Low heart rate and high perceived effort on easy runs - overtraining, glycogen deficient, or delayed muscle recovery?

It's a sign that your body is fatigued. Take it easy. Run shorter distance at recovery pace instead of trying to get to easy pace. You're doing high mileage, so it's not that surprising.

I get the same thing. When I'm not recovered from a race or big workout, I'll be 15 seconds/mile off my easy pace and my HR will be 5-10 bpm below typical easy pace heart rate, and I'll still feel awful. I try to make it through the run, cut it short if necessary, and make sure not to attempt another workout until my regular run is back on pace.

Thanks! Appreciate the reply. I think I'll push some workouts further out this week until my pace/HR levels get back to normal.

I suspect I need to be more careful with tracking my carb intake too - there's a good chance these low HR//low speed/high effort runs are linked to poor or improper refueling in the days after a long run or a hard workout.

Again - appreciate the reply.

I have not had that happen to me from running. I have never logged more than 60 miles in a week. I was very weak the last 2/3 of U.S.M.C. basic training, about 8 weeks. During basic training, my calories and food choices were restricted. I sucked it up and did not complain. Last week of basic training, Marines are supposed to donate blood. I was diagnosed anemic prior to giving blood. I was not allowed to donate blood. Get your iron level checked.

Good advice above.

Sleep, eat heaps, jog or rest.

I had the same in cycling. Would go on very long rides, and eventually I was unable to get my HR up. Felt like I had no power/energy. Could still sprint a bit tho with my FT fibers. Also was able to run normally, which is the important point.

What most likely happened to you is that you depleted your running-specific ST fibers in your legs. It will take several days to get the legs back up again. Imagine your brain putting a block on your system, not allowing you to run fast right now so it can recover. Otherwise, if the brain would just let you keep running and running even while the body is totally depleted and out of carbs and energy, you would die. So be happy for it, even if it sucks to run right now.

Go for walks or do some cross-training at low intensity, that should still be possible now using almost entirely fat as energy source.

sounds like glycogen depletion. Just take easy runs very easily and keep them short when you feel like that, and consider taking extra days easy and short too. Are you spacing out your harder days adequately? Is it very hot and humid where you're training? You might also consider adding in down weeks somewhat regularly if these unanticipated bad slow runs keep popping up AND your races aren't where they should be. Within four months of raising mileage you should be pretty adapted by now if you haven't been overcooking yourself. Mileage is just a number...

Thanks, everyone - some good advice here; a solid thread that shows the value of these boards.

Re: bill adcocks fan, I'm in New England, and, to be honest, have recently been struggling with the heat and humidity (this is my first summer training in the high 20s early 30s with high humidity). I think you're right to suspect this may have played a role. I'm also a heavier/power-based runner with a have a high sweat rate, so I might be asking for too much for my training for this time of year.

I'm currently using a 3 week long/hard, 1-week easy/shorter cycle, but maybe I should think about lowering this ratio to 2-1 for a while, or cycling between 3-1 and 2-1. I following an adapted Magness marathon program, although am not aiming to hit the peak mileage (120-130mpw) in this training block.

Again - thanks for the comments.