Not getting enough sleep is a quick path to injury. Running and walking, as well as other forms of physical activity, increase the stress on ones body, and sleep helps our bodies adjust to and remove the stress.
For various reasons, during the past month I've been getting 4-5 hours sleep at night. This is a reduction from the 7 hours of sleep that is my normal. I thought I'd explain my "system" for getting back to my normal of 7 hours of sleep. If I get my normal amount of sleep, I do fine, but I get tired and fall asleep during the evening when I get less than my normal. So, here is how I get back to my normal amount of sleep.
1. I try and remove the factors that caused me to get less than my normal sleep.
2. Even though I may wake up after 4 or 5 hours of sleep, I force myself to stay in bed until I've been in bed for 7 hours; I frequently add 1/2 hour to cover brief interruptions to my sleep, the result being that I'm in bed for 7 1/2 hours. During this time in bed, my bedroom light is off, and I keep my eyes closed and allow my body to go back to sleep. I also don't read or do other activities in my bedroom, so my body associates the bedroom with sleep.
3. It usually takes about a week or two of forcing myself to stay in bed until I'm sleeping the whole time.
We all have different bodies, and it is likely that you may need a different amount of sleep to get your normal sleep. It is also likely that your body may react differently to being in bed.
The good news is that I'm almost back to my 7 hours of sleep. If you have suggestions that I (and others) might try, please leave your suggestions in comments to this post.