synscope

I am a healthy 48 yr old runner.  I do 1/2 marathons and have no other health issues. I tried going to the gym with a trainer but kept having to stop 40 or so minutes into the workout due to dizziness.  At one point, the gym owner took my BP and it was very low.  I don't normally have issues with dizziness although I had to stop donating blood due to such longer and longer recovery periods.  I did also have issues with dizziness when cycling.  I never become dizzy when running though.  I have seen the cardiologist and he had me do a couple stress tests and then later a tilt test (today) which I quickly failed and passed out totally.  My heart stopped for 15 seconds when I was out.  It was suggested by this doctor that I should drink lots of water --2-3ltr a day and that perhaps either medication or a pacemaker might be recommended.  Any suggestions?  I'm going to do the water and when I run in the hot weather I'm going to take salt tablets to ensure I don't have issues in the heat.
Any suggestions or advice would be greatly appreciated.
Thanks.

[Jerry_NJ]

You mention failing the tilt test.  What did your doctor say about that failure?  

While dehydration can cause heart rhythm problems, I'd not guess that is a "fix" for dizziness.  

I'd talk with the doctor more before taking on any strenuous running exercises.

[ancasterguy]

Hi Jerry,
he told me the running was great, to load salt, drink more fluids and said the cardiologist would likely recommend meds and or pacemaker.  I don't ever get dizzy while running so I'm not concerned about that.  He was impressed that when I did the stress tests I finished both of them (15min).  I was exhausted mind you since they push you to maximum HR but I finished them.  The last one they had me immediately stop so they could image my heart (I had to lie on a table right away) -- that made me dizzy since I couldn't cool down and keep moving.  They said my heart was in great shape..just the synscope problem..