I used to jump right on and start huffing and puffing. My doctor and some of my friends told me not to do that. They explained that I had to have a Warmup Period in my workout. I am supposed to start very slowly doing some useless things. It seems to me that 10 minutes is a Long Warmup Period. What do you think?
Your friends and your doctor are right. You need to warm up before any exercise or strenuous physical activity. You have to prepare your muscles and your heart for the increased intensity and effort. And no, 10 minutes are not too long for warming up. Even 15 minutes are considered to be just about enough time to properly warm up if you are about to train hard and at high intensity.