The untimely passing of Dr. Harold W. (Bill) Kohl III on January 7, 2024, while he was spending time with family in Colorado, USA, leaves an irreplaceable void for his family, friends, students and trainees, colleagues, and the entire field of physical activity and public health research and promotion worldwide.
Dr. Kohl’s contributions to our field are innumerable. In terms of research and publications, his seminal work in the late 1980s on the effects of physical fitness on cardiovascular health and all-cause mortality, alongside Dr. Steve Blair, were essential for positioning physical activity and physical fitness as critical health protective factors. Further, his 2012 “call to action” paper in The Lancet remains the blueprint in our field used to identify priorities and assess progress in advancing physical activity research and promotion worldwide.1 With this paper, Dr. Kohl and colleagues were the first to define physical inactivity as a global pandemic, elevating its importance as a global public health priority.
In addition to his research contributions, Dr. Kohl was a passionate leader and advocate for national (in the United States) and international initiatives to help position physical activity as part of the “mainstream” in public health. He led the development of national and international physical activity guidelines, physical activity promotion plans, and international physical activity networks. A big thinker and a visionary, Dr. Kohl was the mastermind behind the creation of the International Society of Physical Activity and Health (ISPAH), which he established in 2008 and for which he served as the inaugural president. The Journal of Physical Activity and Health (JPAH) is the official scientific publication of ISPAH, and Dr. Kohl served as Co-Editor in Chief of JPAH from 2007 to 2011.
While the field of physical activity and public health will miss Dr. Kohl, I will especially miss Bill—my friend, mentor, colleague, and beer sponsor. Through this editorial, I hope to provide a glimpse, for readers near and far that only knew Dr. Kohl’s work, of who Bill was, and of his profound impact in our lives and careers.
Beyond all the accolades, positions, research projects, and publications, Bill was most proud of and committed to his students and mentees. Training the next generation of physical activity and public health leaders—and getting people from all corners of the world excited about this field—was Bill’s ultimate passion. Perhaps less known to some, especially here in the U.S., is his profound influence and immense commitment to supporting international students and scholars, and to helping advance our field and its leaders in low- and middle-income countries.
I was very lucky to call Bill my mentor and my friend. He was my biggest cheerleader and my most honest critic. I owe him many of my career accomplishments, including the opportunity of co-authoring my first textbook with him (Foundations of Physical Activity and Public Health)—a project that was remarkably close to his heart. As a mentor, Bill was generous and loyal to the core. What made him such an impactful role model, and an incredible leader in our field, was his humanity. He dedicated time and effort in getting to know his students and mentees beyond their research interests, and respected their career and personal priorities, even when they did not align with his own. I will never forget the day I learned my grandfather had passed away. I was a postdoctoral fellow with Bill at the time. As soon as he found out he consoled me, canceled all my meetings, finalized a grant submission he and I were working on, and booked a flight for me to leave that same day to Mexico City to be with my family. He never let me pay him back for the cost of the ticket. This is the type of mentor and friend Bill was, and in my mind, this was a big part of his success for all aspects of his career.
“Although Dr. Blair’s scientific contributions are apparent and readily available, less well-known is the influence he had on young scientists, particularly his support of young female scientists and practitioners. Leaders are everywhere. Those who distinguish themselves take the time to pull the next generation(s) up with them. This may be Dr. Blair’s most enduring characteristic. Dr. Blair was particularly influenced by the mentoring of Dr. Ralph S. Paffenbarger, which he then used as a model for his mentoring of others. Indeed, the field of physical activity and health is what it has become because of Dr. Blair’s leadership and attention to the next generation of leaders. For young scientists in the newly formed field of physical activity epidemiology in the 1980s, he was a hero. There is now a next generation of leaders emerging who, despite not knowing Dr. Blair, have been indirectly influenced by his enormous impact on the field.”2
To my observation, Bill responded, “You may be about the only person in the world to realize this.” I respectfully disagree, Dr. Kohl. The entire world of physical activity and public health is mourning your passing—in particular, your current and former students and mentees. Rest assured, your legacy will endure, and we shall carry the torch forward. ¡Hasta siempre Jefe!
