X-ray activity cycles consistent with the X-ray measurements of LHS 1140 and the He observations of LHS 1140b. Measured X-ray fluxes are plotted in black. The vertical green and red lines indicate the detection and nondetections of metastable He from LHS 1140b, respectively. Sine curves are plotted from a grid search of periods between 1 and 20 yr. The curves were filtered such that the X-ray flux at the time of the WINERED He nondetection on 2025 September 28 (red dashed line) must be 3× lower (panels (a) and (c)) or 10× lower (panels (b) and (d)) than that at the time of the He detection made on 2025 September 23 (green dashed line). This constraint was not enforced for the JWST nondetections (red dotted lines). The sine solutions were also filtered to pass through the measured X-ray points. A hypothetical X-ray measurement on 2026 December, during the next visible epoch with XMM-Newton, is shown as an open circle in panels (c) and (d). Panels (c) and (d) show cycles consistent with this measurement if it reveals an X-ray flux similar to the previous measurements.