First, this message board has been immensely helpful already. Three weeks ago, I shook my head way too vigorously and suddenly felt woozy. Severe exhaustion followed over the next week, with mild headaches, and dizziness when swimming.

As long as I stay faithful to the daily regimen of supplements endorsed by Mark from Idaho and get adequate sleep, I seem to be making gradual improvement, including some days where I experience no symptoms at all. I waited two weeks to resume any kind of exercise, which, since my symptoms were comparatively mild, seemed not very risky.

Since then I have ridden my bicycle three times, for 30-45 minutes each time. I am a road rider of moderate seriousness, so getting my heart rate up to the 165 to 175 beats per minute range is not uncommon for me. On these rides, I went straight back to that level. For the most part, I felt fine afterwards. Maybe just a tiny bit headachy, but the endorphin rush was more than worth it.

Then last night, our cat crawled under our bed. Laying on my stomach on top of the bed, I hung my head over the side to see him. Immediately felt the "heavy head" sensation that others have described, which has continued until today. I did read the thread on this board about the brain's impaired ability to regulate blood flow, which makes sense.

Are the perhaps premature exercise and head inversion unrelated? I will obviously lay low until this heavy head phenomenon diminishes, but I would really like to continue cycling, which seems low-risk, low-impact, and very heart healthy.