How do you know you are overtraining?

mood changes / depression, inability to recover, weight changes, general fitness loss/inability to produce power, among other things.

It's also pretty rare in a "recreational" athlete. Not unheard of, but unlikely IMO.

You're going to be tired if you are training quite a bit. It's normal. I don't remember the last time I felt "fresh" on a workout.

Are you taking any full days off?

I have in the past found myself almost unable to give myself a day off....I would just go very light or short some days cause I'd have the time and figured I'd get out.  But I found the dead legs and tired body feeling would never leave.  Lately I've been forcing myself to take at least one full day off per week with no discernible exercise other than chasing the kids around and stretching.  And it has worked wonders for me.  The day after that day off I'm refreshed mentally and physically and ready to get after it.

Funny this came up today. I was on my long run for the week this morning and just felt weak. Now I did a hard ride yesterday and it was very, very humid here in LA(Lower Alabama) this morning. I walked a lot, and just kept reminding myself that I am going to have days like this.

My rest day is tomorrow!

1. Sleep Quality

2. Heavy Limbs

3. Appetite

4. Soreness

5. Overall Fatigue

6. Motivation to train.

From a scale of 1 (poor) to 5 (very high), if below a 3 on average, you're probably need to ease up or rest.

Just took a look at your logs - around 10 hours last week - is that a high in terms of volume for you? If so, you probably aren't overtraining, but just fatigued, and that can actually good. Your muscles and body need to be fatigued in order to improve, developing muscular strength and endurance.

When I first began tri training a few years ago I felt worn out after a day with two hours of exercise, but now that's pretty routine for me. It's part of the process of building a good endurance base, and with it will come speed. You also need to build in recovery weeks to your training. The general principle is three build weeks, followed by a rest week, then three more build weeks, and so on. In your rest/recovery week you should back off on volume (say 60% of the previous week), but still have high intensity during your workouts.

Now, if you are feeling very lethargic, have a hard time getting out of bed, feel sick - that's a different thing.

If you have to ask if you're overtraining, you aren't.

You should feel it when you are.

Everything is a balance...it's not just about training.

As Chris mentioned, most "recreational" athletes cannot train enough to actually "overtrain".  But since most recreational athletes also have a full time job, family, and other obligations...it becomes possible that their training is not balanced with enough sleep, rest, and recovery.

If my training consists of 30 minutes of jogging everyday, it's pretty impossible to say that I'm overtraining...right?  But if I'm balancing that with only 2 hours of sleep every night, and 10 hours of manual labor work, kids, etc...then that 30 minute jog is probably going to feel like crap.

Find your balance.  Your body is likely capable of training 30+ hours a week...but you have to balance it for that to work.  Most people can't afford that balance though.

It is common for those that are new to the sport to put in "extra" training in addition to what they should be doing according to their training plan.  This of course depends a lot on what they are training for and what sort of plan they are following...but in general...

I think this can result in "over training". This term has a broad interpretation, but meaning that it can exceed the fitness they are are currently at. As a result, not recovering properly, at risk for injury, and other performance problems.

I know, because I did it my first year. I was so into getting out there and training that I didn't have a sense of when to stop and rest. Now I'm much more careful, but I do see those new to the sport doing the same thing.

When you train muscle cells are damaged and broken down, your body responds by building new and more muscle fibres to make you stronger. This of course assumes enough time for restitution and adequate nutrition. Overtraining is when your body is not able to rebuild the muscle fibers, this is result of a combination of lack of rest, inadequate nutrition and excessive exercise over a prolonged period of time. 

For the normally healthy person, amateur athlete with a healthy and varied diet, overtraining is unlikely to occur, but if you're on a weight loss program you may become overtrained. A reduced diet may result in lack of sufficient key nutrients even if you get enough protein. In fact loss of muscle mass is a common problem with many weight loss programs.

More common, when you train hard, your glucose deposits are depleted, this should not be confused with overtraining and it's common to have periods where you feel burned out. It takes some time to refill and a low carb diet may slow recovery. You may also dehydrate but not feel thirst, glucose storage requires 4 times as much water, that is to store 100g of sugar in your muscles you need 400g of water. An extra day rest, and eating healthy carbs you will recover fast. 

BR, Erik

Possibly, and probably a good idea anyway. (Are you eating enough calories, period? Are you trying to lose weight, by any chance?)

To be clear, if you are in true glycogen depletion, you're not merely fatigued. You're at the point where you simply will not be able to do the next workout.

Also, a gram of glycogen (the form glucose is stored in) is stored in muscle with 2.7g of water by weight. (Not to be confused with storage ratio by molecule). However, the take-home message to stay adequately hydrated remains, especially if you're upping the carbs in your diet.