In the last 6 months, it has happened 3 times during casual volleyball games where my heart rate suddenly spikes from a normal heart rate to about 170 bpm, and I feel light headed. It lasts for roughly 2 minutes, then drops back to a normal rate. The first time (about 5-6 months ago) during volleyball was when I dove, and the "episode" seemed to start the instant I hit the ground. The second time (about 2-3 months ago) was during volleyball, and it seemed to instantly start right when I spiked the ball. The third time (earlier today) it seemed to instantly start right when I hit the ground from diving. I don't recall this ever happening to me prior to 6 months ago. Should I be concerned? I'm a 27 year old male, and I'm in decent shape (5'10", about 160 lbs). I don't always eat very healthily, but I'm regularly active, and am involved in sports year round.