About Us

Since 2012, GlobalLimits had been organizing multi-stage races in Cambodia, Bhutan, Sri Lanka, and Albania. São Tomé is organized in 2020 especially for qualified runners.  Our goal is to combine running with local cultural appreciation – that is, all our race locations have spectacular historical backdrops and there are always opportunities to stay in local homes.   

Our team, including our volunteers and local partners, are experienced runners or event organizers; we have proven track records in organizing successful multi-stage races.

Our professional medical team specializing in wilderness and emergency medicine will provide you necessary high-standard medical treatments during the race week.


Stefan Betzelt/Germany - Founder and General Manager of GlobalLimits

Stefan was born and lives in Wiesbaden/Germany. He founded GlobalLimits in 2012. Stefan has a wealth of extreme racing experience, having participated in many of the most gruelling ultra races, such as Marathon des Sables, Les Foulees de la Soie, Himalayan 100Mile Stage Race, Racing the Planet Namibia and Desert Oman Raid. He also participated in about 20 city-marathons (PB 2:46) and successsfully climbed the Kilimanjaro and the Mount Aconcagua.

Stefan has visited more than 92 countries and learnt a great deal about different cultures and people. He now makes use of this experience to select outstanding and unique locations for the GlobalLimits races.

Stefan has worked as a managing director for some of the leading global financial institutions before he retired in 2004 to become a self employed financial and personnel consultant.

Stefan is also a member of the Curatoship of the Institute of Sports Medicine in Frankfurt/Germany.

Mario Machado, Lisbon/Portugal - Course Director

Mario, a physical Education teacher and international athletic coach, is the technical director of the Lisbon Half Marathon (30.000+ runners), the Portugal Half Marathon, the Lisbon Marathon and the organizer, technical director and controller of the race of various other high profile road races in Portugal and international trail races.

Since 2009 he is also the "Controller of the race" of the Marathon des Sables in Morrocco.

Mario is the publisher and director of "Spiridon-Portugal" running magazin since 1978.

He is also a very experienced runner himself. He just finished his 100th Marathon/Ultra at GlobalLimits Cambodia 2017.

Mario already served as a volunteer for the inaugural race in Albania in 2017 and in Cambodia 2018 as well as being the course director in Albania 2018 and 2019 and Sao Tome 2020.

Ryan Paterson, Denver/USA - Medical Director

Dr. Ryan Paterson attended the University of Vermont School of Medicine and completed his Emergency Medicine Residency and Fellowship in Wilderness/Altitude/Expedition Medicine at Denver Health Medical Center/University of Colorado. He also holds advanced certifications in Tropical Medicine from the London School of Tropical Medicine and Hygiene (DTM&H) and in Mountain Medicine (DiMM). He is a practicing Emergency Physician for Kaiser Permanente at St Joseph’s Hospital in Denver, Colorado.

Dr. Paterson serves as co-course director for the Wilderness Medical Society and Universities of Colorado and Utah’s Diploma in Mountain Medicine Course (DiMM). He is the current United States delegate to the International Society of Mountain Medicine (ISMM). Currently, Dr. Paterson is working, in partnership with CU South Denver to develop a Wilderness Medicine for Kids program utilizing an original curriculum. He also serves as medical director for No Barriers and another non-profit (Kolkata City Mission) working to establish sustainable development solutions in education, health, women’s empowerment, micro-enterprise and public-health for informal communities in and around Kolkata, India.

Ryan already was our medical director in Cambodia 2016, Bhutan 2017, 2018, 2019, Albania 2018, 2019 and Sao Tome 2020.

Mafalda Iria, Portugal/Sao Tomé - Volunteer

Amy Paterson, Denver/USA - Volunteer

Amy is the mother of two active girls, married to Ryan Paterson, GlobalLimits' medical director. She works as an Elementary School Teacher. In addition, she volunteer coaches soccer and lacrosse for young girls in Denver. She has supported and volunteered for numerous running, cycling, and triathlons races.

 She was an All-American lacrosse player in high school and college and loves working as a team. She is truly inspired by athletes competing in ultra-marathons and is excited to volunteer. Amy loves to travel, be outdoors and is always up for an adventure.

Amy already served as a volunteer at GlobalLimits Albania 2018.

Martin Nobbs, Great Britain - Volunteer

Mayra Johnson/Brazil - Volunteer

Born and raised in Brazil, living in Asia for the past 17 years, currently in Mumbai (India). Professional background in the Airline Industry and Finance. Currently working in the Fitness Industry as a Pilates Instructor and as an active volunteer at an orphanage for girls in India.

Found the love for running 5 years ago, specifically for the multi stage races. Completed a few full and half marathons and the following a couple of Ultras including GlobalLimits races in Sri Lanka, Cambodia, Bhutan and Sao Tomé. Mayra is also a winner of the prestigious "GlobalLimits Heritage Site Runner" series award.

Mayra already served as a volunteer at GlobalLimits Albania 2019.

Tiziano Pisoni/Mucumbli Explore, São Tomé - Logistics & Infrastructure