Episode 7 | The Great Human Roast: Ultramarathons in the Heat

What happens when you ask thousands of endurance runners to jog a small country’s worth of distance… in the South African sun?In this episode, we turned the thermostat up with Dr Henno Havenga, environmental scientist, and explored what really happens when ultramarathons meet serious heat. Using a thermal stress index, we map the temperature conditions runners faced along the route—because sometimes it’s not just a race, it’s a slow-motion human braai.We also look beyond the heat to the air itself, examining pollution levels on race day and asking an uncomfortable question: while runners are pushing their limits, what exactly are their lungs breathing in? From roasting road surfaces to the science of thermal strain, this episode unpacks how heat and air quality shape the ultimate test of human endurance.