I haven't bouldered much in the past but I'm doing more of it now to get stronger. The problem I'm running into is that my warm-ups aren't sufficiently long and I usually have to end a session after about 45 minutes with a devastating flash-pump.

What I'm bouldering - flashing all V4s, taking 3 or 4 tries on most V5s, projecting V6s.

I'll usually warm up with 1 V1, 1 V2, 2 V3s, and a V4. Should I be spending longer on my warm-ups? Do I need to spend about 20 minutes just climbing and downclimbing the V0s and V1s? I'm sure I can figure it out on my own; I just want to know what works best for y'all.

I'm no physiology expert, but I find that climbing the bigger holds don't get me sufficiently warmed up. Generally, 100 climbing moves is the minimum before I jump on something close to or at my limit, particularly if the holds are small and tweaky.

If you are at a location where there are not many moderates, I will do a combination of things. Jumping jacks to get blood flowing. Clenching my fists tighter with each breath for 5 - 7 breaths. Pretending to flick water off my hands (Horst's conditioning for climbing exercise). Even grabbing a crimp on the wall while fully weighted on the ground to emulate climbing.

If you are getting flashed pump, maybe you are getting on problems that are too long?