OK, so here's the thing.
I'm a high mileage runner and advocate. I respond best to high loads of training and have been running about 90-100 miles/week on average for the past 6 months since my comeback. Of course, I go through mini-tapers ( 4-5 days) before a scheduled race ( ranging from the 1500m to the half-marathon) but overall, I've been pretty consistent since January with the training.
During the week, I also incorporate about 2-3 track workouts and a tempo run ( distance and pace varies depending on the purpose of the workout). I make sure to run the bulk of my miles at an easy pace ( 8:00/mile) to ensure recovery from the speed workouts. So either I'm running really fast ( structured workouts, under 6:00/mile) or really slow ( my long runs over 15 miles are also at 8:00 pace but I'm not training for a marathon anyway)
I have found that high mileage gives me great endurance and it transfers over to my V02 max workouts. It also helps me keep my weight down, since I'm not one of those runners blessed with a super slim body and a blazing metabolism. On top of that, my long runs are what I enjoy the most about the sport.
That being said, however, I'm concerned that I've gone over the deep end or that the program I'm currently on is not sustainable for such an extended period of time. Recently, I've noticed that all I want to do is sleep. I'm drained of all my energy. I get through workouts almost as if they were races. And I'm beginning to wonder if maybe the runs at 8:00 pace are compromising my speed, as if the legs and muscle fibers are being "locked" into a slow twitch state. But at the same time, I've read so much on the importance of recovery that I'm afraid to hammer all my runs, even on easy days.
Another factor has been my lifetyle/work schedule. I'm a teacher, but I'm only getting 4-5 hours of sleep a night because I do most of my training at 6pm ( not a morning runner and I live in Miami where it's super hot) and need to be up the next day by 5am. I'm also very unhappy at my job which might be contributing to this lethargy. On the weekends, I'm a completely different runner, only because I can sleep in and get the rest my body needs. But I can't just be a bum and train full-time.
I have very modest times, but I know I can improve. My PR's are as follows:
1500: 4:19
3000: 9:25
5000: 16:20
8000: 27:02
Half-marathon: 1:16:17
I'm all too aware that if you don't train smart, there's no way to optimize your potential. I might as well be running myself into the ground.
Any advice?