On days like today, when I've only had 5 or 6 hours of sleep, I often wonder if it would be healthier (in terms of recovery, performance, and so on) to skip my lunchtime workout and take an hour nap instead.
Is it better to skip my workout when I'm sleep deprived and nap instead?
If not, should I make any alterations to my routine (such as focus more on strength movements, reduce the amount of cardio, etc)?
Well you aren't getting in shape by sleeping. Yes sleep is crucial to a good fitness routine but sleep is not making you more fit. Also 5-6 hours isn't terrible if it is just one night.
If you have 4 workouts you do a week and you will move this workout to another day I say do that.
If you will simply skip the workout, I wouldn't. Since you are more apt to injure yourself while being tired, I would adjust my workout not skip it. It also depends on where you are with your routine. If you are concerned about strength, just go in and get the weight work done with a lot less reps per set than usual. If strength isn't a concern then do your same workout with less weight, faster.
Cardio... No reason to skip it. I would first make sure it is done after lifting. Second, I might lay off the treadmill or running. You are more apt to pull something being tired or distracted. So try biking, elliptical, stair-stepper - things that won't stretch your legs/core as much.
You will sleep tonight much better knowing that you reached your workout goals even when a little tired.
You are talking about a nap for a whole 1 hour. Actually, this is not a true nap. Nap is about 20 minutes long, depends on personal preferences but the rule is that you (better say your brain) should stay in REM (Rapid Eye Movement) sleeping phase.
From my personal point of view, the best solution for your situation is to have a 20 minutes nap and then 40 minutes hard workout. This worked for me every time.
During afternoon hours one hour of sleeping can be total waste of your time. You will probably get up more "damaged" than you were before lying into the bed.
Some tips: You should know how long you need to fall asleep. For me (afternoon, after work etc.) is about 5 minutes. So I go to the bed and set my timer to 25 minutes to make sure I will be sleeping no longer than 20 minutes and will not miss the end of my very first REM phase.
My 2 cents :)
Like most things relating to strength training, it really depends on the person. I would say a good rule of thumb is to never skip a workout, regardless of physical/mental ailment. Often you will have to accommodate your physical/mental condition in your workout by decreasing the volume or intensity, but something relatively trivial as "I'm tired" isn't a great excuse. Save your skip days for days where it really counts.
It also depends on the goals you have for your training. If you workout to maintain a healthy body, than skipping a day isn't going to kill you. But if you plan to compete in your chosen sport than I would seriously advise adhering to the Never Skip A Workout Ever approach as it helps contribute to a winning attitude.
