Can obstructive sleep apnea lower testosterone in men?

Obstructive sleep apnea (OSA) is defined by recurrent upper-airway obstruction that fragments sleep and causes intermittent oxygen desaturation. In men, these exposures are linked to disruption of the normal sleep-dependent rise in testosterone.

Clinical evidence

• A systematic review/meta-analysis of 18 studies including 1,823 men found lower testosterone in those with OSA (standardized mean difference −0.76, 95% CI −1.18 to −0.33). The association persisted after adjustment for age and BMI and was most evident in severe OSA.
• In an intensive overnight polysomnography study with blood sampling every 20 minutes, men with OSA had substantially lower cumulative nocturnal testosterone exposure than controls (67.2 vs 113.3 nmol/L·h; P<0.003), demonstrating an attenuated overnight testosterone rise.

Mechanistic evidence

• Sustained sleep, particularly early sleep and REM-associated sleep, normally supports nocturnal hypothalamic–pituitary–gonadal activity. Recurrent arousals appear especially important: sleep fragmentation had the strongest relationship with reduced overnight testosterone secretion.
• Nocturnal luteinizing-hormone exposure was also reduced in men with OSA, consistent with impaired GnRH/LH pulsatility as an intermediate pathway. Intermittent hypoxemia may add to this effect, potentially through altered LH pulsatility and testicular steroidogenesis, although its independent contribution is less certain than that of fragmentation.

Interpretation and clinical context

• Obesity is a major shared contributor: it increases OSA risk and independently lowers testosterone. Age, metabolic illness, medications, sleep duration, and SHBG can also influence measured testosterone. Indeed, in MAILES, the AHI–testosterone association disappeared after adjustment for age, BMI, and SHBG.
• CPAP has not consistently increased testosterone or gonadotropins, indicating that correcting airway obstruction alone may not fully reverse endocrine effects.

Bottom line

• The claim is supported: in men, OSA-related sleep fragmentation and intermittent hypoxia are associated with lower testosterone and can blunt the normal nocturnal testosterone rise, particularly in more severe OSA. Sleep fragmentation has the clearest mechanistic signal; obesity and related metabolic factors substantially shape the observed association.