This is the most frustrating thing to research. I go to sites that discuss the different types of personal heart rate monitors, and they only mention two types. I was about to buy when I realized there are many more types. But no review sites mention this. I think the problem is these review sites are thinking only of people who do things like running. They are not thinking about sick people who do low impact activities. But here's what I found so far. 1. Chest strap (with reader in wrist or other places). 2. Touch device, where it takes your pulse when you touch it it. 3. Continuous display strapless wrist device. You wear it on your wrist and it continuously shows your heart rate. 4. Then there are these ones you wear on your upper arm, but I have not read how they work. 5. Next, there is one you slip onto your finger tip. This can cable to a wrist display, or the display can be on the device itself. These can also measure the amount of oxygen in our blood. I wonder if the O2 level reading would help use understand when we are in anaerobic respiration. Any thoughts on this??? 6. Finger strap. This looks like a tiny wrist watch, except the band goes around your finger. You just have to be careful not to give someone the finger when you show them your heart rate, although I guess the choice would be yours. Anyway, I'm sure these have their pros and cons, but review sites don't deal with this. Anyone know of a place that covers the whole topic? Any other thoughts?