Sudden change in response to different types of exercise?

shelbyforsquares

I've actually been an MFP member for quite a while now, but never posted here, and never even spent much time lurking.
I've done pretty well so far, and from my (pre-MFP) heaviest am down 105+ lbs.

I know the tail end of the weight loss journey is the biggest struggle, but I've had an odd change in response to different types of exercise (cardio vs strength) in the past 10 lbs or so that seems weird and inexplicable.

I've been doing both strength and cardio all along, altering the routine for intensity as I go, and up until recently seemed to get a much more noticeable payoff from the cardio. I've always carried muscle fairly easily, so just didn't seem to need as much strength training (though I absolutely admit my core is in crap condition and I need to work on that).

So, I've been doing more cardio, since I seemed to need a minimum of 4 cardio days a week for the best results.

Lately though, things have flipped. Even at higher intensity, I seem to be getting almost nothing out of the cardio, but even 15 minutes of strength work seems to be giving significantly better results.

I guess I can't get my head around it. I'm wondering why the sudden change. Can anyone explain what causes a sudden change in responsiveness like this?