
The National Sleep Foundation defines sleep inertia as "the feeling of grogginess and disorientation that can come from awakening from a deep sleep." It slows down your decision-making abilities, impairs your memory and hurts your general performance once you do get out of bed. The impact can be felt throughout the entire day. You throw off your whole circadian rhythm when you interrupt your sleep cycle, because you re-set it and start over when you hit snooze or when you re-set your alarm. Do this enough times on a regular basis, and you're not just making yourself dumber through the day, you are putting yourself into sleep debt. Chronic sleep deprivation. And THAT correlates to a higher body mass index (ie: makes ya fatter).
When I'm in a consistent routine of waking up early, it's the easiest to just get out of bed. Even when I'm still sleepy and groggy. Last summer, when most of my workouts or classes were in the mornings (early, early mornings), I got myself into the best routine I've had for years. Wake up, hop out of bed, never look back.
Lately, I've reverted to more after-work classes at the gym, leaving my early mornings open. While I've tried to maintain the habit of getting up at the same time, what I inevitably end up doing is re-setting the alarm. Negotiating with myself. The list of things I was going to do in the morning? Meh. Can wait. Always seems less pressing in the wee hours than it did the night before. And so I go back to sleep. Again and again.
The problem with this method is that it interrupts the regular sleep cycle. The boys at ASAP Science explain it well in this video. (And, shout-out here to former camp staff Greg Brown, who is the illustrator of these videos. While I'm terribly proud of him for the success of ASAP, I can't help but picture the young camper I watched grow up, when I see these. Thank goodness he grew into one smart dude. You can trust the science.)

At some point I should just acknowledge that I'm probably going to go back to sleep, and set my alarm accordingly, so that I am waking up at the time that I intend to get up.
Starting this week, four of five weekdays will be early-ish workout mornings. It's only Tuesday evenings that are the consistent class time at the gym. Which is why, this morning, I set the alarm for 5:45 am ... and then again for 6:15 am ... and then again for 6:50 am ... and finally got out of bed and got going well after 7:15. Best intentions, and all. Didn't help having the rain pounding the window, and without a pressing reason to get out of bed, it was pretty hard not to re-set the alarm. Next week? I'll just be more realistic and set the alarm for a decent time, allowing for a sleep-in, without interrupting my sleep cycle over and over and over.