Circadecennian peak expiratory flow and the putative merit of self-measurement

Peak expiratory flow (PEF) can be self-measured. Self-measurements of PEF on a long-term basis permit assessment of the time structure of PEF and its relation to solar activity expressed in Wolf's relative sunspot number. The results from a longitudinal record spanning 32.5 years were compared with four other shorter series. It appeared that the most prominent periodicity in the annual and infra-annual response of the spectrum was a component with a period of 11.74 years. This periodicity was comparable with the periodicity found for Wolf's relative sunspot number (10.27) during the same span of time.