  Long-term photometric measurements in a sample of ultrashort-period (P~0.5
days or less) single and binary stars of different interior structures are
analysed. A loose correlation exists between the rotational rate and cycle
lengths of active stars, regardless of their evolutionary state and the
corresponding physical parameters. The shortest cycles are expected on the
fastest rotators in the order of 1-2 years, which is reported in this paper.
