This creates a more humid situation. This, in addition to regular misting and the use of humidifiers helps add moisture to the air surrounding your plants. This eventually causes leaf drop. Underwatering also does damage to the plant. When the plant doesn't get enough water, the soil packs densely around the roots and subsequent watering often washes through the pot without finding the roots.
Most house plants like to be kept consistently moist.
If the plant lacks nitrogen, it's growth rate will slow and leaves will turn yellow and drop. If it lacks potassium, the leaves will burn at the tips and the plant will defoliate from the base upwards. If room temps are outside this range and the plant can't adjust, it will defoliate. The spots usually are white, brown or black with yellow margins. Often, the plant is been weakened and made vulnerable to infection by too much water or inadequate light.