Why Is It Advised To Take Ramipril At Bedtime?

I am 62, 6ft, 185 lbs. I had a heart attack on Jul 1st, 2014. I had two stents put in, one in the right artery down low, and one in the middle. When I was 50 I did not have a heart attack but I was a walking heart attack. I had a stent put in my left artery. One of my drugs is ramipril. I used to take 5 mg everyday in the morning. After the last heart attack I am down to 2.5 mg. and the label tells me to take the pill at bedtime. What is the reasoning behind taking ramipril at bedtime now? Thank you.