Source for cover photo: Pixabay

Hiking has become an increasingly popular activity across the world. In the United States alone, over 47 million people went hiking in 2018. In Switzerland, hiking is almost a national pastime – 44% of Switzerland’s citizens identify themselves as hikers. The Covid-19 pandemic is driving droves of new hikers outdoors.

Like other outdoor activities, hiking carries the risk of injury or death from natural or accidental events. Researchers from the Institute of Forensic Medicine at the University of Bern, Switzerland, recently analyzed medical reports of hiking deaths in the Berne region from 2003 to 2018. By identifying common elements between deaths, the researchers aimed to recognize troubling trends and give recommendations to prevent future hiking deaths.

Researchers identified 77 fatal hiking accidents that occurred in the area during the fifteen year period. For each reported death, the researchers selected 25 different factors that may have affected the rate of hiking deaths across various altitudes. These included person-determined factors, such as pre-existing conditions, hiking experience, and equipment, as well as environmental factors such as the time the accident occurred, weather patterns, and the location of the hiking trails where the accidents took place. Around half of the deaths occurred under the treeline in the region, around 1800 meters, and half occurred above the treeline. The scientists focused on the causes of death and circumstances based on the altitude, which allowed certain problematic trends to emerge.

Both inexperienced hikers and hikers who experienced accidents below the treeline were significantly more likely to lack proper equipment, such as hiking boots and appropriate clothing, than experienced hikers and those hiking at higher altitudes. Researchers also found that foreign hikers visiting were more likely to lack the proper equipment than local hikers. An EU report discovered that “mountains and water” pose particular risks to foreign tourists, as these conditions change rapidly and are unfamiliar to tourists. Hikers with little experience were more than twice as likely to have equipment shortages than experienced hikers. Underestimating and underpreparing for the trail can have disastrous consequences.  

When researchers looked at differences in the cause of death for the cases, they found that traumatic brain injuries (TBIs) occurred significantly more frequently in the high-altitude deaths. The average height of a fatal fall was over 40m higher in the high-altitude group. High-altitude hikes were more likely to take place on rocky trails, which could have contributed to the higher number of traumatic impacts causing TBIs.

Another factor in high-altitude hiking is the maximum volume of oxygen (VO2 max) one can breathe in. Higher altitudes have decreasing concentrations of oxygen in the atmosphere, so every breath brings in less oxygen for the body. VO2 max deceases roughly 10% with every 1000m gain in elevation. While adjusting to high altitude, hikers can experience shortness of breath and headaches due to the decreased oxygen; these physical limitations inhibit the performance of even experienced hikers. These limitations, combined with rocky or slick trails, can increase the likelihood of accidental falls.

Finally, one of the largest factors affecting mortality in these hiking accidents was the hiking surface. Over a third of the accidents occurred when a hiker veered off-trail, whether intentionally or accidentally.  Researchers found that one possible reason for the large proportion of hikers travelling off-trail was hikers underestimating the danger of their surroundings. This, combined with hikers misjudging which types of shoes and equipment would be beneficial in the backcountry, led to an increased risk on otherwise safe and well-travelled trails.

The application of forensic medicine to medicolegal death investigations creates insight into the circumstances surrounding investigated deaths and suggestions for preventative strategies. Zürcher, Jackowski, and Schön strongly suggested that local governments increase their accident prevention information for young and inexperienced hikers, as well as foreign visitors. Increased awareness of the common hazards in the environment will lead to fewer accidents, fatal or minor, and increase our hikers’ safety.

Author’s Note: While spending two summers as an employee in two U.S. national parks (the Old Faithful area of Yellowstone and the Lake McDonald area of Glacier), I observed many of the hazards identified in this article. It was not uncommon for hikers to underestimate hiking trails and take off without proper footwear or enough water for the trek. Visitors were often unaware of the elevation change; at 7700 feet above sea level, many people who visited Yellowstone suffered headaches, dehydration, and nosebleeds as they acclimated to the altitude. These problems were exacerbated by strenuous physical activity and required several visitors to be airlifted from the park to nearby hospitals.

The national parks offer numerous outdoor activities for people of all ages and abilities. Researching the environmental conditions and planning accordingly is the best preparation for outdoor trips and can help hikers avoid the tragedies investigated in this article.

---

Title: Circumstances and causes of death of hikers at different altitudes: A retrospective analysis of hiking fatalities from 2003–2018

Authors: Severin Zürcher, Christian Jackowski, Corinna A. Schön

Journal: Forensic Science International

Year: 2020

Link: https://doi.org/10.1016/j.forsciint.2020.110252