Binder to use for exercise

[FtMaster]

Hi everyone c:
My first binder came in the post today, it's an Underworks Tri Top in small. It was a pain to get on but once it was on it wasn't as bad as I had imagined it to be, and I loved the effect it had on my chest. However, I train in martial arts, and when I attempted to train in the binder I found it nearly impossible as I was out of breath within a few minutes, and was exhausted at the end of a 15 minute intense session (usually mine last 30-45 minutes and I'm relatively fine at the end). I usually train in a sports bra, however they make me feel extremely dysphoric. I simply can't train in the tri top, though. I was wondering if anyone knew of a binder that it would be possible for me to train in? I was considering buying the Ultimate Chest Binder Tank in a medium from Underworks to see if that works, however I simply don't have the money to just throw away on something that won't work. I measured my chest, and my under bust measurement is 30 inches, which would be a 34 inch bustsize, and over my bust is about 36 inches, which I believe (please do correct me if I'm wrong, I'm awful with clothing/bra sizes,) is a 34C (in European sizing).
Does anyone have any suggestions? I appreciate your help so much, and thank you in advance

[Carbonated]

You might give this a try http://www.underworks.com/extreme-magicotton-sports-and-binding-bra
Haven't tried it myself, but I might in the future, looks like it could work well.

[FtMaster]

I was looking at that binder, do you know if the number shown is under the bust or the band size? Clothing sizes really confuse me :')
Thank you for your help c:

[Carbonated]

If you klick size chart it says "Take a snug measurement over the fullest part of the chest over the nipples." so 36 inches around you chest= size 36
Glad I could help
If you wind up buying it, would you mind giving a review of it?

[FtMaster]

Ah okay, so relatively snug around my breasts would be about 34 inches - that's the point at which I could still squeeze down a lot more, but I'm not sure if that's what'd be best.
And I'd have no problem doing a review on it I just need to make sure I get the right size first, haha. Thank you once again c:

[Aiden In Progress]

I can give a quick review of this. I could breath pretty easily in it and it brought me down a size or two, but it made kind of a uniboob effect more than anything. That being said, I'm fairly large (D cup) so it might work better for someone smaller than that. The 997 is a little cheaper and works better. It's not quite as easy to breath in, but after you break it in a bit, it'd probably work better.

[Turlough]

I'm curious to hear a bit more about the Underworks MagiCotton binding sports bra myself. Here is my situation. I also bought a small tri-top binder, only in my case, I was out of breath and feeling nauseated before I even tried exercising. Considering that I am going to be in high altitude in the summer, that makes me very nervous.   I think I have possibly got one size too small and could exchange for a medium, however, I have another problem with the tri-top; I have kind of a short torso and it pushes down on my stomach, causing me to look like I have a spare bicycle tire around my waist, and it looks pretty terrible if I wear anything not baggy around the waist.  So I thought maybe I could try the sports bra, but all this talk about a "uniboob" has me concerned too. If I'm only around a B/C, will it be noticeable?

[Felix]

You might should give the uncomfortable binder some time to stretch. Every binder or bra I've ever had has gotten a lot looser after the first week or so.

If it doesn't feel safe you can try a larger size or something homemade. I had some crazy-looking binders that I made out of underwear or a swimsuit or sports bra or really any combination I was willing to attempt with scissors and sewing. I had some premades I paid too much for or got from kind transmen who were willing to share. Obviously anything you use has to work well enough for you to feel okay and keep wearing it, but don't be afraid to try strange things. Exercising is important and places a set of demands on your binder that some manufacturers obviously don't account for.