The spontaneous current increase of field emission in a subexplosive state is investigated theoretically as well as experimentally for smooth and reconstructed cathode tip. The evaluation based on the thermal conductivity equation with Nottingham effect shows that for some conditions the tip of the reconstructed emitter may be heated to a lower temperature compared to smooth one. As a result the stable emission current for a reconstructed tip can grow significantly. An experimental approbation showed that the value of the emission current doubles for this case.