Smart phones and sugar have an unusual link.
Using your smart phone, particularly just before bedtime, leads to shorter sleep time and shorter sleep makes you more likely to drink sugary caffeinated drinks.
The information comes from two studies at the University of California in San Francisco.
Exposure to smart phone screens was associated with poor sleep quality and less sleep overall in one study.
An app was installed on the phones of the participants which recorded the amount of time they spent on screen and their sleeping hours and quality of sleep over a 30 day period.
It was found that the longer the participants spent on screen, particularly before bedtime, the poorer the quality of their sleep. They also spent less time asleep.
In a completely separate study at the same university, researchers found that people who sleep for five or fewer hours each night are much more likely to drink sugary caffeinated drinks during the day.
This study looked at more than 18,000 adults and found those who slept five or fewer hours drank 21pc more caffeinated sugar drinks.
Those who slept six hours a night regularly consumed 11pc more of the drinks than people sleeping seven to eight hours a night.
The link was purely with an increase in the number of carbonated and non carbonated sugary, caffeinated drinks.
There was no association between sleep and drinking juice or tea.
“Short sleepers may seek out caffeinated sugar-sweetened beverages to increase alertness and stave off daytime sleepiness,” said Dr Aric Parther, assistant professor of psychiatry at the university.
“However, it’s not clear whether drinking such beverages affects sleep patterns, or if people who don’t sleep much are more driven to consume them. “Unfortunately, the data in the current study do not allow us to draw any conclusions about cause and effect.”
He stressed that the study may point to a new way to address the problem of excess sugar consumption.
“Sleeping too little and drinking too many sugary drinks have both been linked to negative metabolic health outcomes, including obesity,” added Dr Prather.
“Given the likely two-way relationship between sugary drinks and short sleep, enhancing the duration and quality of sleep could be a useful new intervention for improving the health and well-being of people who drink a lot of sugary beverages.”
The studies are published in the journal Sleep Health and in the open-access journal PLOS ONE.