Regardless of any research done about this issue, I agree with you that doing both it’s counterproductive. I often see many people on treadmills, bikes, ellipticals, etc. who like to read while they are exercising and it makes me wonder. It’s impossible to do both and get a great workout out of it. There is a time to read and then there is a time to workout. It’s like driving and texting (or reading). Sometimes multitasking is not the most efficient way to accomplish a task. On the other hand, listening to music can be very effective and beneficial. I like to keep things simple.