How come we get so fatigued when we are depressed?

I often wonder what it is that we get so tired when we get depressed.  I mean physically and mentally tired.  I had noticed that a few threads were about people sleeping and staying in bed all of the time.  I know when I get depressed that I am mentally and physically exhausted.  I know that the serotonin level has something to do with it, but does it cause physical exhaustion too?  I was wondering if others tend to get fatigued also.

Thanks and hugs

getting by

Sometimes I wont leave the house for weeks. It gets so hard doesn't it.
hugs
Karen

i always feel fatigued(word?). before i used to not be able to sleep at all and would just stay up all night, or recently now i don't wake up until 11am or noon. its really a bad thing. i cant get up any earlier because im just so tired. and i constantly feel depressed. you're not alone...

I read something lately about lack of deep sleep lowering serotonin levels. Lower levels of serotonin are also associated with depression. The serotoninergic system modulates mood and emotion, as well as sleep and appetite. Apparently the less serotonin you produce the more tired you can feel. Staying on as close to a regular sleep schedule as you can is supposed to help - going to bed and waking up at the same time, as well as getting regular physical exercise.
For anyone who doesn't know (though I'm sure most of you do) SSRI's (selective serotonin reuptake inhibitors) like Paroxetine and Fluoxetine work by blocking the transport of serotonin so it cannot be taken back up and re-absorbed into the synaptic pre-terminal. This means higher levels of serotonin, which is why drugs like that help treat depression.

Now that the days are finally getting longer I would think that I'd be doing better. But, I've also been feeling tired lately. (Plus, I haven't been keeping up with my exercise program. I had started to do Yoga at least once a day wanting to get up to twice a day, but I've kinda slacked off. The days I was doing it, I felt great!) But, now I've been falling asleep on my couch at 8 o'clock at night and waking up at 4 a.m. My internal clock is all out of wack! I've also noticed that when I have things planned that I look forward to I have more more energy and motivation. But when I don't have anything fun planned and all I have to look forward to going to the laundry mat to wash my clothes, I'm not particularly motivated to get out the door. I'm trying to keep expenses down, so I can save up money to out a down payment on a house, so if anyone has any suggestions for winter time activities on the cheap, I'd love to hear 'em! (I already go to the library to get books and videos and I don't have that many friends, so my options seem pretty limited.) I would love to go snowboarding, but I don't own a board and lift tickets are way too pricey! Maybe I should try to sell some of the stuff I no longer need and get a board or at least snow shoes! :)

Thanks for the suggestion Floppington! I never thought about skating! And we have an arena right in town! I'm gonna check it out next weekend, since it looks like that have open skating on Sunday afternoons for just $5. I'd have to rent skates, but they can't be that expensive if it only costs $5 to skate, right? I think I'm gonna finally sell some of my books that are just sitting around collecting dust to the used book shop in town too. I can then put the money towards some fun stuff and some not so fun stuff like bills! :) It just seems so hard to find a balance between saving money and finding fun, relatively cheap things to do! I mean I can only watch so many movies or read so much before I'm itching to do something different. Maybe I have a really early case of spring fever, since I don't own any crampons and I'm dying to get outside! I've also been thinking about just going to the mall to people watch, while leaving my credit cards at home, so I'm not tempted to buy anything! Thanks again! :)