That's not my theory. That's the data.

One interpretation could be that women were constantly engaged in strenuous endurance activities and so through evolution built up tolerances against exhaustion that at least rivals if not exceeds that of men. And one historical activity that used a lot of stamina and took a lot of tolerance against fatigue was the way in which ancient humans hunted.

That's not what a theory is, it's a hypothesis at best, hope that helped.