We investigate the scaling of the core energy transport with the magnetic Lundquist number S in the reversed field pinch. We analyze for the first time the electron temperature and thermal conductivity profiles and the dynamo magnetic fluctuations in a wide range of stationary plasmas produced in the RFX device at plasma current ranging between 0.2 and 1.1 MA. When S increases we measure an improvement of core confinement associated with the strengthening of the internal electron temperature profiles gradient and with the decrease of magnetic turbulence. This shows that core energy transport is related with magnetic fluctuations and can be ameliorated in high S regimes. The role of self-generated internal electric currents is crucial to control the plasma dynamic evolution in the reversed field pinch (RFP), a magnetic configuration studied for the confinement of thermonuclear plasmas. These currents are driven by the continuous action of a magnetic field regeneration mechanism, often called “dynamo.” This mechanism can be powered by magnetic fluctuations due to a wide spectrum of m 1 resistive tearing modes [1,2], which are thought to be the cause of anomalous energy and particle transport in the RFP core. This makes a well diagnosed laboratory plasma like the RFP resemble geophysical and astrophysical systems. Moreover, it offers a unique experimental opportunity to study the role of resistive magnetohydrodynamics (MHD) magnetic fluctuations in driving anomalous energy transport in magnetized plasmas [3] and how this mechanism scales to more collisionless, reactor relevant conditions. The role of turbulence in controlling transport is in fact still the subject of active investigation, in particular, in the plasma core where measurements are difficult. According to MHD theory, the relevant dimensionless parameter to scale the amplitude of normalized magnetic fluctuations