I have been exercising that includes cardio and weight
training in a gym resulting in 10-kg weight
loss, but lately I have noticed that while lifting weights, although, I exhale, as instructed by the gym instructors, I develop bluish discoloration of my lips, which disappears after bringing the weight down to the relax position. I wonder what is wrong with me and I feel I sweat a lot while doing cardio also. Could you guide me as to why this happens.