jet lag.  It’s best if you give the medication a test-run before you leave to ensure that you do not have any unwanted side effects while in the safety of your home country (amnesia and confusion…not so fun in a new city where you don’t speak the language).

• Uppers: Caffeine, while generally discouraged for those attempting to overcome jetlag, can be used in small doses early in the day to increase daytime alertness and decrease sleepiness.  Small doses for those of you who missed that part the first time.

The Take Home Message: Jet lag sucks (as the scientists so eloquently explained) but can be mitigated with some planning, preemptive measures before you leave home, and a little proactive management once you’re on the ground in your exotic location of choice (our advice: print out this article so you can remember all these tips when it’s go time).  There’s no reason to feel like poop during your valuable travel time.  Vacation, here we come.  Now get packing!

Questions?  E-mail the author: Kelly Erickson, MD 2010 | erickson@myhousecallmd.com

References:

1.  Sack, Robert L.  Jet Lag.  The New England Journal of Medicine 2010; 362:440-7.

2.  Herxheimer, A., Sanders, M., Mahowald, M., Sokol, H.N., Jet Lag. UpToDate, 2010.

3.  Herxheimer, A, Petrie, KJ. Melatonin for the prevention and treatment of jet lag. Cochrane Database Syst Rev 2002; :CD001520.

4.  Jamieson, AO, Zammit, GK, Rosenberg, RS, et al. Zolpidem reduces the sleep disturbance of jet lag. Sleep Med 2001; 2:423.

5.  Morris HH, 3rd, Estes, ML. Traveler’s amnesia. Transient global amnesia secondary to triazolam. JAMA 1987; 258:945.

There are millions of diets in existence, with new fad approaches to weight loss popping up each month.  From the ever popular South Beach Diet, a high-protein, low-carbohydrate approach, to the very entertaining Cayenne Pepper and Water diet, essentially a starvation diet, it’s hard to sort through the myriad of approaches to weight loss.  Additionally, there is little scientific evidence to support the effectiveness of any of these plans.  Why punish yourself with cayenne pepper water three times a day if it doesn’t even help you lose weight?

This month, the New England Journal of Medicine, one of the most reputable journals in medicine, published the study, “Comparison of Weight-Loss Diets with Different Compositions of Fat, Protein, and Carbohydrates,” to help dieters decode the plethora of diets peppering society.  The study examined 811 overweight adults (people with a Body Mass Index between 25 and 40) who were assigned to 4 different diets.  The participants received regular, personalized diet training during the entire study encouraging diets with less saturated fat, at least 20 g of dietary fiber per day, and low cholesterol.  The four diets studied were classified by the amount of fat, protein, and carbohydrates that each diet consisted of:

1.      Low-Fat, Average Protein: 20% Fat, 15% Protein, 65% Carbohydrates

2.      Low-Fat, High Protein: 20% Fat, 25% Protein, and 55% Carbohydrates

3.      High Fat, Average Protein: 40% Fat, 15% Protein, and 45% Carbohydrates

4.      High-Fat, High Protein: 40% Fat, 25% Protein, and 35% Carbohydrates

The target number of calories consumed per person was calculated as a 750 calorie deficit per day (meaning that if your body consumes 3000 calories per diet, which we call your Basal Metabolic Rate, your target diet would consist of 2250 calories per day).  You’re saying to yourself, “How on earth am I supposed to know what my Basal Metabolic Rate (BMR) is?”  There are a series of formulas that calculate this value for you based on age, height, weight, and amount of exercise you complete each day.  Follow this link to a convenient BMR Calculator (Click on BMR & RMR Calculator…and don’t forget to adjust your caloric need based on your daily physical activity).

After 2 years of monitoring participants weight loss, the study concluded that “reduced-calorie diets result in clinically meaningful weight loss regardless of which macronutrients they emphasize.” Essentially, it doesn’t matter which diet you choose.  The most important factor in creating a diet is calculating the number of calories your body needs to consume, making sure that the diet you design consists of 750 calories less than your BMR per day. The study found that the majority of weight loss occurred in the first 6 months of the diet (i.e. if you haven’t lost any weight after 6 months, you aren’t on the right diet).  Additionally, all of the diets reduced risk factors for cardiovascular disease and diabetes (a definite bonus).

The Take Home Message: The amount of food you consume is just as important, if not more so, than the types of food your diet consists of.  Whichever diet you choose, be sure to calculate your individual caloric needs based on your age, height, weight, and physical activity and are eating the appropriate number of calories per day based on that number.