Zone 2 cardio: The exercise we ignored for years is suddenly looking like the smartest one
For the longest time, the fitness world had a simple, unspoken rule: if you weren’t drenched in sweat, you weren’t really working. HIIT was king. Boot camps were sold as the only honest hour you could spend at a gym. And that person on the treadmill moving at a comfortable, conversational pace? They were basically…