Sleepless and Storing Fat: How Chronic Insomnia Alters Metabolism

Struggling to get through the day after a sleepless night is something most of us have experienced. But what if those nights start piling up — week after week, month after month? Chronic insomnia doesn’t just leave you groggy and irritable; it may also be quietly rewiring your metabolism and encouraging your body to store fat.

Insomnia is one of the most common sleep disorders worldwide, with around 10% of adults experiencing it chronically.¹ It's defined by difficulty falling asleep, staying asleep, or waking too early — happening at least three times a week for over three months, and interfering with daytime functioning.¹ While we often think of sleep as a luxury, research increasingly shows it’s a metabolic necessity.

When we sleep, our body enters a finely tuned hormonal rhythm. Two of the key players in this cycle are ghrelin and leptin — hormones that regulate hunger and satiety. Ghrelin, secreted by the stomach, increases appetite, while leptin, produced by fat cells, signals fullness and regulates energy balance.² Chronic sleep deprivation throws this balance off-kilter. Studies have found that even a couple of nights of poor sleep can raise ghrelin levels and decrease leptin, leading to increased hunger and higher calorie consumption the next day — often without increased energy expenditure.³

That means your body is tricked into feeling hungrier, while simultaneously becoming more inclined to store fat. Over time, this hormonal misfire can pave the way for weight gain, especially around the abdomen — a hallmark of metabolic syndrome, which includes high blood pressure, insulin resistance, and elevated blood lipids.⁴

Insomnia is also linked to increased activity of the sympathetic nervous system (your fight-or-flight response), elevated cortisol levels, systemic inflammation, and disrupted insulin regulation.⁴ These stress-related responses impair glucose metabolism and fat breakdown, further increasing your risk of obesity, type 2 diabetes, and cardiovascular disease. In fact, research shows people with chronic insomnia are up to 1.4 times more likely to develop conditions linked to metabolic syndrome compared to those who sleep well.¹

And it’s not just how long you sleep — quality matters too. Fragmented or shallow sleep can impair metabolic functions even if total sleep time seems adequate.² Add in the fatigue and low energy that comes from poor sleep, and it’s easy to see how reduced physical activity becomes part of the equation, further compounding weight gain and metabolic risk.²

In short, if you’re finding it hard to shift stubborn weight, it might not just be your diet or willpower — your sleep could be working against you.

If you regularly struggle to fall or stay asleep and feel the effects during the day, speak to your doctor. Addressing insomnia might not only help you feel more rested — it could be the key to protecting your long-term metabolic and cardiovascular health.

How Sove CPAP Clinic Can Help

Founded in 2008, Sove CPAP Clinic has grown to become a leading provider of respiratory and sleep services and products in Australia, with over 60 clinics nationwide. Our comprehensive clinical team includes Respiratory & Sleep Specialists, Sleep Technologists, and CPAP Consultants, ensuring that you receive comprehensive and personalised care. All medical procedures, including sleep studies and lung function testing, are bulk billed to all Australians, with minimal wait time.

If you would like to speak to a Respiratory & Sleep Physician, book a bulk-billed sleep study, or seek advice for your sleep apnea, you can reach us at 1300 76 29 39 or info@thecpapclinic.com.au.

ALWAYS FOLLOW THE DIRECTIONS FOR USE. CPAP is used for Obstructive Sleep Apnea treatment. When considering whether a sleep study or CPAP is right for you, speak to your doctor. Medicare criteria and T&Cs apply.

References

1. Zhang, Yuanfeng, et al. “The Association between Insomnia and the Risk of Metabolic Syndrome: A Systematic Review and Meta-Analysis.” Journal of Clinical Neuroscience, vol. 89, July 2021, pp. 430–436. https://doi.org/10.1016/j.jocn.2021.05.039
2. Pacheco, Danielle, and Abhinav Singh. “How a Lack of Sleep May Increase Calorie Consumption.” Sleep Foundation, 11 Dec. 2020. www.sleepfoundation.org/sleep-deprivation/lack-sleep-may-increase-calorie-consumption
3. Schmid, Sebastian M., et al. “A Single Night of Sleep Deprivation Increases Ghrelin Levels and Feelings of Hunger in Normal-Weight Healthy Men.” Journal of Sleep Research, vol. 17, no. 3, Sept. 2008, pp. 331–334. https://doi.org/10.1111/j.1365-2869.2008.00662.x
4. Zou, Ding, et al. “Insomnia Is Associated with Metabolic Syndrome in a Middle-Aged Population: The SCAPIS Pilot Cohort.” European Journal of Preventive Cardiology, vol. 28, no. 8, 21 July 2020, pp. e26–e28. https://doi.org/10.1177/2047487320940862