Hi - I Was At A Baseball Game This Afternoon.

Hi - I was at a baseball game this afternoon. It was 100 degrees out and our seats were in the sun. I was a little hungover in the morning but felt better when we went into the game. It was very hot so I got a Minute Maid frozen lemonade (probably very sugary). As I was sitting watching the game, sweating, my Apple Watch sent me the heart rate notification - that my heart rate was 120+ while inactive for 10 mins. I have been checking on it since then and its been normal. Is it possible it was the heat or should I be concerned?