After far too long dithering, I finally started doing intervals. My excercise program for intervals is simple. 4 minutes warm up, 10 loops arond a hysterisis with a high point of 180 beats per minute, and a low point of 140 beats per minute, and then 4 minutes cool down.
I was reminded of why I don't like doing intervals. During the up phase, I'm running pretty fast, which means that a lot of the seawall is too dangerous. I also think the battery in the chest strap of my heart rate monitor needs to be replaced, as it had this nasty habit of not updating, right about when I should have been hitting 180bpm..