Bellamy summons his power by transforming parts of his body into spring and use it at will. I just think if Oda one day makes bellamy turn his bloodstream into spring for whatever purpose, I will not think it is bad writing.

Gear 2 widens luffy’s veins, increasing blood flow. Bellamy cannot stretch anything

Actually, gear second, Luffy uses his elastic properties to pump his blood, making it flow faster through his body, hence the life shortening concern.

In order to pump more blood at an increased rate, luffys veins need to be stretched

You should see the animation of Luffy's limb turning into a spring-shaped formation when he uses gear second. Sure, it'd make sense if Luffy's could widen his bloodstream of his whole body somehow with his ability, to facilitate the flow of blood. But I think fans here are more focused on the "pumping action" that triggers gear second.

No... His veins are not springy from what we know, it also makes no sense lol

The properties of rubber are very different from spring.

Actually you're right, I just realized, pumping action is different from spring. I mixed them up. my bad.

I was replying to the original post, not you lol @SkywalkerTC

Ya I blame the original post as well😡

Although springs could be packaged like a pump.... They're fundamentally different. And making bloodstreams into springs certainly wouldn't aid in pumping blood.