Instruct: Classify a given review into positive or negative sentiment.
Query: Could not get a reading - doesn't fit the purpose

I tried the watch on both wrists, on both sides of the wrists, with all sorts of different fingers and positions and pressure and I could not get a reading. Every once in awhile when I am completely stationary I can get a reading after 10 seconds, but it's impossible to get a reading when I am actually exercising, which is the whole point.