Mountains and Caffeine

Effects of Caffeine at High Altitude

Visitors travelling to high altitude destinations have been known to avoid coffee/caffeine intake in order to avoid the dreaded symptoms of acute mountain sickness. The theory is that caffeine leads to dehydration, which then predisposes the individual to acute mountain sickness. A few symptoms of dehydration include headache, lethargy, confusion, weakness and nausea and vomiting. Similarly, symptoms of acute mountain sickness include fatigue, headache, nausea, vomiting, shortness of breath and difficulty sleeping. Although the symptoms of dehydration and acute mountain sickness are very similar, there is no evidence to support this claim that dehydration predisposes an individual to acute mountain sickness.1 Thus, the diuretic effect of coffee and caffeine are often exaggerated. Individuals that are accustomed to drinking 12 oz. of coffee rarely suffer from the diuretic effect of the beverage.1 (See Table 1).

Table 1. Caffeine content (mg) per serving in various foods, drinks and medications.

The condition of acute mountain sickness is a response to hypoxia in the brain’s vascular circulation that causes an increase in the release of a neurotransmitter called adenosine. Adenosine binds to adenosine receptors found on the inner lining of cerebral blood vessels, causing vasodilation of the blood vessels in an attempt to increase the flow of oxygen and nutrient rich blood to the brain. This increase in cerebral blood flow, however, is painful and causes many of the above-mentioned symptoms of acute mountain sickness.

Caffeine, in contrast, counteracts these effects of adenosine in the brain’s circulation by causing vasoconstriction of those cerebral blood vessels, decreasing blood flow within the brain. Therefore, it is likely that caffeine can help prevent the onset of acute mountain sickness because of its ability to decrease cerebral vasodilation in response to hypoxia at high altitude.1 Caffeine is included in several over-the-counter headache medications, such as Excedrin Migraine, exactly for this purpose.

While there is no clinical data exhibiting that caffeine increases the rate at which individuals acclimate to living at high altitude from sea level, physiologic studies suggest that caffeine is helpful in increasing ventilation and decreasing hypoxia. Caffeine stimulates chemoreceptors in the brain and carotid arteries, altering the brainstem’s respiratory center in the medulla oblongata to become more sensitive to low blood oxygen saturation. As a result of this increased sensitivity to hypoxia, the lungs and respiratory muscles unconsciously increase their activity to increase resting ventilation rate and increase blood oxygen saturation.

My Experience

During my six weeks at the Ebert Family Clinic for my pediatric medicine rotation, I measured my blood oxygen levels before and after drinking 12 oz of coffee. My results can be found in Table 2.

Table 2. Six-week average blood oxygen saturation pre- and post-consumption of 12 oz. coffee

Pre-coffee oxygen saturation average: Post-coffee oxygen saturation average:

 

Week 1 91% 94%
Week 2 90% 92%
Week 3 91% 93%
Week 4 92% 94%
Week 5 92% 93%
Week 6 91% 93%

While these results are an anecdotal summary of my own experience living at high altitude and drinking coffee for six-weeks, drinking 12 oz. of coffee showed an average increase of blood oxygenation of 2%.

Caffeine Study at Everest

One study conducted at the base camp of Mt. Everest (17,600 ft) studied the 24-hour effect of caffeine in black tea ingested by one study group compared to a placebo group that only drank water. Both groups ingested the same volumes of liquid in the 24 hours. The study found that both groups had identical urine amounts at the end of the study, suggesting that caffeine did not lead to dehydration. Additionally, the tea-drinking group reported less fatigue and better mood compared to the placebo group.1

Caffeine Withdrawal at High Altitude

Caffeine cessation in fear of dehydration while travelling to high altitude destinations often leads to an exacerbated withdrawal reaction from caffeine, mimicking the symptoms of acute mountain sickness. This is due to the up-regulation, of adenosine receptors in the brain that become uninhibited in the absence of caffeine. As a result, adenosine binds to the increased amount of adenosine receptors in the brain causing excessive cerebral vasodilation and subsequent headache, nausea, vomiting, weakness, lethargy and confusion. Therefore, regular coffee drinkers or any type of caffeine users should avoid abrupt cessation of caffeine intake while traveling from sea level to high altitude.1

Future Studies

The above mentioned studies have not studied the effects of caffeine in caffeine-tolerant vs. caffeine-naïve individuals, but a trial of caffeine in the form of either coffee, tea or pill would be worthwhile in otherwise healthy individuals suffering from symptoms of acute mountain sickness while visiting high altitude locations. Future studies would benefit from comparing the effects of caffeine on caffeine tolerant individuals and individuals who do not consume caffeine on a regular basis. However, individuals must always consult their health care provider to determine if it is safe to use caffeine prior to consumption of caffeine products.

Michael Peterson, PA-S

University of St. Francis, Physician Assistant Program

It’s so exciting to be CITED!

Today I opened the March 2018 issue of the Journal of High Altitude Medicine and Biology.

What a surprise!

My publication  was cited in an article on pulmonary edema in children written by professors in the pulmonary department at Children’s Hospital of Colorado!  This is actually the first indication I’ve had that anyone beside me believes in the entity I called Mountain resident HAPE in the article published in the same journal last September.

Dr. Liptzin and her colleagues wrote, “We briefly describe high-altitude illnesses and propose recommendations for evaluation and treatment of HAPE in children as well as investigate the underlying contributors to HAPE. We discuss high-altitude resident pulmonary edema (HARPE), a new entity (Ebert-Santos, 2017). We will also highlight areas for further research.” The authors do not recommend prophylactic treatment for HAPE. Rather they recommend that when symptoms develop, supplemental oxygen be applied and  descent to lower altitude.

Summit v.s. Saipan: Running

Dr. Chris and Jacqueline, her niece from Guam, enjoy the Beach Road rec path in Saipan

When I lived on Saipan in the Pacific and visited my parents in Breckenridge I noted that my 10k  times were just as good at 9000 ft with humidity around 27% and temperatures in the 70’s as at sea level with 80% humidity and temperatures in the 80’s. Last month I had the same experience, in reverse: living at high altitude and visiting Saipan. Reading our blog on asthma, I attribute that to the lower viscosity of air and lower air pressure in the mountains compared to the high density of water vapor in the islands.  Both locations are beautiful and inspiring places to run!

Pediatrics Gun Storage Practices

The American Academy of Pediatrics published a new study titled “Firearm Storage in Homes with Children with Self-Harm Risk Factors.” The conclusion of this article was that parent’s decision to have firearms in the home as well as their storage practices were not influenced by the presence of a child with a mental health condition in the home. The study was comprised of a web-based survey, which was completed by parents of 3,949 households in the US. The results showed that approximately 42% of households that contained children confirmed having a firearm in the house. This percentage did not change when comparing household in which children with mental health reside to those whose children had no mental health issues. The study also showed that of those parents/ caregivers who own firearms only 1 in 3 stored all firearms locked and unloaded. This ratio did differ between households that contained children with mental health issues versus those that did not.

This study led me to question the role of pediatrics in determining the ownership and storage of firearms in homes with children. At every well child visit for children above a certain age we ask if there are any firearms in the house and if so, how are they stored. I found myself wondering “Have studies shown a decrease in injury by firearms following pediatrician intervention and education?” A study published in 2000 concluded that “a single firearm safety counseling session during well child care combined with economic incentives to purchase safe storage devices, did not lead to changes in household gun ownership and did not lead to statistically significant overall changes in storage patterns.” However a randomized controlled trial published more recently, in 2008, concluded that a brief office-based violence prevention approach resulted in increased safe firearm storage.

The American Academy of Pediatrics first issued guidelines in 1992 noting that the safest home for a child is one without firearms. These guidelines also note that if firearms are going to be in households they should be locked and unloaded with ammunition stored separately. I grew up in a house of avid hunters and gun owners and I can just hear them saying, “What good is a gun in the case of an intruder if it is not immediately accessible?” One study in the Journal of Trauma found that “guns kept in homes are more likely to be involved in a fatal or nonfatal accidental shooting, criminal assault, or suicide attempt than to be used to injure or kill in self-defense.” This article claims that the benefit of having a gun in the house for self-defense does not outweigh the risk of accidental injury by that same “protective” weapon. Other’s who advocate for firearm use and ownership claim that if children are properly educated and trained in gun safety there would be less accidental shootings. However, one study published in 2002 had children participate in a weeklong firearm safety program on reducing children’s play with firearms. Following this training period the children were exposed to an unloaded firearm. 53% of the children played with the gun as if it was a toy gun. This study cast doubt on the effectiveness of skills-based gun safety programs for children.

I recognize that it would be naïve of me to think that every gun owner with children in the house is going to forfeit his or her right to their firearms because of this data. That is why there are important organizations such as Project Childsafe (http://www.projectchildsafe.org/parents-and-gun-owners) that cater towards gun owners. This organization provides comprehensive information about gun safety in the home and offers free resources such as cable-style gunlocks to further protect children in their homes.

Jocelyn Rathbone PA-S

References:
Scott J, Azrael D, Miller M. Firearm Storage in Homes With Children With Self-Harm Risk Factors. Pediatrics 2018 March; 141(3): e20172600. Retrieved March 11, 2018.
Kellermann AL, Somes G, Rivara FP, Lee RK, Banton JG. Injuries and deaths due to firearms in the home. J Trauma. 1998 Aug; 45(2):263-267. Retrieved March 11, 2018.
Barkin SL, Finch SA, Ip EH, Scheindlin B, Craig JA, Steffes J, Weiley V, Slora E, Altman D, Wasserman RC. Is office-based counseling about media use, timeouts, and firearm storage effective? Results from a cluster-randomized, controlled trial. Pediatrics. 2008; 122(1): e15. Retrieved March 11, 2018.
Grossman DC, Cummings P, Koepsell TD, Marshall J, D’Ambrosio L, Thompson RS, Mack C. Firearm safety counseling in primary care pediatrics: a randomized,  controlled trial. Pediatrics. 2000; 106(1 Pt1): 22. Retrieved March 11, 2018.
Hardy MS. Teaching firearm safety to children: a failure of a program. J Dev Behav Pediatr. 2002;23(2):71. Retrieved March 11, 2018.
Gill AC, Wesson DE. Firearm Injuries in Children: Prevention. UptoDate. Literature review current through Feb 2018. Last updated March 14, 2018. Retrieved March 11, 2018.