What are the sleep characteristics associated with rising AM testosterone levels?
- There is accumulating evidence in adult men that the testosterone profile is significantly influenced by NREM–REM cycling.
- Sleep architecture, characteristics which is associated with a nocturnal rise in am testosterone, as follows: (1) duration of the first NREM period; (2) daytime recovery sleep; (3) habitual sleep duration.
- Restriction of sleep to 5 hours/night for just 5 consecutive nights decreases am serum testosterone levels up to 15% and one night with no sleep or sleeping only 4.5 hours in the first half of the night decreases am testosterone levels by 20%.
- These facts argue for assessing sleep habits of patients in the workup for hypogonadism (see last question of the chapter on taking sleep history).
