Hi, so I have been running base miles for the past 6 weeks or so. I ran a 20:55 5k in the fall for my XC season and this is my first time running a consistent base. However, everyone was telling me that I could have run so much faster in the XC season if I slowed down on my easy runs, which I ran around 8:45 in season. So, I slowed down A LOT during my base miles. I seriously went from around 8 mins/miles(in season) to 13 mins/mile and I am around 11 per mile now. Keep in mind I have not been doing any strides or speedwork, just long, relatively easy miles and a long run that is 20% of my weekly mileage. I have been trying to MAF train, which puts my ceiling at 164 BPM, give or take. I have been pretty successful with slowly speeding up those easy miles and keeping my HR low. However, I decided to start throwing in a tempo once a week and today, I went to start that first tempo run and I found I had trouble even going at a 7:50 pace for two miles. I thought that my aerobic ability would be next level, and I might be able to pull out some wicked times compared to XC season but I couldn't even stay in the seven minute mile range and I had to quit at 1.91 miles. Obviously this upset me, a lot. I want to be at least in the high 18's or mid 19's for the 5k by outdoor track season and this is a huge setback. I did some research and lots of sites say that if you don't work on speed, you will lose speed. Obviously. I think it's worth noting that in this "tempo run", my peak HR was 155 BPM, my average pace was 7:51 and the distance I ran was 1.91 miles. My HR was relatively low, it's just my breathing that felt horrible! I understand tempo runs aren't supposed to be that hard, (I kind of threw out the "comfortably hard" rule and just ran at full effort), but it just blew me away that I couldn't even go sub 7 at full effort! I really just thought my aerobic capability would be on the next level at this point since I bumped up my mileage higher than it's ever been. I am worried that I slowed down too much for too many consecutive runs and now my fitness level is messed up. Or maybe it's not. I don't know, it's just confusing and mentally depleting. But in this run, my heart rate was at an aerobic level ( at least for the 1.91 miles I completed), but my breathing felt HORRIBLE. I though base training at a slow effort was supposed to make breathing at a faster effort eaier? Hence the reason I am running at "aerobic HR?" My question is, 1, where the heck did my speed go? I was able to run a 6:45 mile average during the 5k and a PB of 6:08 in the mile once the season was over a couple months ago. Why is it that I have lost so much speed in 6-8 weeks? And 2, how do I get that speed back? It's not like I just stopped running. I have ran almost every day since the season ended, except for one off day a week. I am at the crossroads in base training where I am going to add some hills, fartleks, and intervals in to get my legs quick and snappy for the track season but if I can't even run under 7:30 mile pace for TWO MILES, how am I even remotely ready to start training for the goals I want in track season? It's just frustrating. Any advice, tips, or meaning would help so much!!!