Short sleep raises ghrelin, dulls insulin sensitivity and steers appetite towards sugar. Untreated sleep apnoea makes the whole loop considerably worse.
Sleep is not a passive gap in the day. Restricting it to five hours raises ghrelin, the hormone that signals hunger, and lowers leptin, which signals fullness, so appetite rises while the sense of having eaten enough falls away. The appetite that rises is specifically for dense, sweet, easy food. Several short nights in a row also measurably reduce insulin sensitivity in otherwise healthy people. Diet adherence does not collapse because of weak character; it collapses at four in the afternoon.
Fat around the neck and pharynx narrows the airway, and during sleep the muscles relax enough for it to close. Oxygen falls, the brain briefly wakes to reopen the airway, and the sequence repeats dozens of times an hour without the person remembering any of it. The result is daytime exhaustion, less physical activity, worse glucose control and more weight, which narrows the airway further. Loud snoring, witnessed pauses, morning headache and dozing off while driving are the signals.
Untreated apnoea changes the risk profile of an operation. It affects airway management at induction, sensitivity to opioid painkillers and the likelihood of low oxygen levels on the first night after surgery. Every bariatric patient here is screened with a questionnaire, a neck measurement and oxygen saturation, and this is one of the reasons the surgery happens in a hospital with intensive care rather than a day clinic. Bring your machine if you already use one.
Weight loss after a sleeve improves apnoea substantially in most patients over six to twelve months, and a proportion no longer need positive airway pressure at all. The mistake is deciding that for yourself. The device is stopped after a repeat sleep study confirms it, not because month four feels easier, and stopping early puts you straight back into the loop the surgery has just broken. Ask your own sleep physician to repeat the study at around one year.
Seven to nine hours for most adults, and consistent timing matters nearly as much as duration. A regular bedtime does more for appetite control than any supplement sold for the purpose.
Yes, and it is safer than being operated on with undiagnosed apnoea. Bring the machine and its settings so the anaesthetic team can plan around them.