I want you to ask yourself how many days off you take each week. And when I say off I mean off. Not “I do an hour of aerobics but that doesn’t count.” I mean off. One, maybe two. Probably not that many. How many people (the ones wearing the various braces) are in there every day, sometimes more than once? Either they are doing weights multiple times per week and cardio on the off days or they are doing both each day.
Trust me, I’ve been there too, trying to train 6 days/week (I at least conceded one day off per week, although I didn’t do that consistently until my late 20’s) and wondering why I was burnt out, tired all the time, not performing well, etc.
Most runners run 6 days/week. Yeah, and most runners are overtrained and chronically injured. And Arnold and his ilk lifted 6 days/week. Genetics and drugs. Same with the Bulgarians, the Soviets, you name it. These are the genetic elite, training full time with no job or life stress, and juiced to the gills. Unless you have all those things going for you, you shouldn’t try to emulate their training. And given that a massive percentage of elite athletes report being overtrained, perhaps even they should be training less frequently.
Which is simply a long winded way of suggesting that, if you are anything like the normal trainee, you’re doing too much. You probably train too many days per week and take too few days off. You’re lifting 3-4 days/week and trying to do cardio another 3-4 days/week (this is especially true if you are a fat/weight obsessed female). And you wonder why your joints are always kind of sore, you don’t really look forwards to your workouts anymore and everything that signals, if not true overtraining, at l
east overreaching (the 
distinction is another topic 
for another day).
So, I want you to look at your current training schedule, how many days are you training, how many days do you have off? I recommend that everyone, and this is true from the beginning exerciser to the elite athlete have at least one day completely off from training. That’s the minimum.
This is called passive rest, I want you to sit around all day. I’m not a religious person but this is best summed up by a quote from Charlie Francis’s book Speed Trap. Francis had asked his coach if they could afford to take Sunday’s off. His coach told him “The Lord made the world in six days, and on the seventh he rested. Do you think you could do better than that?” Most elite athletes take at least one day off from training each week and the ones who don’t usually pay for it in the long run. Why do you think you need more training than they do? If you simply can’t stay still and not do something, go for a brisk walk outdoors. But stay out of the gym. See if you aren’t refreshed when you go back to the gym the next day.
Even for general fitness exercisers, I think taking extra days off (or performing active rest) is beneficial. Find places to cut your weight training down (most people’s workouts are absurdly long) and put some of your cardiovascular work after your weights (on upper body days). I think you get the idea. Find a way to get your training down to 3-4 days/week total with 1 day completely off and a couple of days of active recovery.
Until tomorrow: Time stays long enough for anyone who will use it.