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Does being a “morning person” or a “night owl” have an impact on your weight? A recent study investigated if there is a link between an individual’s sleep cycle and obesity in prediabetes patients.
Your circadian rhythm or “internal clock” is how your brain regulates your sleep-wake cycle over a period of 24 hours. It is also known to influence energy metabolism. A lack of sleep has been shown to have detrimental effects on health, including increasing the risk of obesity and diabetes.
People with prediabetes are encouraged to make lifestyle changes to reduce their risk of developing type 2 diabetes. Prediabetes a condition in which blood sugar levels are higher than normal but not high enough to be diagnosed as diabetes. Typically, these lifestyle changes include changes to their diet and exercise. However, could regulating their sleep cycle also help reduce the risk?
Personal biological clocks control our sleep-wake cycles
Everyone has a sleep chronotype. In other words, everyone has their own personal biological clock controlling their body’s sleep-wake cycle. Sleep chronotypes are affected by a person’s genetics. It determines whether you are a “morning person” or “night owl”, referring to what time of the day you prefer to perform daily activities or sleep.
Night owls have greater social jetlag
Those with a preference for evenings tend to have a later bedtime and greater circadian rhythm misalignment compared to those with a preference for mornings. Also, research has shown night owls are linked to greater social jetlag. Social jetlag is a phenomenon resulting from the change in sleep patterns from workdays to free days. The disruption to your internal body clock resembles the jet lag experienced by travelling across time zones.
Studies suggest a preference for evenings and social jetlag are linked to increased obesity. For example, people on night shift work are at a higher risk of developing obesity. Factors affecting the chronic disruption to their circadian rhythm include significant changes to meal times and poor-quality sleep.
A study conducted by researchers in Thailand and the US explored the relationship between an individual’s morning or evening preference to their body mass index (BMI) in patients with prediabetes. They also looked at whether this relationship is directly linked or is facilitated by factors linked to obesity and eveningness such as social jetlag and a lack of sleep. The findings of the study were recently published in Frontiers in Endocrinology.
The study included 2,133 Asian patients with prediabetes and an average age of 63.6 years. Participants completed a questionnaire to assess their preference for mornings or evenings and underwent interviews to collect data on various sleep characteristics, including average sleep duration per week and sleep quality. Social jetlag was calculated by determining the difference between mid-sleep time on weekdays and weekends. BMIs were also calculated, with the average BMI being 25.8 kg/m2.
Night owls had increased risk of higher BMI
The results showed that as a preference for evenings increased, the duration of sleep decreased. This decrease in sleep duration was in turn negatively associated with BMI. A change in morning to evening preference, such as becoming more of a night owl showed a decrease in sleep duration and an increase in BMI. Therefore, the change to a preference for evenings was directly linked to an increase in BMI.
When social jetlag was taken into consideration with an individual’s preference for mornings or evenings, it was not significantly associated with BMI. However, assessment of a subgroup of patients who were aged 60 years or over showed BMI increased with each hour increase in social jetlag.
Night owls with prediabetes are at higher risk of weight gain
In conclusion, these findings showed how important an individual’s circadian rhythm or internal clock is in energy metabolism. It showed that a preference for evenings was directly linked to increased BMI. Suggesting that patients with prediabetes who prefer evenings, or being a night owl, are at higher risk of weight gain. The increase in BMI was indirectly linked to a lack of sleep and not from social jetlag unless the patient was 60 years or older. In which case, the results showed a link between higher BMIs and greater social jetlag.
Diabetes is a global health burden affecting over 159 million people in the Western Pacific Region (28 countries across the Pacific, Oceania and parts of Asia). With numbers expected to rise by 15% by 2045, the need for additional intensive lifestyle interventions to help prevent diabetes, especially in patients with prediabetes is paramount. Therefore, given timing and sleep duration are also modifiable, changes to sleep patterns is a possible intervention method to help reduce BMI and the potential development of diabetes in this high-risk group.
Written by Lacey Hizartzidis, PhD
Reference: Anothaisintawee T, Lertrattananon D, Thamakaison S, Thakkinstian A, Reutrakul S. The Relationship Among Morningness-Eveningness, Sleep Duration, Social Jetlag, and Body Mass Index in Asian Patients With Prediabetes. Front Endocrinol (Lausanne). 2018;9(August):1-12. doi:10.3389/FENDO.2018.00435.