Are my workouts too intense? (Safe?) ?

My cardio workout is just a stationary bike ride for 25 or 30 minutes at 0 resistance.  According to my smart watch (FitBit) my average heart rate during it is around 180 BPM and my top heart rate is usually around 190 BPM... and I burn at least 450 calories in 25 minutes and if I go for 30 i burn over 525... show more My cardio workout is just a stationary bike ride for 25 or 30 minutes at 0 resistance. 

According to my smart watch (FitBit) my average heart rate during it is around 180 BPM and my top heart rate is usually around 190 BPM... and I burn at least 450 calories in 25 minutes and if I go for 30 i burn over 525 calories (573 is my record)

I average 10mph according to the bike 


Is this safe and healthy to do 2 or 3 times a week? (I’m 22 and a guy) 
3 answers 3