Doing This at Night Spikes Your Risk of Diabetes and Heart Disease, New Study Says


Some people love getting up at the crack of dawn, finding that those quiet early morning hours are the best time to be productive and get grounded for the day ahead. Others get a burst of energy in the evening, reaching their peak creative state as the day winds down. But whether you're an early riser or a night owl, your sleep habits can significantly impact your health—for better or worse.

A study published in the Sept. 2022 edition of Experimental Physiology found that your preferred bedtime can put you at a higher risk of developing chronic diseases, including diabetes and heart disease. Read on to learn how your sleep schedule could jeopardize your health, and what you can do about it.

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Your chronotype has a big impact on your health.

Your body's naturally preferred times to sleep and wake up is known as your "chronotype," explains the Sleep Foundation. Early birds, or morning larks, tend to go to sleep and wake up earlier and have more energy in the morning, while night owls prefer staying up late and sleeping in later.

Chronotypes can significantly impact your health, affecting appetite, energy levels, recovery, and core body temperature. Knowing and understanding your chronotype can help you make healthy choices around your sleep schedule, so you can feel more energetic and alert—as well as reducing your risk of diabetes and heart disease.

Christina Abavana, MD, a sleep medicine specialist with Hartford HealthCare, tells Best Life, "Night owls tend to be less physically active due to sleep deprivation. Sleep deprivation increases ghrelin (the hunger hormone), which may lead to increased carb intake. Our chronotype also plays a role in appetite and hormone regulation, which may be altered when late chronotypes fight their natural sleep-wake cycle."

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Your chronotype can change throughout your life.
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According to the Sleep Foundation, chronotypes fall on a spectrum, with most of us landing somewhere in the middle. However, your chronotype can change at various stages throughout your life. For example, most children are early birds, but turn into night owls during adolescence (hence the myth that teenagers are lazy and love sleeping late). Once they reach adulthood, their chronotype begins shifting earlier, starting at age 20.

"Your chronotype cannot be changed drastically," says Abavana. "Chronotype is governed mostly by your genes, age, and gender. Also, your chronotype may shift as you get older."

Night owls have a higher risk of chronic disease.

The study looked at the biological differences of 51 participants who had metabolic syndrome—a cluster of conditions that spike your risk of heart disease, including hypertension, high blood sugar, excess body weight, and high cholesterol. Participants were split into two groups based on questionnaires designed to help determine early and late chronotypes. Researchers performed various tests to measure body mass and composition, insulin sensitivity, and metabolic function. All participants adhered to a strict calorie and nutrition-restricted diet while fasting overnight.

The researchers observed that the participants' chronotypes significantly impacted their metabolic functions. For example, night owls were more likely to store fat and carbohydrates during rest and exercise, while early birds were more likely to convert fat into usable energy. In addition, night owls were more insulin-resistant than early birds, which can lead to becoming overweight or obese, significant risk factors for heart disease and Type 2 diabetes.

"Metabolic syndrome is a collection of certain conditions that include high cholesterol, high blood pressure, more fat around your waistline, and problems responding to insulin, such as diabetes," explains Alexa Mieses Malchuk, MD, a board-certified family physician. "Among the people with metabolic syndrome who were studied, early chronotypes metabolized fat better than late chronotypes, regardless of physical activity. On the bright side, if late chronotypes exercised, they too could ramp up their metabolism."

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Gradually shifting your chronotype can help safeguard you from disease.
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Changing from a night owl to an early bird isn't as simple as deciding to go to bed super early and set your alarm to go off before sunrise. Research indicates that chronotypes are genetic, meaning that, if you're a night owl, it's in your DNA to stay up late and snooze the morning away. Fortunately, you can take steps to shift your chronotype. The trick is to do it gradually and not shock your body's natural rhythm by making the change overnight.

Adopting healthy lifestyle habits and practicing good sleep hygiene are excellent ways to gradually shift your chronotype toward becoming an early bird. This includes getting outdoors early in the day, doing aerobic exercise regularly, eating a well-balanced, nutritious diet, managing stress, keeping electronics out of your bedroom, and limiting stimulants like caffeine and sugar.