dear friend, welcome to HCM.
do not worry. heart rate
increases in response to any exercise/ activity and can go very high, esp at your age.
rarely abnormal heart rhythms (arrhythmias )can present like this with dizziness
so relax now and take it little easy. if such episodes repeat, esp. with fainting
, pl see a physician and get an ECG.
I hope to have satisfied you.
take care and keep me posted.