A couple of times after riding hard/fast i've noticed I've started to hyperventilate and feel like I can't get enough oxygen

even when i stop riding completely I still feel like i'm gasping for air

what is the best/fastest way to recover from this?

Go to the Dr and get checked for Exercise Induced Asthma.

Hyperventilation was the trigger for me to do that. First it started with coughing a lot after hard efforts, and coughing a lot after cooler rides, and I suspected something was wrong. Then it moved into hyperventilation, and I went to the Dr, was diagnosed EIA, and got ventilators.

Until your Dr appointment, however, when you start to hyperventilate, slow down or stop and focus on exhaling. Exhale hard through your mouth.

i did read about Exercise Induced Asthma when i did a search. unfortunately i live in the USA and can't afford a doctor, especially for something as minor as getting winded when exercising vigorously

It's actually not that minor of a situation ... or at least, maybe it is right now, but if it is EIA, there's a good chance it will get much worse.

Can you move to another country where you can go to a Dr any time you want?

But meanwhile, try the forced exhaling and see if that helps.

Asthma and hyperventilation are not the same thing or have anything really to do with each other. I've done both. Asthma may be what the OP is referring to, just with the wrong terminology. The simple test is to take a deep breath and exhale hard. Do you hear a wheeze? If you do, asthma, if not, something else.

Something else:
When one goes really hard, one's energy production pathways change from aerobic to anaerobic. One can make energy without oxygen, but one's body doesn't seem to know that, and one feels one is in "oxygen debt" which one attempts to make up by breathing very hard and fast. One is actually trying to get rid of CO2. In this case, it's best to get control of the breathing by conscious deep breathing. When breathing in, start by inflating the belly, then the mid-chest, and finally the upper chest. Most folks, when they breathe hard and fast, only move the upper chest. This is incorrect. Slow the rate, and breathe deeply. This is the way to breathe when climbing.

One can also get in the habit of breathing every so many or even on each pedal stroke or footfall and then continue to breathe that rapidly even though one's effort has decreased as the road has leveled or one has stopped or whatever. This is true hyperventilation. It's unnecessary. You may feel dizzy. In this case, the simple solution is to gently stop breathing and just let your chest be quiet. The urge to hyperventilate will pass quickly if this is the cause.

yes, it commonly happens after i climb an overpass or do an all out sprint. it's usually after i have stopped exerting myself but i'm still breathing heavily because i'm tired. they i will start to get dizzy

I'm familiar with controlling hyperventilation when not doing exercise, it's really hard to slow your breathing when you've just done a bunch of strenuous work

Maybe you're just not in good enough shape to do that level of effort.

Eventually your cardiovascular system is so strong that your legs can't keep up and this won't happen anymore unless you just go super crazy, at which point, yeah, it's normal to feel dizzy, breathe heavy and see spots. Because that's what happens when you raise your heart rate to the limit.

Track your HR while this happens and see if it's something crazy like 90-95% of your max. If you get this while at 70-85%( or less) then maybe that's trouble, I dunno.

It's not clear that you're hyperventilating vs simply recovering from an anaerobic effort. Everyone breathes hard after a sprint. The dizzy feeling could be explained by your stopping after a hard effort. It's not uncommon for people to feel light headed with an associated drop in blood pressure if they stop immediately after a hard effort.

Rather than stopping, keep pedaling at an easier pace after a hard effort. Your breathing will still be heavy for a couple of minutes while you recover but you shouldn't feel dizzy.

Go to the Doctor for a sports check-up that might be cheaper.

Then IF everything is OK then concentrate on your exhale and the inhale will take care of itself. Use your diaphragm to force the air out.

yeah i dont stop completely.. i think it's less dizzy and more anxiety from feeling like i can't get enough air. i think focusing on breathing out as much as possible is good advice.. i'd been trying to hold my breath/slow my breathing, knowing that the more you hold it, the more co2 leaves your bloodstream, but holding your breath is really hard when you're out of breath.

my legs probably have more power that my lungs since i ride a pedicab which has built up my legs but i rarely am i getting an aerobic workout

As I recall speed of respiration is stimulated by C02 levels in the arterial blood. Hyperventilation is not caused by lack of Oxygen. If you push yourself hard, you cross your anaerobic threshold.
If you are burning carbohydrate, you go from C6H12O6 + 6O2 to 6CO2 + 6H2O + 36 ATP. You generate some C02 but it is manageable and you might breathe deeply and quickly but most of the CO2 gets wisked out as the venous blood goes through the alveoli of the lungs. But when you go anaerobic things change. You go from C6H12O6 and to 2 pyruvate and 2C02 and only 2 ATP. Now this is just about only 1/20 as productive in energy (ATP) as respiration and it generates 66% as much CO2. Now by using anaerobic processes, you can generate up to 100 times the energy as you can by respiration but only for a really short time. So if you go anaerobic you can see that you will be consuming lots of carbohydrate (C6H12O6) and generating energy very inefficiently and producing piles of C02. When your sensors in your blood see all that C02, they go YIKES and really crank up your rate of respiration.

Now you can do some additional reading. But it is my guess that you are going anaerobic and the resultant C02 generation is just making you pant until you blow the C02 out of your blood.

so how do i keep my self from "going anaerobic" ?