When it comes to that aforementioned “post-workout glow” aerobic exercise tends to receive all the hype. After all, cardio gets your heart pumping, which encourages circulation. That’s why researchers wanted to compare aerobic exercise to resistance training, the latter of which hasn’t been studied as deeply. 

So in a study published in 3Scientific Reports3, scientists split up 56 healthy but inactive middle-aged Japanese women into two groups: one group completed aerobic training, and the other participated in resistance training twice a day for 16 weeks. 

The results: Both types of exercise plans improved skin elasticity and upper dermal structure; however, only resistance training was found to increase dermal thickness—and this structural integrity is crucial for supple, firm skin. Researchers specifically found molecules called biglycans in these participants’ blood samples, which are linked to skin firmness4. On the flip-side, they found a decrease in molecules that inhibit biglycans, like cytokines.

TL;DR? Both cardio and resistance training are top notch for healthy skin aging, but only resistance training was found to increase the thickness of the inner skin layer.