Mia Derstine, Denver/USA - Race Doctor

Dr. Mia Derstine is an emergency medicine physician with UCHealth at Highlands Ranch Hospital.  She did her residency at the University of Chicago.  She then did a Wilderness and Environmental Medicine Fellowship at the University of Colorado, where she is now the associate fellowship director.  Her academic interests include women in the wilderness, education, and plant toxicology.  She has experience with flight medicine, international medical transport, austere medicine at Summit Camp in Greenland, and ultramarathon medicine in Mongolia.  She is currently the co-chair for the Wilderness Medical Society summer conferences.  Her preferred vacation is walking for days on end with a (kind of) heavy backpack. You can otherwise find her at home in Denver with her husband and pup Ginger.

Mia already served as a race doctor at GlobalLimits Cambodia in 2023.

Brian Derstine, Denver/USA - Volunteer

Brian is a data scientist with the Morphomic Analysis Group at the University of Michigan.  When he's not at work analyzing CT imaging data using machine learning, he's either working on a DIY home improvement project, or participating in one of his other hobbies - cycling, skiing, fly fishing, bouldering, hiking, and camping. Otherwise he's at home  in Denver with his wife and dog Ginger. 

Sarah Siebert, Berlin/Germany - Volunteer

Sarah lives and works in Berlin and enjoys running, traveling, and making the most of her gym membership. On occasion, she can be found hiking through the Albanian alps, the Amalfi coast in Italy, or the Troodos mountains in Cyprus.

Over the years, Sarah has volunteered at numerous races, putting her professional experience as a Supply Chain Manager to good use. She joined the GlobalLimits crew in 2024.

Stefan Schlett/Germany - Volunteer

Stefan is a life long adventurer and celebrates the art of extreme-sports since the age of 19. After school he worked 4 years as an retail salesman, before he joined the German army for 5 years as an paratrooper. The army service functioned as an exit from normal life and after that he never came back to a ordinary life. As a ‘freelance-adventurer‘ and freelance writer he was a Pioneer in extreme-sport in Germany. He was the first German participant in several events famous at the time in the ultra-scene (e.g. Western States Endurance Run, Badwater Race, Grand Raid, Sri Chinmoy 1300 mile run, Marathon des Sables, Tough Guy etc.) and made these events known in Germany through his publications. At the end of the 80s, he set a dozen German records in the street run, from the 6-day to the 1300-mile run, as well as in the deca triathlon (tenfold Ironman), which he would hold for a decade. At his most active times he practiced the following disciplines: ultrarunning, skydiving, mountain-climbing, triathlon, inline-skating, ice swimming, kayaking, staircase running, swimrun, obstacle races, mountain-biking.

Noteworthy Accomplishments:

- 507 Ultras + 209 Marathons in 67 countries, totally more than 2000 competitions in 97 countries

- Former World Records: Marathon and 50k on a cruise ship; treadmill – 111k in 11:11 hrs; Run Up automatic downhill-escalator – 21.403 stairs/5000 m altitude; Ultramarathon in the underground (700 m below the surface in a salt mine)

- First human to traverse 4 continents (three by foot, one by mountain bike) by human power, under competition rules: Trans-America-Footrace from Los Angeles to New York 1992, Trans-Australia-Footrace from Perth to Canberra 2001, Trans-Europe-Footrace from Lisbon to Moscow 2003, Tour d’Afrique from Cairo to Capetown 2005

- Climbing: highest mountains in 45 countries and 5 continents; highest mountain: Pik Lenin/7134 m in the Pamir Range

- 496 skydives all over the world, including one at the Northpole

- Travelling: roughly 120 countries travelled, 400 islands visited, 400 mountains climbed

Stefan already served as a volunteer in GlobalLimits Albania and Sao Tomé.