Lack of Stamina

[Azpb Djbread]

On Stepmania when i play really well, i can FC the first half of the "Sterio Sayan 3D" file (being the lower level of the file, so it is playable), or the "Call me It (500 Tortures)", i can FC the first 25%-30%, or with Hi19Hi19's Blastix Riotz, i can FC the first half, or the Fautxp,c[zx (or whatever the name of it is) i can FC around the first quarter / Half, and the "Never Again" File from the etterna pack i can FC if i dont lose stamina, but i just get so tired so quickly. Any tips on how to maintain stamina? Because i feel like i can do really well if i were to not get so tired so quickly. I'll do good for the first 30% of a file and have to end it abruptly because my hands just feel really sore.