A Finnish study involving 2,570 middle-aged men (42-60) has found that men sleeping less than 6 hours or more than 10 hours suffer from low-grade inflammation (indicated by levels of C-reactive protein) more often than persons sleeping 7-8 hours per night. Additionally, the serum levels of zinc, and the zinc/copper ration, were lowest in those sleeping less than 6 hours, while copper levels were highest in those sleeping more than 10 hours.
It has been suggested that high serum copper concentration is linked to pro-oxidative stress, found in many chronic diseases.
Luojus, M. K., Lehto, S. M., Tolmunen, T., Elomaa, A.-P., & Kauhanen, J. (2015). Serum copper, zinc and high-sensitivity C-reactive protein in short and long sleep duration in ageing men. Journal of Trace Elements in Medicine and Biology, 32, 177–182. http://doi.org/10.1016/j.jtemb.2015.07.008