In 1942, Soviet leader Joseph Stalin became aware of Chizhevsky's research work, including "Physical Factors Of The Historical Process", and Chizhevsky was asked to retract his writings on solar cycles, which contradicted Soviet theories of the reasons for the Russian revolutions of 1905 and 1917. He refused, was arrested and spent eight years in a forced labor gulag in the Ural mountains. He was released in 1950 and resettled in Karaganda in Kazakhstan where he underwent eight years of Soviet "rehabilitation" where he conducted science work in coal mines of Karaganda. While he no longer wrote on solar cycle theory, he returned to Moscow and introduced aero-ionic therapy (similar to negative air ionization therapy) into some medical establishments. He became a scientific consultant and ran an aero-ionification laboratory under the USSR State Planning Organisation.