As climate change leads to record-high temperatures around the world, dangerously hot days are prompting questions about when it's too hot to exercise outdoors.
The stakes are high. The consequences of a too-hot workout "range from feeling thirsty to death," said Clare Minahan, a sports scientist at Griffith University in Australia. But figuring out when to trade that woodsy running path for the old treadmill is not as easy as glancing at a thermometer.