Folks who are serious about
intense athletic endeavors can find themselves «over-trained»,
feeling lethargic and susceptible to every
cold the kids bring home.
Birkeland currents are interesting, although they seem to be a possible correction to direct solar irradiance only at the poles and only in the ionosphere, which is already enormously hot — between 1500C and 2500C — but so tenuous that you wouldn't
feel heat if you stuck your arm out into the near vacuum of the ionosphere, you'd
feel intense cooling as your blood started to boil and ordinary thermometers would radiate heat away faster than they would equilibrate (and hence would read very
cold temperatures).