Heart rate

I do a fitness blender workout 4-5 times a week and walk my dog daily , just got a bike so the odd bike ride , my question is I read on another blog I need to do 3 x 45 min with heart rate 130-150 , is this right ? Iā€™m stressing now on how to fit that in as well šŸ˜©šŸ¤·ā€ā™€ļø