Scrolling your phone before sleep? It may be raising your blood sugar

World diabetes day 2025: Doctors warn that late-night scrolling can suppress melatonin, disrupt sleep cycles, raise cortisol, impair glucose control, creating cravings and metabolic strain over time

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We have all been guilty of lying in bed, exhausted, but still glued to our phone, knowing well that we must sleep but it feels almost comforting to scroll until the eyes get heavy. But doctors are now warning that this small nightly habit may be doing more inside the body than we realise. The light from our screens can throw off our sleep rhythm and even nudge blood sugar levels higher, in ways that add up over time.

How does blue light at night interfere with your blood sugar control?

Blue light, the kind emitted from phones, tablets, and TVs, is a powerful suppressant of melatonin, the hormone that helps your body wind down for sleep. But melatonin also influences glucose metabolism.

 

“When melatonin levels drop, the circadian rhythm is disrupted, leading to impaired insulin secretion from the pancreas,” explains Dr Mohit Sharma, Senior Consultant, Internal Medicine, Amrita Hospital, Faridabad. “This means the body becomes temporarily less efficient at moving glucose into cells, causing higher blood sugar levels at night and early morning.”

 

It doesn’t stop there. Circadian misalignment alters cortisol, the stress hormone, keeping it elevated at night, and high cortisol levels are known to raise blood glucose further. “Basically, your late-night scrolling is teaching your body to behave as though it’s daytime, metabolically speaking,” said Dr Sharma.

What exactly happens when your sleep is disrupted?

Dr Sharma points out that deep and REM (Rapid Eye Movement) sleep phases are when the body “resets” its metabolism. “Screen use before bed delays these stages and increases sympathetic activity where your body stays partially ‘on alert’,” he says.

 

Even a single night of poor sleep can cause a measurable dip in insulin sensitivity the next morning. When your liver doesn’t get the memo that it’s bedtime, it keeps producing glucose (a process called gluconeogenesis), leaving you with elevated fasting sugar levels. Over time, this pattern can edge you closer to insulin resistance, which is the gateway to type 2 diabetes.

Does binge-watching or scrolling make you crave more sugar the next day?

Absolutely. Lack of sleep skews the delicate balance between the hunger hormones ghrelin and leptin. Ghrelin rises, leptin drops, and suddenly, that doughnut looks like a brilliant idea.

 

“Sleep-deprived individuals consume more calories, especially from refined carbs and sugary foods,” says Dr Sharma. “The brain’s reward centres light up more strongly in response to junk food.” That’s why a single night of binge-watching can easily spiral into an entire day of sugar crashes and cravings.

 

“For people with diabetes or prediabetes, these effects are amplified,” says Dr Sharma. “They already have impaired insulin function. When melatonin suppression or circadian disruption occurs, their bodies struggle even more to bring glucose levels back to normal.”

 

Dr Chitra S, HOD & Consultant, Endocrinology, Ramaiah Memorial Hospital, Bengaluru, adds that in individuals with insulin resistance, the hormonal system is already working harder to maintain equilibrium. “If the sleep-wake cycle is repeatedly disturbed, hormones like cortisol never fully reset,” she says. “This can mimic a constant state of stress inside the body, pushing up blood glucose, blood pressure, and cholesterol.”

 

She draws a striking parallel: “Shift workers like nurses, pilots, and doctors who have prolonged circadian disruption show higher rates of diabetes and metabolic disorders over time.”

Is screen time also responsible for emotional eating?

“Screen addiction or binge-watching is often a way of numbing emotional exhaustion,” Dr Chitra observes. “When people are chronically tired, their ability to self-regulate weakens. They turn to screens or food for comfort.”

 

This behaviour, she notes, often leads to late-night snacking, when the digestive system is least equipped to handle food. “More than 25 per cent of daily calorie intake now happens after dinner time in many people,” she says. “This single habit is strongly linked with weight gain and rising blood sugar.”

Can blue-light filters and night modes really help?

“They do help, but not fully,” cautions Dr Sharma. “The best protection still comes from switching off screens at least 60–90 minutes before bed.”

 

Dr Chitra suggests dimming lights three hours before bedtime and exposing yourself to sunlight early in the morning to reset the body’s internal clock.

What digital habits can protect your sleep and blood sugar levels?

Here’s what the experts recommend:

• Create a digital sunset: Set a fixed “screen-off” time 60–90 minutes before bed
• Keep devices out of the bedroom: Out of sight, out of mind
• Shift to low-stimulation activities: Audiobooks, calming music, meditation, or paper reading
• Use red or warm lighting: Red light least affects melatonin
• Maintain a regular sleep schedule: Go to bed and wake up at the same time every day
• Avoid caffeine or energy drinks 5–6 hours before bed
• Do a ‘to-do dump’ before sleep: Write down tomorrow’s tasks to calm a racing mind

“Good sleep isn’t just about feeling rested; it’s your body’s most underrated tool for blood sugar balance, hormone regulation, and emotional resilience,” concluded Dr Sharma.

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This content is for informational purposes only and is not a substitute for professional medical advice.