What would be the consequence of hemoglobin deficiency in our body?

Hemoglobin is a protein that carries oxygen throughout the body. The protein is found in red blood cells, and the amount of hemoglobin from person to person is variable. The amount of hemoglobin a person has is also variable from time to time as well. A low hemoglobin count could be an indicator for a much more serious condition like anemia; however, the question appears to be asking for general signs and symptoms of a low hemoglobin count. Because hemoglobin binds oxygen to it, a low hemoglobin count means that the body isn't getting the oxygen to the cells that it should be. The body compensates for the lower oxygen levels by increasing heartbeat and breathing rates. A person would feel short of breath all the time. Additional signs and symptoms would be general fatigue, weakness, and possible pale skin and/or gums.
https://www.mayoclinic.org/diseases-conditions/iron-deficiency-anemia/symptoms-causes/syc-20355034