Not getting enough sleep is a common affliction in the modern age. If you don’t always get as many hours of shut-eye as you’d like, perhaps you were concerned by news of a recent study that found people who sleep less than six hours a night are at higher risk of type 2 diabetes.

So what can we make of these findings? It turns out the relationship between sleep and diabetes is complex.

The study

Researchers analysed data from the UK Biobank, a large biomedical database which serves as a global resource for health and medical research. They looked at information from 247,867 adults, following their health outcomes for more than a decade.

The researchers wanted to understand the associations between sleep duration and type 2 diabetes, and whether a healthy diet reduced the effects of short sleep on diabetes risk.

As part of their involvement in the UK Biobank, participants had been asked roughly how much sleep they get in 24 hours. Seven to eight hours was the average and considered normal sleep. Short sleep duration was broken up into three categories: mild (six hours), moderate (five hours) and extreme (three to four hours). The researchers analysed sleep data alongside information about people’s diets.

Some 3.2% of participants were diagnosed with type 2 diabetes during the follow-up period. Although healthy eating habits were associated with a lower overall risk of diabetes, when people ate healthily but slept less than six hours a day, their risk of type 2 diabetes increased compared to people in the normal sleep category.

The researchers found sleep duration of five hours was linked with a 16% higher risk of developing type 2 diabetes, while the risk for people who slept three to four hours was 41% higher, compared to people who slept seven to eight hours.

One limitation is the study defined a healthy diet based on the number of servings of fruit, vegetables, red meat and fish a person consumed over a day or a week. In doing so, it didn’t consider how dietary patterns such as time-restricted eating or the Mediterranean diet may modify the risk of diabetes among those who slept less.

Also, information on participants’ sleep quantity and diet was only captured at recruitment and may have changed over the course of the study. The authors acknowledge these limitations.

Why might short sleep increase diabetes risk?

In people with type 2 diabetes, the body becomes resistant to the effects of a hormone called insulin, and slowly loses the capacity to produce enough of it in the pancreas. Insulin is important because it regulates glucose (sugar) in our blood that comes from the food we eat by helping move it to cells throughout the body.

We don’t know the precise reasons why people who sleep less may be at higher risk of type 2 diabetes. But previous research has shown sleep-deprived people often have increased inflammatory markers and free fatty acids in their blood, which impair insulin sensitivity, leading to insulin resistance. This means the body struggles to use insulin properly to regulate blood glucose levels, and therefore increases the risk of type 2 diabetes.

Further, people who don’t sleep enough, as well as people who sleep in irregular patterns (such as shift workers), experience disruptions to their body’s natural rhythm, known as the circadian rhythm.

This can interfere with the release of hormones like cortisol, glucagon and growth hormones. These hormones are released through the day to meet the body’s changing energy needs, and normally keep blood glucose levels nicely balanced. If they’re compromised, this may reduce the body’s ability to handle glucose as the day progresses.

These factors, and others, may contribute to the increased risk of type 2 diabetes seen among people sleeping less than six hours.

While this study primarily focused on people who sleep eight hours or less, it’s possible longer sleepers may also face an increased risk of type 2 diabetes.

Research has previously shown a U-shaped correlation between sleep duration and type 2 diabetes risk. A review of multiple studies found getting between seven to eight hours of sleep daily was associated with the lowest risk. When people got less than seven hours sleep, or more than eight hours, the risk began to increase.

The reason sleeping longer is associated with increased risk of type 2 diabetes may be linked to weight gain, which is also correlated with longer sleep. Likewise, people who don’t sleep enough are more likely to be overweight or obese.

Good sleep, healthy diet

Getting enough sleep is an important part of a healthy lifestyle and may reduce the risk of type 2 diabetes.

Based on this study and other evidence, it seems that when it comes to diabetes risk, seven to eight hours of sleep may be the sweet spot. However, other factors could influence the relationship between sleep duration and diabetes risk, such as individual differences in sleep quality and lifestyle.

While this study’s findings question whether a healthy diet can mitigate the effects of a lack of sleep on diabetes risk, a wide range of evidence points to the benefits of healthy eating for overall health.

The authors of the study acknowledge it’s not always possible to get enough sleep, and suggest doing high-intensity interval exercise during the day may offset some of the potential effects of short sleep on diabetes risk.

In fact, exercise at any intensity can improve blood glucose levels.

Giuliana Murfet, Casual Academic, Faculty of Health, University of Technology Sydney and ShanShan Lin, Senior Lecturer, School of Public Health, University of Technology Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.

I live on the edge of Parramatta, Australia’s fastest-growing city, on the kind of old-fashioned suburban street that has 1950s fibros constructed in the post-war housing boom, double-storey brick homes with Greek columns that aspirational migrants built in the 1970s and half-crumbling, Federation-era mansions once occupied by people whose names still appear in history textbooks.

Parramatta’s population is predicted to almost double in the next 20 years. My street, like so many others, has recently been rezoned for high-density living. Many of these houses are being sold to developers.

It’s a local story but it’s also a national one: suburbs near our cities are disappearing everywhere along with the crucial histories of Australian life they represent.

Australia is still a suburban nation: 70% of us live in the suburbs and this figure is increasing with the rapid growth of “McMansion” areas in the far outskirts of our cities.

Suburbia looms large in our imagining of ourselves, so what happens when we lose those suburban streets whose houses are too young to be heritage-listed but still old enough to tell an important story of our social and economic history? As urban researcher Larry Bourne argued, we have yet to really write the history of suburban life because we haven’t paid enough attention to recording the private everyday experiences of people and their homes there.

So that’s what I’ve been doing for the past several months, walking the street with suburban photographer Garry Trinh and talking to my neighbours about their relationships with their homes before they are lost.

‘A different attitude to life’

A few houses down from me, Craig lives in a cottage that he believes “shows a different attitude towards life”. He spends his weekends restoring parts of his home.

It takes a lot of time to maintain. People took longer to do things. They had a different sense of time – they did things one time so they didn’t have to do it again.

He enjoys the idea that living in a house like this “you grow old together”. He shows me the places where the tiles on the floor don’t fit perfectly. The “walls and roofs are never even”, but that’s part of the place’s charm – you can see where others have added a living room or tried to fix a leak.

These homes have layers of history that don’t exist anywhere else.

To Craig, these houses represent why other generations felt more of the kind of safety and security that allowed them to build a greater sense of community.

You used to buy one house and you never changed it, one car […] people stayed in the same place […] people feel so restless now because we are no longer safe. Everything changes. Our houses are rezoned. There’s no certainty.

‘Edible things in people’s yards’

Jenny’s parents bought the largest block on the end of the street because the previous owners refused to sell to developers. She recently moved back home to care for her mother.

It’s a sprawling Federation-era home called “Coo-Wong” and it feels like big history must have happened there, despite its absence from any local history archives. There are clues, though, about the kind of people who might have lived here before: Chinese coins found on the property, a shed full of bric-a-brac.

Mostly, the whole family lives in the kitchen or the light-filled corner at the back of the house where Jenny’s mother grows flowers. Her father’s family lost everything during the Cultural Revolution and he moved here to find a better life. He’s in the building industry and their home is filled with the spare parts from other houses, doors, drawers and other supplies that might go into extending or renovating their home one day.

Jenny remembers when they moved into the neighbourhood there was an older generation of people who embraced them. There were fruit trees and “all of these edible things in people’s yards”. In their backyard, a giant satellite dish, which her parents bought to watch their shows from China, still looms big even if it isn’t needed anymore.

It’s these small details in Jenny’s home that tell the larger story of how various generations of migrants sewed themselves into the fabric of our suburbs.

Different versions of one house

George, his wife, Jennifer, and their two adult children live in the house George’s father built in 1973 when the street was filled with vacant blocks. His family was the first to move here from their village in Lebanon, so their house became a kind of community hub – there were always people there.

George’s family passed the plans he used to build the house onto other Lebanese families that moved in. It means there are slightly different versions of this house in many other places on the street.

George’s dad and his uncles built many houses in this area together. Sometimes they didn’t quite get it right though: only one door in their house is hung straight – all the rest are hung backwards. The family has been trying to restore parts of the house for a long time, including the Art Deco railings and Victorian lights.

As an expert in post-war housing, Mirjana Lozanovska says this layering of architectural details found in these post-war suburban homes “expanded the image and aesthetic spectrum of what it is to be Australian”.

A long row of houses for sale

Carol lives in a long row of houses at the end of the street that are all for sale. She has, to put it lightly, a lot of stuff. Her odd collection of tents and furniture and well-loved succulents spill from her house to its immense lawns.

The quest for affordable housing has pushed Carol further and further west over time. When the landlord sells the house she’ll head further away, looking for some other suburban street where the houses are still intact and maybe there’ll still be lemon trees.

Felicity Castagna, Lecturer, Creative Writing, Western Sydney University

This article is republished from The Conversation under a Creative Commons license. Read the original article.