Reverse valve masking

I was exposed to Covid recently, so by University rules I need to mask for a while. I don't particularly love masking at the gym, but I found a nice solution. My go-to mask for physical activity during the pandemic was the Trend Air Stealth N100 respirator, with the valve replaced by a 3D-printed blocker. But now I don't need to protect myself, just others. So I simply put the valve back in, but in reverse, so I get clear air intake but my exhalations go through the N100 filters. The respirator was already pretty breathable, but now it's even better, though it still looks super-weird and I need to remember not to use the respirator with this modification when I actually need protection, e.g., when doing woodworking.