On a recent trip to Kings Dominion, I experienced my first "grayout" on a roller coaster. After riding Grizzly, Rebel Yell, Ricochet (twice), Hurler, Backlot Stunt Coaster, Dominator, Avalanche, Volcano: The Blast Coaster, Flight of Fear, and Anaconda, I made my way to Dominator's station once again for my final ride of the day. Although I had taken some breaks throughout the day to ride the Blue Ridge Tollway and the White Water Canyon and I had even caught the Rock 'n' Roll show, I was quite tired at this point. Even so, I wasn't concerned that my Dominator re-ride would be too intense for me to handle. However, sometime during the vertical loop after the first drop, I experienced a momentary grayout in which I saw black spots. Fortunately, this sensation did not return later in the ride.
I attribute this grayout to exhaustion from the other coasters I had ridden before my second go on Dominator, particularly Anaconda, which had hurt my back on one of the turns after the MCBR. All the same, the grayout still spooked me, and it was difficult to enjoy the rest of Dominator because I was worried that I would grayout again, or even pass out.
I have been on coasters that are both faster and taller than Dominator before--Storm Runner, at 75mph and 180ft, comes to mind. I would assume that the whopping 135ft vertical loop on Dominator--one of the tallest vertical loops in the world--contributed to the grayout rather than its speed or drop height, though.
Despite the grayout, I would definitely go on Dominator again, though I would try to ride it at the beginning of the day so as to avoid an exhaustion-induced grayout. This is only a minor problem for me. A more significant dilemma of mine is my fear of Intimidator 305. I have heard from a number of friends that they experienced grayouts/blackouts on i305. Seeing as the drop height of i305 is about 150ft taller than that of Dominator and its top speed is 25mph greater than that of Dominator, I am wary of riding the gigacoaster. My thinking is that, if I grayed out on Dominator, I could very well pass out on i305.
As a side note, I find helices very intense, even on tamer coasters like the Backlot Stunt Coaster. However, I have not experienced a grayout on a helix before.
Given this information, do you think what I experienced on Dominator was unhealthy? Furthermore, is my concern about riding i305 rational? Where do I go from here? I would like to try out i305, but I'm concerned that it might jeopardize my health based on my experience on Dominator.