Fast Acting Insulin Only?

I am not on an insulin pump. But my understanding is that it uses fast acting insulin throughout the day. My question is do any of you use only rapid acting insulin, no long lasting? If so, how do you manage that and are there advantages to using just fast acting? Also, I have the same question in reverse. Does anyone use long lasting insulin only? Currently, I’m using both. I was just curious as to how and under what circumstances either of those option would work, and any benefits?

Before going on an insulin pump I mistakenly thought a working pancreas simply held insulin, then delivered a “surge” when you ate. When I chose to go on a pump I learned that was not the case - the body of those without Type1 is producing instantly constantly in the background, at just the right rate, which pumpers refer to as basal insulin. I was on target about what happened when you ate, although it is called a bolus and we determine the amount by counting carbs and using a formula based on our carb ratio.
If you take injections you use long acting background (basal) insulin since your body does not produce its own (actually it might do so sporadically for a while but eventually that will stop). And when you eat you take some short- or rapid-acting insulin to cover the carbs you took in - only rapid acting insulin is used in pumps but both can be used for injection - your doctor will determine which you should use.
Long-acting insulin is not used in pumps because a) it would clog and impede delivery and b) it’s not needed since you have insulin (rapid) infusing constantly. When you get a pump you work with your doctor to determine what your basal rate/s and carb ratio/s will work best for you - you may have more than one.
You might like to check Think Like a Pancreas. The author has Type 1 and works in the field of diabetes. It’s educational and a fun read and it does help explain pumping. If you think you might be interested talk with your doctor or nurse educator.
I was diagnosed in the early 1960s and took only long acting insulin until I started multiple injections shortly after college. BG meters came out around the same time but until then we tested our urine but not blood sugar as we do now. I can only assume my body was making some on its own as I lived to do fingersticks to see how I was doing. I think multiple daily injections are standard now but others on the forum who take shots can give you that information.
The only time I use long acting insulin is if I go off pump - I have insulin pens for basal insulin plus what I would need for meals. I hardly ever go off pump but some people take pump vacations from time to time. It’s not necessary - or safe - to get your insulin with both a pump and by injection at the same time.

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Hi @TiJoy a pump has a clock and it gives you a fraction of a unit every so often depending on your programming. For example I use a basal rate of 1.0 units per hour, the pump delivers approximately 0.035 units every 2 minutes or so. When you eat, you put in the carbs and it gives you say 5 units for that sandwich it gives you those units all up front over about a minute or 2. So a pump simulates long acting by giving you micro infusions of fast acting. T1 requiring insulin needs background insulin(long acting). Or a fancy pump, PLUS meal time insulin. You will not get good results on long acting only. Hope this helps.

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Very helpful, both. Thank you.