[ShelaVenna]

This is a kind of an odd question, but I’ve always wondered about it, and it surprises me that hardly anyone ever mentions the exact pressure they’re using. My pump measures pressure in inhg and “bar”. Lately I’ve been taking it easy and pumping only to 2 inhg for most of my “high pressure” session. I pump up to 3 inhg for a very, very short amount of time a few times per hour, and then go back down to 2 inhg. I follow that up with a much longer low pressure session using an electric system. What pressure do you use, and for how long? Do you cycle up and down in pressure? Do you take breaks? Do you find you consistently get more swelling at a higher pressure? At what pressure do you start experiencing side effects and what are they? I’m just curious. It’s amazing that Noogleberry has been selling gauged pumps for so many years, but basically no one ever references the gauge measurements in their posts.

[ShelaVenna]

I figured I might as well use this thread to write about some of my own experiments with different vacuum pressures. First of all I should say that I don’t just pay attention to the pressure gauge on my pump, I also pay attention to the cm/mm “ruler” on the side of my domes. The ruler on the cups is another pumping related measurement that I’m surprised no one ever mentions in their posts. 

I’ve been pumping again consistently for only around 4 weeks. On the first day, my breasts only swelled about 4.5cm into the domes. That might not be exactly right, because I didn’t bother to write the measurement down, but it’s close enough. Over the next 2 weeks, I realized I was consistently swelling 1 to 2mm deeper into the domes every session. By the end of week 2 I was swelling 6.3cm total into the domes. At that point, the swelling plateaued. I didn’t swell any deeper into the domes for about another week and a half. The stagnation seemed like a bad thing, so I decided to experiment a little bit with higher pressures.

For the first 3 and a half weeks I only pumped at 2inhg (which is equivalent to about 51mmhg). A few days ago I tried pumping up to 3inhg (76mmhg) every 15 to 20 minutes, and then IMMEDIATELY dropping back down to 2inhg. I tried keeping the pressure at 3inhg for a minute or two at a time, but that caused radiating nerve pain in my arms. (For those who don’t know, there’s a bundle of nerves and an artery towards the front of your armpits that you need to pay close attention to while pumping. Ideally you should not be feeling anything in your arms while pumping. It’s normal for the areas in front of your armpits to be a little sore while pumping, but if the pain, numbness, tingling, etc starts to spread into your shoulders and/or arms, that’s a sign you’re causing potentially permanent damage to your nerves and circulatory system). I found that occasionally pumping up to 3inhg and then immediately dropping the pressure, caused the swelling to increase another 4mm in one night, up to a total of 6.7cm. After around 2 days of doing that, I decided it probably wouldn’t hurt to very carefully try out even higher pressure. 5inhg (127mmhg) is generally considered to be the absolute maximum safe pumping pressure, but regardless, most people can only handle it for a very short amount of time before they start experiencing major side effects, like blisters, burst blood vessels, shooting nerve pain, and so on. I tried pumping up to 5inhg slowly but not too slowly. It only took about 2 minutes for me to reach 5inhg. Pumping even more slowly, would have been less safe, not more safe, because I would have spent too much time in the painful range between 3 and 5 inhg. Once I reached 5inhg I immediately dropped back down to 2 inhg. Then I cycled between 3inhg and 2inhg throughout the rest of the session. Like I said before, I didn’t keep the pressure at 3inhg for anymore then a second at a time. I immediately dropped back down to 2 inhg after hitting 3inhg. This method instantly made my breasts swell about 8mm further into the domes. That is a lot, considering I was increasing a maximum of 2mm, or a little over 1mm on average, per night before then. Unfortunately the “ruler” on the domes stops well below the top of dome, at 7cm. If I swell beyond 7 cm, I have to guess at the measurement. I’d say my swelling topped out at around 7.5cm. I’ve tried other methods to increase swelling during pumping, like heating pads, massage, and drinking excessive amounts of water, and it didn’t seem to increase my swelling very much, if it at all. This is the first method I’ve tried that actually worked.

TLDR: 2inhg (51mmhg) is a relatively comfortable moderate pressure. Higher pressures cause more swelling (no shit Sherlock), but they also cause a lot more pain and side effects. Anecdotally, some people claim that pumping at higher pressures too often and for too long, eventually causes a paradoxical loss of swelling due to tissue damage. I’m not sure why or how that would happen, but it has been claimed. Pumping up to higher pressures (not above an absolute maximum of 5inhg) and then IMMEDIATELY dropping back down to a moderate pressure, seems to increase swelling a lot without increasing side effects at all, and it’s nearly painless. Please let me know if you try it, and whether you see an obvious increase in swelling.