Hello, I hope this is the right place to post this question. I recently bought a heart rate monitor to help with pacing, and I have a couple of specific questions. My heart rate lying in bed after I wake up (resting heart rate) seems to be right around 70, but sometimes during the day I notice it going down quite a bit lower than that (like mid 50s), especially when sitting on public transit and even when standing and waiting for the bus. Is this common? And this afternoon after lunch I took a nap, and noticed when I woke up (and was still in bed) that my heart rate was around 90. Is this from eating? Also, I am thinking of having exercise testing to determine my anaerobic threshold. The place I contacted (a sport facility) calls it "lactate testing", which I gather is basically the same thing. Is this the test that people with CFS do to help avoid post-exertional malaise? Are there any certain values that I should make sure the test includes?