I attended a CPR class today in which one of the instructors attempted to answer this question, "Do more heart attacks happen in the morning soon after people wake up?" She didn't tell us whether it's actually true or false, as far as waking up goes, but she did talk to us about a body at rest/asleep and all the energy required to run that body's system's upon waking. She ended up saying she could easily see how the simple shock of awakening and being pushed to function fully could trigger a massive heart attack.