A GP has outlined five surprising ways that significant weight loss from injections such as Wegovy and Mounjaro can affect sleep, including waking with new hip pain or finding a mattress too firm. Research shows the number of adults using GLP-1 medications in Great Britain has nearly tripled over two years to 1.9 million, with 68% now taking them primarily for weight loss.
As use of weight-loss medications rises, health experts are cautioning about potential issues. Dr Roger Henderson, GP and medical expert for MattressNextDay, warns that an unanticipated effect of significant weight loss is its impact on sleep. The consequences can go beyond mere discomfort, he explains, as struggling to settle, shifting position, or waking due to new aches can interfere with sleep.
Those taking GLP-1 medications may also face sleep-related difficulties. The medical specialist cautions that side effects such as nausea, indigestion, acid reflux, and abdominal discomfort can make it harder to get comfortable at night.
Nausea and acid reflux may disrupt sleep
For some individuals, changes in sleep patterns can emerge before substantial weight loss occurs. Dr Henderson elaborates: "Some people do notice changes to their sleep after starting weight-loss medication, but this is usually due to its side effects."
"Feeling nauseous, experiencing indigestion or acid reflux, or having some abdominal discomfort can all make it harder to get comfortable at night, particularly in the first few weeks after starting this type of treatment. Changes in appetite and eating patterns can also have an impact on sleep while the body starts to adjust."
These symptoms can make it more challenging to settle at bedtime or find a comfortable position. Reclining with a full or sluggish stomach can provoke nighttime nausea, acid reflux, or bloating, hindering the ability to drift off or remain asleep. Such injections can slow the rate at which food exits the stomach, prolonging the sensation of fullness.
Feeling colder and changing sleep positions
Dr Henderson advises steering clear of substantial meals near bedtime and maintaining a consistent sleep schedule while the body adapts. Should nausea, reflux, or other adverse effects prove persistent or worrying, consult the medical professional overseeing treatment rather than merely tolerating disrupted sleep. "The good news is that, for many people, these symptoms will settle with time," he concludes.
Individuals who have shed considerable weight may feel colder at night, as body fat acts as insulation. Dr Henderson says: "Some people can notice they feel colder at night than they used to after losing a significant amount of weight. These changes are typically nothing to worry about at all, but they can mean it takes a little time to get used to sleeping at a much lighter body weight." Feeling chilly can make it harder to settle comfortably or lead to waking during the night, even if the bedroom temperature is unchanged.
Substantial weight loss can also alter how weight is distributed across the body, making certain sleeping positions feel different. Dr Henderson says: "Losing weight, especially if it is a significant amount, changes how your body is supported while you sleep, so it can affect both your posture and your comfort." Reduced weight can ease strain on the hips, knees, and lower back, making movement easier and reducing joint discomfort. At the same time, less padding over bony areas can increase tenderness around the shoulders or hips.
Snoring and mattress changes
Weight loss can reduce pressure on the airways, helping to reduce snoring and improve sleep apnoea symptoms. Dr Henderson explains: "Weight loss can have a real impact on sleep, and it's usually for the better." However, he advises not to stop any treatment without medical advice. "If you're still snoring heavily, waking up gasping for breath or feeling exhausted during the day, it's important to speak to your GP," he adds.
Finally, the same mattress can feel completely different after significant weight loss. Dr Henderson explains: "Mattresses support us based on our body weight and shape, so if you've lost a significant amount of weight, the way your body lies on the mattress changes too." It's common for people to say a mattress they used to find comfortable suddenly feels much firmer, or that they become aware of pressure points they never noticed before. Following weight loss, there's also less natural cushioning over some areas, so tenderness or discomfort may appear. If that discomfort causes repeated position changes, struggling to settle, or waking during the night, it can start interfering with sleep quality.
