If you’re over 40 and feel like you’re doing everything “right” but still waking up tired, stressed, and frustrated with stubborn blood sugar, this isn’t a discipline problem. It’s a physiological problem.
Today, we’re going to walk through four powerful, complementary strategies that work together to lower blood sugar, reduce cortisol, and improve sleep quality, without extreme dieting, longer fasts, or cutting more carbs.
This approach focuses on restoring balance in the systems that quietly drive insulin resistance and poor sleep, especially as we age.
Why Insulin Resistance Is Also a Stress and Sleep Problem
Most people are taught to think of insulin resistance as a food issue. But biologically, it’s also deeply tied to stress hormones and circadian rhythm.
When cortisol (your primary stress hormone) stays elevated into the evening and overnight, it directly worsens blood sugar control in several ways.
First, cortisol signals the liver to release more glucose into the bloodstream, especially overnight.
Second, it interferes with insulin signaling at the cellular level, making it harder for cells to absorb glucose efficiently.
Third, it fragments deep sleep, the exact stage of sleep where insulin sensitivity normally improves.
This creates a frustrating feedback loop: poor sleep raises cortisol, elevated cortisol drives higher blood sugar, higher blood sugar worsens insulin resistance, and worsening insulin resistance further disrupts sleep.
This isn’t a motivation issue. It’s biology, and biology can be corrected.
Magnesium: A Foundational Mineral for Insulin Sensitivity and Sleep
Magnesium is involved in over 300 enzymatic reactions in the body, including many that directly affect blood sugar and sleep. It plays a critical role in insulin receptor activation, glucose transport into cells, nervous system regulation, muscle relaxation, and sleep architecture.
Magnesium deficiency is extremely common, especially in people under chronic stress, those with poor sleep, and individuals with elevated blood sugar. In people with type 2 diabetes, magnesium is also lost more rapidly through urine, creating a vicious cycle where low magnesium worsens insulin resistance, which then accelerates further magnesium loss.
Large population studies consistently show that lower magnesium intake is associated with higher insulin resistance and a greater risk of developing type 2 diabetes. In fact, when researchers followed hundreds of thousands of people over time, they found a clear dose–response relationship: higher magnesium intake was associated with progressively lower diabetes risk [1].
Randomized clinical trials confirm this. When people are given magnesium, researchers see improvements in fasting glucose, fasting insulin, and HOMA-IR, a key marker of insulin resistance [2].
Mechanistically, magnesium is required for insulin to properly activate its receptor. Think of insulin as a key; magnesium helps that key turn smoothly. When magnesium is low, insulin has a harder time unlocking the cell, leaving glucose stuck in the bloodstream.
Magnesium also acts as a natural nervous system stabilizer. It supports GABA, the brain’s primary calming neurotransmitter, which helps lower nighttime cortisol, reduce liver glucose output, and promote deeper sleep.
Why Magnesium Glycinate Matters
Not all magnesium forms support sleep equally. Magnesium glycinate, magnesium bound to the calming amino acid glycine, is highly absorbable, gentle on digestion, and particularly effective for nervous system regulation.
For most adults, around 275 mg of elemental magnesium taken about one hour before bed helps support relaxation, sleep readiness, and overnight glucose stability.
If you’re looking for a clean, well-absorbed option, you can find the magnesium glycinate we recommend by clicking here.
Ashwagandha: Lowering Cortisol at the Source
Chronic stress is one of the most overlooked drivers of insulin resistance. Ashwagandha is an adaptogenic herb, meaning it helps normalize the stress response rather than sedating or suppressing it.
This distinction matters. We don’t want cortisol eliminated; we want it rhythmic.
Ashwagandha is also one of the most clinically studied herbs for stress and cortisol regulation. In randomized, double-blind, placebo-controlled trials, standardized ashwagandha extracts have consistently shown reductions in cortisol of roughly 20–30%, along with improvements in perceived stress, anxiety, sleep quality, and overall well-being [3,4].
Because cortisol directly signals the liver to release glucose, lowering cortisol often leads to improvements in fasting glucose, fewer middle-of-the-night awakenings, and better morning energy, even without dietary changes.
Ashwagandha doesn’t lower blood sugar directly. It works upstream by reducing the stress signals that interfere with insulin’s job.
For chronically stressed individuals, 655 mg taken about 1 hour before bed, alongside magnesium glycinate, supports the natural evening downshift, improving sleep and overnight glucose control.
The ashwagandha we recommend is third-party tested and includes black pepper extract to enhance absorption. You can learn more about it by clicking here.
Evening Carbohydrates: Reducing Nighttime Stress Signaling
Many people with insulin resistance spend years under-fueling in the evening, skipping dinner, avoiding carbohydrates, or going to bed with depleted glycogen stores. Physiologically, the body interprets low energy availability as stress, which drives cortisol higher overnight.
Carbohydrates also play an important role in sleep biology. They increase tryptophan availability in the brain, supporting serotonin production, which then converts to melatonin, your primary sleep hormone.
Human research shows that carbohydrate timing and quality influence sleep onset and sleep quality, particularly when carbohydrates are fiber-rich and not excessive.
This does not mean sugar or refined carbs before bed. Refined carbohydrates digest quickly and can worsen nighttime awakenings.
Instead, slow-digesting, fiber-rich carbohydrates included as part of a balanced dinner help replenish liver glycogen and reduce the need for the liver to dump glucose overnight.
Examples include lentils, beans, oats, quinoa, sweet potatoes, and whole fruit paired with protein and fiber.
For most people, finishing dinner around 6:30–7:00 pm allows digestion to occur without going to bed under-fueled, supporting both sleep and blood sugar regulation.
Morning Light: The Most Overlooked Insulin Sensitivity Tool
Your insulin sensitivity follows your circadian rhythm, and the strongest signal that sets that rhythm is morning light exposure.
Consistent morning light anchors your internal clock, lowers evening cortisol, improves nighttime melatonin, and enhances insulin sensitivity earlier in the day. Human studies show that when circadian rhythms are disrupted, blood sugar control worsens, even when diet doesn’t change.
The fix is simple: get 10–20 minutes of outdoor light within the first hour of waking, ideally without sunglasses. Even cloudy days work.
This tells your brain it’s daytime, allowing cortisol to peak earlier and fall properly at night, so your body can actually rest and recover.
Putting It All Together
This isn’t about one supplement or one habit. It’s about stacking physiology in your favor:
- Magnesium supports insulin signaling and a calm nervous system
- Ashwagandha lowers cortisol and stress reactivity
- Fiber-rich evening carbohydrates reduce nighttime stress signaling
- Morning light aligns the circadian rhythm
When these work together, sleep improves, cortisol normalizes, insulin sensitivity increases, and fasting glucose stabilizes.
A Simple Daily Framework
Evening
- 275 mg magnesium glycinate one hour before bed
- 655 mg ashwagandha with black pepper one hour before bed
Balanced dinner with fiber-rich carbohydrates
Morning
- 10–20 minutes of outdoor light within the first hour of waking, before checking your phone
Consistency matters more than perfection.
If you want help putting this into practice, we’ve created free resources and meal plans designed to support insulin sensitivity and sleep.
You don’t need to fight your body.
You need to work with it.
References
[1] Dong JY, Xun P, He K, Qin LQ. Magnesium intake and risk of type 2 diabetes: a meta-analysis. Diabetologia. 2011. https://pmc.ncbi.nlm.nih.gov/articles/PMC3161260/
[2] Rodríguez-Morán M, Guerrero-Romero F. Oral magnesium supplementation improves insulin sensitivity and metabolic control in type 2 diabetic subjects. Diabetes Care. 2003. https://pubmed.ncbi.nlm.nih.gov/12663588/
[3] Chandrasekhar K, Kapoor J, Anishetty S. A prospective, randomized double-blind, placebo-controlled study of safety and efficacy of a high-concentration full-spectrum extract of Ashwagandha root in reducing stress and anxiety. Indian J Psychol Med. 2012. https://pubmed.ncbi.nlm.nih.gov/23439798/
[3] Lopresti AL, Smith SJ, Malvi H, Kodgule R. An investigation into the stress-relieving and pharmacological actions of Ashwagandha: A randomized, double-blind, placebo-controlled study. Medicine (Baltimore). 2019. https://pubmed.ncbi.nlm.nih.gov/31517876/
Diana is a nationally recognized Registered Dietitian and Certified Diabetes Care and Education Specialist (CDCES), and holds a Master’s degree in Nutrition Science and Policy from the Tufts Friedman School of Nutrition. She received her education and dietetics training from Villanova University, Tufts University, and UC San Diego Health. Diana has over 8 years of experience working in the field of type 2 diabetes.
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