Sleeping Late On Weekends And Getting Up Early On Weekdays? It's Bad For Health, Says Study

Inconsistent sleep patterns can affect health (Pic: Pexels; Representational Purposes)

Irregular sleep patterns like late sleeping on weekends, and waking early on workdays could be associated with harmful bacteria in your gut and negatively affect your health, suggests research. The study, published in The European Journal of Nutrition, is the first to find multiple associations between social jet lag - the shift in your internal body clock when your sleeping patterns change between workdays and free days - and diet quality, diet habits, inflammation and gut microbiome composition in a single cohort. Previous research has shown that working in shifts disrupts the body clock and can increase the risk of weight gain, heart problems and diabetes. 

However, there is less awareness that our biological rhythms can be affected by smaller inconsistencies in sleeping patterns due to waking early with an alarm clock on workdays, for example, compared to waking naturally on non-work days for people working regular hours. Researchers found that just a 90-minute difference in the timing of the midpoint of sleep - the halfway point between sleep time and wake-up time - is associated with differences in gut microbiome composition.

Having social jet lag was associated with lower overall diet quality, higher intakes of sugar-sweetened beverages, and lower intakes of fruits and nuts, which may directly influence the abundance of specific microbiota in your gut. “Sleep is a key pillar of health, and this research is particularly timely given the growing interest in circadian rhythms and the gut microbiome. Even a 90-minute difference in the mid-point of sleep can encourage microbiota species which have unfavourable associations with your health,” said Kate Bermingham, from King’s College London.

“Maintaining regular sleep patterns, so when we go to bed and when we wake each day, is an easily adjustable lifestyle behaviour we can all do, that may impact your health via your gut microbiome for the better,” added Dr Sarah Berry from King’s College London.  The composition of the microbes in your gut (microbiome) may negatively or positively affect your health by producing toxins or beneficial metabolites. Specific species of microbes can correspond to an individual’s risk of long-term health conditions such as diabetes, heart disease and obesity. 

The microbiome is influenced by the food you consume which makes the diversity of your gut adjustable.  In a cohort of 934 people, researchers assessed blood, stool and gut microbiome samples as well as glucose measurements in those whose sleep was irregular compared to those who had a routine sleep schedule. 

While previous studies into the association between social jet lag and metabolic risk factors have been done in populations with obesity or diabetes, this cohort consisted of mainly lean and healthy individuals with most getting more than seven hours sleep per night throughout the week. Three out of the six microbiota species more abundant in the social jet lag group have ‘unfavourable’ associations with health. These microbes are associated with poor diet quality, indicators of obesity and cardiometabolic health, and markers in your blood related to higher levels of inflammation and cardiovascular risk.