Does the effective use of CPAP in OSA lead to weight loss?
Results are not consistent on this matter. Some 30% of patients treated for OSA may have stable or even increased body weight, with two mechanisms having been implicated: (1) Decreased work of breathing with treated OSA translates to conservation of calories during sleep; and (2) improved sleep architecture leads to increased SWS and, therefore, increased GH secretion with attendant weight gain. For those that lose weight, two distinct mechanisms have also been proposed. First, patients treated for OSA usually wake more rested and with a sense of improved vitality or energy; once on treatment, patients with OSA have even been shown to exercise more. Second, treatment of OSA results in normalization of serum leptin (from the Greek word leptos , meaning “thin”), the so-called satiety hormone. As will be discussed below, leptin is suppressed during sleep deprivation and in untreated sleep apnea.