Tuesday, August 27, 2013

What can they be thinking?

The following item caught my attention recently:

 http://www.huffingtonpost.co.uk/2013/08/06/sunburn-pain-relief_n_3711613.html

The actual scientific study on which the above article was based is published in a very highly respected journal, Proceedings of the National Academy of Sciences:

http://www.pnas.org/content/110/34/E3225.long 

The actual science here is impeccable.  The research reports that a molecule, TRPV4, is involved in producing the pain of sunburn, and that a newly designed compound targeting this molecule inhibited the pain and blistering of sunburn in a mouse model.  The implication is that such a compound could eventually be used to attenuate the burning and blistering of sunburn in humans.

Well, maybe.

The development of sunburn pain, like any pain, is a very complex cascade; this study shows that TRPV4 is an important part of that cascade.  This is exciting new information, which has implications beyond sunburn.  However, there are other well-known components of this cascade, including something called the "prostaglandin pathway." We already know how to inhibit prostaglandin-mediated pain and inflammation: the use of "non steroidal antiinflammatory drugs" (NSAIDS), of which ibuprofen is perhaps best known.  It has been known for a long time that taking ibuprofen or similar agents right after excessive sun exposure markedly reduces pain and blistering. 

The issue is that the pain and blistering of sunburn is really only a small part of the problem.  The UV light which produces the sunburn also damages DNA in cells of the skin.  This damage can ultimately lead to the development of skin cancers such as melanoma.  As I have pointed out in other writings, melanoma caused by sunburn is the most common cause of death in outdoor recreation.  Ibuprofen, or some expensive new TRPV4 antagonist, may well minimize the acute pain of sunburn.  It would do nothing to prevent skin cancer.  Sunburn is our body's way of saying "You jerk!  Don't you know that you are setting yourself up for cancer?"  Why would we want to do anything to take away from this important message?

 

Wednesday, June 19, 2013

Updates and shameless promotion

Despite best of intentions for more regular posts, it's been a pretty dry few months!

Several recent Adirondoc columns are now available through the publications link.

Some time ago, I mentioned Erik Schlimmer's development of a route across the Adirondacks, from Blue Line to Blue Line, which he dubbed the "Trans Adirondack Route."  Erik has now produced a guidebook and video for the route, both of which I highly recommend:  http://www.transadk.com/

I was recently interviewed for a program ("Health Link") discussing the health benefits of wilderness travel.  The link to the interview is: http://blogs.upstate.edu/healthlinkonair/2013/03/28/how-to-prepare-for-hiking-and-mountain-climbing/

Monday, December 31, 2012

Happy New Year!

Looking back over my posts for this year, I realize that I haven't been a very prolific blogger.  Frankly, I can't understand how some folks have the time to keep their blogs so current!  I have, however, continued to keep up my regular column for Adirondac magazine, most of which reads like a blog anyway.  Check out the publication link for some of these.

With winter coming on, the Caribbean cruise industry is in full swing.  I suspect that most readers of this blog don't spend too much time on vessels like the Queen Mary II, but there is actually a very nice wilderness medicine connection.

December was a bad month for cruise ships.  In addition to rather flagrant violation of basic Leave No Trace principles (http://www.foe.org/cruise-report-card), there have been a number of very high profile outbreaks of intestinal infection on some luxury liners:

http://news.sky.com/story/1031527/norovirus-cruise-outbreaks-on-two-ships

How would you like to spend 10 grand or more for a cruise, and wind up puking on the floor of your cabin with the staff forbidden to enter your room?  These are hardly isolated incidents; the Centers for Disease Control and Prevention has a nice summary of reports over the decade:

http://www.cdc.gov/nceh/vsp/surv/gilist.htm

Most of these outbreaks in which the cause could be established were related to Norovirus, a well-described cause of epidemic gastroenteritis.  In addition, however, virtually every other infectious cause of gastroenteritis (including giardiasis) appears on this list.

Where's the backcountry connection?  Believe it or not, there are actually some biologic similarities between cruise ships and backcountry treks.  Both situations take a group of individuals from different backgrounds and locales and put them together for a prolonged period sharing close spaces, eating together, and sharing toileting facilities. 

Epidemiologists have long recognized that such environments are a prime condition for the hand-to-mouth spread of intestinal infections.  Poor hygiene on the part of cruisers leads to surfaces on the ship becoming contaminated, spreading infection.  While this certainly can happen in other public venues such as restaurants and hotels, these do not keep the same group of people in the same environment for several days at a time. Cruise ships do not spend a lot of time worrying about their drinking water; instead, they are compulsive about cleaning surfaces and encouraging their clients to pay attention to personal hygiene.  When outbreaks do occur, the CDC invariably implicates hand-to-mouth spread.

Except in developing countries with no sanitation infrastructure, water is not a very efficient means of spreading intestinal infections.  As the cruise ship experience demonstrates, however, breakdown in personal sanitation is the major way in which such infections spread. 

So, whether your winter travels will be in the Caribbean on a cruise or in the Wind River Range on a trek, enjoy and stay healthy.  In either place, be sure to wash your hands!

Tuesday, August 7, 2012

"Sports Drinks" and the backcountry

The estimable British Medical Journal has just published a provocative expose on the "sports drink" industry.  You know the stuff:  Powerade, Gatorade, etc.  As you're watching the Olympics, no doubt you've caught some screen shots of competitors drinking them and have seen their ads.

The theory behind these products is deceptively simple:  Dehydration leads to decreased athletic performance.  Salts are lost along with water during exercise.  Exercise requires caloric expenditure.  Voila!  Along come products with a perfect balance of water, salt, and carbohydrate.  The products come with an impressive resume of "clinical trials" attesting to their benefit, and are endorsed by a number of athletic organizations.

At first, I wasn't sure that this expose would be of interest to the wilderness traveller.  As a little experiment, however, I checked out "sports drinks" and "electrolyte drinks" on a few of my favorite on-line retailers of backpacking gear:  Campmor, EMS, and REI.  All offer a wide variety of powdered and tablet forms of these for the camper.  EMS, for example, features "GU Electrolyte Brew".  The EMS website claims that the product will "get your system back in balance" and "help you go longer".  Hum...

I urge you to read this report yourself.  It is in the July 18, 2012 issue of the BMJ, which should be available in many university libraries.  Online access is available at:

http://www.bmj.com/content/345/bmj.e4737.pdf%2Bhtml

The quick summary of the report is not pretty.  The real science behind these drinks is almost completely lacking.  Company claims to the contrary, when the medical journal attempted to review these studies it found virtually none of sufficient methodologic rigor to withstand scrutiny.  The few which had been published in journals were overwhelmingly published in very low-impact journals with clear ties to the sports drink industry.  For example, the journal Medicine and Science in Sports and Exercise is published by an organization with long-standing financial relationships to Gatorade, and has a number of "Gatorade affiliated scientists" on its editorial board.

The promoters of these products have largely "invented" dehydration as a common problem in endurance exercise, and have encouraged the promulgation of completely unsubstantiated recommendations for overhydration during sports.  Unfortunately, these are filtering down to youth sports.

Is there a problem with all this?  There is.

First of all, sports drinks contain calories--hundreds per serving.  This may not be a problem for truly active folks, but the average person drinking Gatorade isn't Usein Bolt!  By marketing an image of health and vigorous exercise, companies fool the average (mostly sedentary) user into thinking that he is drinking something other than, essentially, sugar water with a dash of salt.

More importantly, however, the widespread emphasis on sports hydration over the past few years is likely fueling a real problem:  hyponatremia.  This condition, which is basically a fancy name for water intoxication, is a serious cause of death and disability in some endurance sports.  There are at least 16 recorded deaths and over a thousand critical illnesses in marathon running alone attributable to hyponatremia.  Although sports drink makers insist that the salt content of their beverages avoids this complication, this is not correct.  Indeed, an actual scientific study of marathon runners has shown that the volume of liquid consumed, independent of its composition, is the major factor in causing hyponatremia. 

Millions of years of evolution have led to our bodies having an excellent mechanism for preventing dehydration.  The mechanism is "thirst".  Pay attention to it.  When it calls, have a drink.  Of water.  Right from the stream!

Wednesday, May 23, 2012

Just when I thought I'd heard everything....

The things folks do in the backcountry never cease to amaze me.  Check out this recent item from the Albany Times Union regarding some guys who became lost recently in the Adirondacks:

http://m.timesunion.com/tu/db_109215/contentdetail.htm?contentguid=QCPcA8PG&full=true#display

Peeing on each other to stay warm?  Yikees!

Of course, equally important to keeping warm is keeping dry.  This was obviously a counterproductive strategy.  Since their names were used in the article, I suspect that most of their friends have come across this news item.  At least they survived.

This brings to mind an occasional question about hypothermia--is it better to hold onto urine because it is warm, or empty your bladder? (Urinating on another camper is not usually one of the choices.)  The correct answer is that it makes no meaningful difference.  Urine is only warm because the body keeps it heated, so in theory less heat would expended if there were less urine in the bladder to heat.  In the big scheme of things, however, the impact of this on total heat balance would be trivial. More importantly, most people with serious hypothermia are somewhat dehydrated, so the most important thing is to be drinking enough that it isn't possible to hold it! 

Just don't pee on your friends.

Monday, April 9, 2012

The "Trans Adirondack" Route

Erik Schlimmer is a good friend with whom I have guided in Alaska previously. He is one of the few people who approach me in the volume of untreated Adirondack water he has consumed without ill effects!

Erik has a number of "firsts" under his wilderness belt, most of which I would have no desire to duplicate. (Canoeing the lower Hudson? Yuck!) His most recent, however, looks like a lot of fun. He has outlined a 235 mile route which traverses the Adirondack Park. He will be releasing a guidebook early next year (Blue Line to Blue Line) which details the route.

This summer, Erik is working with one of his former students to produce a documentary which will coincide with the launch of his book. Information on the route and the planned documentary is available at:

http://www.kickstarter.com/projects/1559964226/trans-adirondack-route-documentary

Saturday, March 17, 2012

Survival Lesson

For many of our frontcountry friends, outdoor education somehow equates with survival training. Such staples of television as "Man vs Wild" and "Survivorman" certainly add to this view. I had a personal taste of this a while ago when interviewed for a newspaper profile (http://adirondoc.com/publications/profile_post_061209.pdf). Not being a fan of the Discovery Channel (We only pay for basic cable.), I had a difficult time believing the reporter's questions about the utility of eating bugs and drinking urine as a survival skill. Apparently, such tripe is regular fare on such programs.

I was thinking about this the other day while reading about the seemingly amazing story of a 41 year old woman surviving a 3 1/2 week "ordeal" in the mountains of New Mexico (http://www.columbiatribune.com/news/2012/mar/10/missing-woman-survives-weeks-lost-in-nm-forest/).

No food--no water purification devices--no map or compass--below-freezing nights--her destination unknown to friends or family: this seemed like an obvious set up for fatality.

How did she survive?

Although the data are sketchy, it seems that she pretty much ignored common teaching about survival in such situations.

First of all, she drank plenty of water from a nearby creek, without fretting about its quality. While this might seem pretty basic, compare it to the arguably better-prepared chap I discussed in an earlier posting (April 27, 2010), who nearly died after a shorter period being lost because he avoided drinking for fear of water-borne illness.

Then, there is the matter of food. We often hear that the body cannot survive longer than ten days without food. This has led to the nonsense of courses on "edible plants", trapping small animals, eating bugs, etc. No one seems to realize that the energy expended by such efforts likely exceeds the minimal caloric content of the "food". Actually, the body's tolerance of extended fasting is well documented--time in excess of 40 days has been shown for centuries. Indeed, mammalian physiology is well adapted for extended periods without eating. (This is the reason that calorie restriction alone is rarely sufficient for extended weight loss.) The woman in question wasted no time or energy in pursuit of food.

She also stayed put. Although conventional teaching might have called for her to follow the nearby creek downstream, she chose not to do so. (Apparently, the unfortunate woman had some emotional disorder which contributed to her predicament, so this may not have been an informed "choice".) Rather than wasting energy and risking injury by walking distances, she simply stayed put, stayed warm, stayed dry, and waited. There are not too many areas in the US where a lost person cannot ultimately be found if she waits long enough--especially after abandoning a car.

Sure, she made some mistakes (albeit possibly intentional) which led to her near-miss. Nonetheless, we should remember the lesson of Margaret Page before pontificating on wilderness survival to our students.