Why is it not advisable to sleep in a closed room with shouldering fire in it?

During daytime plants have photosynthesis, which enables them to consume and convert atmospheric CO2 into O2, while during night reverse happens as photosythesis can not take place due to absence of sun light. Plants breathe in which CO2 is exhaled while O2 is consumed.

So, if someone sleeps in an enclosed room with plants, the level of CO2 may go beyond tolerable level of humans, which might eventually suffocate and kill humans. That is why we are adviced not to sleep in enclosed room full of plants.