Can people with high bp or diabetes are in risk of getting heart attack if they exercise hardly everyday? i used to exercise a lot but i got a lazy lifestyle due to work. so, i got type 1 diabetes so, is it safe if i train aerobic exercises again?

The risk of having heart disease is higher with high blood pressure and diabetes. Exercising does lower the risk. I cannot tell you to exercise again without more details about your general health. Consult a doctor to get the answer. Most likely you will be able to exercise without problems and it probably will be beneficial, but I cannot be sure this end of the internet

Exercise should be part of your daily routine as unfortunately modern lifestyle and work conditions ( majority computer leashed) have taken away the ability of having meaningful exercise while working ( such as walking, lifting, carrying, etc). When it comes to intensity, starting low intensity and increasing gradually with the help of a physio or personal trainer would be best at this point.