I've been having breathing trouble for the past couple years, but only
when jogging.  There is no wheezing, no coughing, just this feeling
like I'm not getting what I should be getting out of breathing, and
then lightheadedness and feeling like I'm going to pass out.  It's very
different than normal out-of-breath feeling. Also a bit of chest
tightness but it's not terribly obvious all the time, and after the
'attack' I feel congested in my lungs.  It comes on pretty suddenly
after about 8-10 minutes of running, and by the time I realize it
(basically just a feeling of overexertion), it's already too late.  I
stop and have to sit down trying desperately not to black out.  The
first time it ever happened and didn't know I had this problem, I
blacked out in the street after stopping to walk, sank right through my
knees for about a second before regaining consciousness (fortunately my
husband with me, after that I won't jog without him). It takes at least
5-10 minutes to recover from this enough to be able to walk home -
sometimes I have to stop several times along the way and sit down,
concentrating on breathing.  It's most frequent in spring, even early
spring when I don't otherwise get pollen allergies, and also in cold
dry weather, but is increasing in frequency this past winter.

I have an insane family history of asthma - my aunt and uncle had it
since they were little kids in a very severe form, and my mother
developed it in a milder form in her 40s after getting a second cat.
My brother also recently developed it, presumably triggered by exposure
to the cats.  They all have traditional wheezing symptoms.  I already
moved out by the time my mother started accumulating cats.

Just went to the doctor and he prescribed me an albuterol inhaler to
try out, but also recommended heart tests.  He was doubtful about the
asthma due to lack of wheezing and my sudden onset of seemingly severe
symptoms (fainting). Haven't done the heart tests yet but just had an
EKG about 5 years ago when I started working at a chemical plant, it
was just routine for their clinic but they didn't say there was
anything unusual.  I'm only 25 so I guess it's likely that anything I
have now would be congenital and also would have had when I was 20 and
had the EKG?  Last night I was doing some exercise on my balcony, first
major exertion since getting the inhaler a couple days ago, and felt
like I started to get an attack.  I took 2 puffs from the inhaler and
suddenly felt well enough again to continue.  I'm still not convinced,
so I'll try taking it before jogging, or maybe purposefully stimulate
an 'attack' just to see if the inhaler is doing something (but this is
scary!).

Does anybody have similar experiences?  Could this possibly be asthma
and if the inhaler stops an 'attack', would that definitely indicate
asthma?  Could I somehow be hyperventilating?

Thanks.