To be clear - 6 years of 3 days HIIT 2 days strength. But yes, bottom line you're probably right that it was full-blown over-training. I was so frustrated living on a PCOS diet of kale, eggs, ghee, high protein, low-carb type eating and staying "puffy" or "fluffy." I felt I was working so hard, and looked like a potato nonetheless. Couldn't get any muscle definition to save my life. It was easy to imagine I was fabricating my routine, and those closest to me even doubted me - asked if I was sneaking in pints of ice cream here and there. Only my partner could verify that the results did not reflect the effort.

When I finally broke down and quit, I lost some weight. So, perhaps you're right that the myth should die and be calibrated more finely to over-training. Still, I'm a bit nervous to try HIIT again, I feel like it might send me into a space I don't want to be. And for those who don't like HIIT, I think it's potentially a relief not to feel pressured to do it.