Thanks for writing your query to us.
Heart of 75- 80 is normal. Normal heart rate
is between 50 - 100 per minute. I would advise you to consult your Physician & get your Electrocardiogram done when you get this type of symptoms. They may also do a holter monitoring study for you if required which can record your heart rate for period of 24 hours while you are carrying out your routine or during sleep also. This will help to know whether your heart rate is fast.