Unlocking Better Sleep: The Impact of Lowering Insulin Levels
When struggling with sleep, most people focus on bedtime routines, relaxation techniques, and sleep environment. But one of the most overlooked factors is insulin. Insulin resistance can interfere with your body’s natural sleep-wake cycle, making it harder to fall asleep, stay asleep, and wake up feeling refreshed.
Understanding how insulin affects melatonin and cortisol—the two key hormones that regulate sleep—can help you take control of your sleep quality and overall health.
How Insulin Affects Sleep
Insulin is best known for its role in blood sugar regulation, but it also plays a direct role in sleep. When insulin is released, it helps transport amino acids, including tryptophan, into the brain. Tryptophan is a building block for serotonin and melatonin, both of which are essential for regulating sleep. But the relationship between insulin and sleep becomes more complicated in people with insulin resistance.
Insulin and Melatonin: Separate Cycles, Opposing Roles
Insulin and melatonin operate on separate biological cycles. During the day, insulin rises in response to food intake, helping to regulate blood sugar and energy storage. At night, when the body is preparing for sleep, melatonin levels rise while insulin naturally decreases.
This separation exists for a reason. Melatonin signals the body that it is time to rest and repair, while insulin is primarily a daytime hormone that helps process food. The two should not be elevated at the same time. Normally, while you sleep, insulin levels remain low because you are not eating, allowing the body to shift into a fasting state where it burns stored energy, repairs cells, and regulates metabolic processes.
How Insulin Resistance Disrupts the Sleep Cycle
In people with insulin resistance, insulin levels often remain high even when no food is being consumed. This disrupts the natural cycle and can interfere with melatonin production, making it harder to fall asleep and stay asleep. Since 9 out of 10 US adults have insulin levels that are too high, this explains why sleep issues are common.
Melatonin Suppression
When insulin levels are too high at night, melatonin production is suppressed. Since melatonin is responsible for regulating the sleep-wake cycle, this can lead to:
- Difficulty falling asleep
- Lighter, less restorative sleep
- Frequent nighttime wake-ups
This is one of the reasons why eating late at night can interfere with sleep—food triggers an insulin response when melatonin should be taking over.
Cortisol and Nighttime Alertness
Elevated insulin levels can also contribute to higher cortisol production, which keeps the body in a more alert state. Cortisol and melatonin work in opposition—when one is high, the other should be low. But when insulin resistance keeps insulin and cortisol elevated, melatonin production is delayed, making it harder to wind down.
This leads to the frustrating experience of being tired but wired—feeling exhausted all day but unable to fall asleep at night.
How to Lower Insulin and Improve Sleep
If high insulin levels are disrupting your sleep, the best approach is to lower insulin naturally through lifestyle changes. Here are the most effective ways to do that:
1. Eat to Keep Insulin Low
What you eat plays a major role in insulin levels. Avoiding insulin-spiking foods can help regulate melatonin and cortisol production.
- Focus on non-starchy vegetables, healthy fats, and lean proteins
- Avoid starchy foods like grains, beans, and potatoes
- Limit milk and whey protein, as they are highly insulinogenic
- Cut out sugar and refined carbs
2. Prioritize Movement
Exercise improves insulin sensitivity and reduces cortisol levels, making it easier to fall and stay asleep. Even a 10-minute walk after dinner can help stabilize insulin and set you up for better rest. Other effective forms of movement include:
- Strength training
- Yoga
- HIIT (high-intensity interval training)
- Low-impact cardio like walking or cycling
3. Manage Stress Before Bed
Since stress and insulin resistance go hand in hand, managing cortisol levels before bed is key. Simple ways to lower stress include:
- Deep breathing exercises
- Meditation or journaling
- Listening to calming music
- Taking a warm bath
- Avoiding blue light from screens at least an hour before bed
The Bottom Line
If you are struggling with sleep, insulin resistance could be playing a role. High insulin levels can interfere with melatonin production and increase cortisol, making it harder to fall asleep and stay asleep.
By following A Low Insulin Lifestyle—focusing on insulin-friendly foods, regular movement, and stress management—you can naturally regulate your sleep hormones and wake up feeling more refreshed.
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