How Sleep Affects Blood Sugar and Heart Health

The connection

Short or disrupted sleep increases stress hormones like cortisol, affects appetite hormones (making you hungrier for high-carbohydrate foods), and makes cells less responsive to insulin. Over time, consistently sleeping under six hours is associated with higher risk of type 2 diabetes, high blood pressure and heart disease.

Sleep apnoea

Obstructive sleep apnoea — repeated pauses in breathing at night — is common in people with type 2 diabetes and high blood pressure. Signs include loud snoring, gasping, morning headaches and daytime sleepiness. It is treatable, and treatment can improve blood pressure. Ask your doctor about testing if this sounds familiar.

Better sleep habits

• Keep a consistent sleep and wake time, even on weekends.
• Aim for 7–9 hours.
• Keep the bedroom dark, cool and quiet.
• Limit caffeine after early afternoon and avoid heavy meals late at night.
• Reduce screen use in the hour before bed.
• Get daylight exposure in the morning.

Night-time glucose

If you have diabetes and wake with high readings, it could be due to the 'dawn phenomenon' (natural early-morning hormone rise), late snacks, or medication timing. Track patterns and discuss them with your care team.

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