135bpm too slow

I downloaded some remixes from Fitpod , they are 1hr long mixes at a set bpm. Last night I loaded up the 130bpm and 135 bpm to see how they would go. Started out on a 5k at 130bpm and it was way too slow so quickly changed to the 135bpm which was still very slow but my mp3 player didn't have enough room to load on anymore. 5k became 4k because time was running out and at 135pbm my average pace was about 7:20min/k. The slow run was probably good for the niggles but I was dissapointed with only doing 4k, should be good for 20k+ LSD though.
Next time I believe I will go for the 150+bpm, or slowly build up the bpm so I know how fast I go at each bpm and can use them to pace myself (which was the idea in the first place) anyway I have downloaded all the mixes from the site now and will be trialling them over the coming week.