Once I found this page, my fiance suggested I share my story in case it might help some of the people here.   My problems started in Feb 09.  I walked 20 ft down my hallway and when I reached the end was extremely fatigued, sweating and when I felt my pulse it was racing, probably over 160bpm.  I thought "this is it" since I have a history of heart problems in my extended family and told my fiance (then GF) to call 911.  I laid on the floor and chewed an aspirin before the paramedics came.  They put a 7-lead ECG on my and said it didn't look like a heart attack.  After they left I sat and rested feeling very embarrassed.   Over the next few days, my sleeping got worse and worse.  First I started just feeling a very pronounced heartbeat while lying in bed.  Then I started getting the "near faiting spells", that feeling like your falling, or you're about to faint, or that your heart just stopped for a second, or maybe that part of your lung collapsed?  Of course I've never actually had any of these things happen (even before my problem started) so I'm not sure I'm describing them correctly.   I was 38 at the time and I've always been very healthy, so I had to go find a doc.  Found one, he ran the standard tests of an 11-lead(?) ECG, full blood work and a "lets see" approach.  ECG was normal, blood work showed HDL/LDL way out of wack, and maybe slightly elevated sodium.  I started taking flax oil and a whole pile of vitamins.   My problems got worse, I started setting up Dr. appointments multiple times a week, he tried to tell me it a "silent acid reflux" and anxiety.  I'm usually a very laid-back person, so nobody was believing it was anxiety, but we went with it.  I started having more and more attacks, I started having them in the middle of the day (light-headed, pulse racing above 160, falling/sinking feeling).  I was afraid to be alone because I thought I was going to just keel over any minute.   If I even actually fell asleep I'd jolt awake after 2 hours with lack of breath, tightness in the chest, sometimes it felt like every muscle in my torso had simultaneously clenched as hard as it could.  Sometimes I woke up and just felt like my whole body was full of toxins (the way I felt at when I had mono).  Lack of sleep increased anxiety, and started making me completely irrational.   I got a 48-hr holter monitor and it registered completely normal, even during full-body episodes.  I was curled up on the floor suffering from shock at one point and the holted read normal the whole time.  We went to the ER twice, got zero treatment and a HUGE bill.  We called the paramedics 3 times and after the 3rd time they said "You gotta get this under control, go to your doc and ask for a tranquilizer or some kind of anti-anxiety drug".  I eventually did that and they prescribed a small amount of Alprazolam and put me on an SSRI and Ambien for sleeping.  That combined with Prilosec and a whole bunch of vitamins and other supplements (zinc, C, taurine, flax, etc)  I was taking 12 pills 3 times a day!  ...  and it wasn't getting better.   Then a friend told me to drive 2 hours to see this chinese nutritionist/naturopath.  I was desperate to try anything, so I got an appointment and I sat down with her and we just talked about everything.  Then without even an examination she put me on a food intolerance elimination diet.  It had the following rules: - No eggs or dairy - No soy - No nightshades (tomatoes, potatoes, peppers, eggplant, etc) - No shellfish - No red meat - No wheat gluten - No cooking oils  (if you must, use coconut oil) - No fake sweeteners (sucralose, aspartame, etc) - No MSG, hydrolyzed or autolyzed anything (i.e. autolyzed yeast extract, etc) In addition, I voluntarily gave up all corn and corn derivatives as well. She also told me to ween myself off all the pills since they might be masking symptoms that we want to fix rather than cover up.   My Result: Within 24 hours I'd dropped to half my previous dosage of prilosec, a my acid reflux was going away.  Within 48 hours, I'd stopped all the pills, and slept for more than 2 hours for the first time in 3 months.  Within two weeks, I was sleeping 8 hour days again, and my pre-sleep faiting episodes were dropping down to a lesser annoyance. At the 2 week point I started added foods back into my diet.  I started with nightshades, a big ethiopean dinner full of tomato and peppers.  I didn't sleep well that night, but I later realized that lots of working out (like the 35miles I rode that day) combined with lots of sun seems to make any episodes much worse that they would otherwise be.   I kept Alprozolam with me for the next 6 months, only taking a half pill if I was having a particularly bad night.  I think I only needed to actually take it maybe 3 or 4 times in those 6 months.   I also learned how to read my new body symptoms differently.  If I was having trouble sleeping, had a slight falling feeling, and the top of my head felt like it was spinning, that always meant that I needed to evacuate my bowels, even though I didn't feel it any other way.  I would always feel better afterwards.   Other oddity:  It gets worse in the winter time (well, cold weather maybe?).  During mid November 09, the weather got cold, I started having more pronounced symptoms more frequently.  I thought it was coming back with a vengance.  Then we take a family vacation down to the southern carribean.  I was fine the whole trip, slept awesome and not a peep of problems.  Then I come back home in December and the problems start the very night I returned.   Who knows, it might all be anxiety-related manifestations.  But haven't reached a point where I believe that yet.  I still believe there is some wierd condition that causes these symptoms in myself and others like me.  I believe it is digestive related, but it's something too subtle to be picked up by scopes, X-rays and the like.