“After 1 week of 8-hour bedtimes (from 11 PM to 7 AM) at home, the participants spent 11 days in the laboratory for 3 nights of 10-hour bedtimes (from 10 PM to 8 AM; rested condition) followed by 8 nights of 5-hour bedtimes (from 12:30 AM to 5:30 AM; sleep restriction).”
After measuring Testosterone levels in these guys, the study goes on to say: “Daytime testosterone levels were decreased by 10% to 15% in this small convenience sample of young healthy men who underwent 1 week of sleep restriction to 5 hours per night, a condition experienced by at least 15% of the US working population. By comparison, normal aging is associated with a decrease of testosterone levels by 1% to 2% per year.”
This means that if you are a guy in his 40’s to 50’s and you’re working your ass off, stressed to the gills, and sleeping 4-5 hours per night- you have a big problem. So before anything else, start figuring out how to get 7-8 hours per night at least 5 times per week. You might assume that you can bump your Low T levels up naturally by doing this.
Want the study reference?
JAMA. 2011;305(21):2173-2174. doi:10.1001/jama.2011.710.