A strong, black coffee after a bad night’s sleep could impair the control of your blood sugar levels, according to a new study. Read why and what to do instead.
Research from the Centre for Nutrition, Exercise & Metabolism at the University of Bath (UK) looked at the effect of broken sleep and morning coffee across a range of different metabolic markers.
Writing in the British Journal of Nutrition the scientists show that whilst one night of poor sleep has a limited impact on our metabolism, drinking coffee as a way to perk you up from a slumber can have a negative effect on blood glucose (sugar) control.
Given the importance of keeping our blood sugar levels within a safe range to reduce the risk of conditions, such as diabetes and heart disease, they say these results could have ‘far-reaching’ health implications, especially considering the global popularity of coffee.
For their study, the physiologists at the University of Bath asked 29 healthy men and women to undergo three different overnight experiments in random order: Those that consumed strong black coffee before breakfast substantially increased their blood glucose response to breakfast by around 50%.
Put simply, our blood sugar control is impaired when the first thing our bodies come into contact with is coffee especially after a night of disrupted sleep. We might improve this by eating first and then drinking coffee later if we feel we still feel need it.Professor James Betts, Co-Director of the Centre for Nutrition, Exercise and Metabolism at the University of Bath
Although population-level surveys indicate that coffee may be linked to good health, past research has previously demonstrated that caffeine has the potential to cause insulin resistance. This new study, therefore, reveals that the common remedy of drinking coffee after a bad night’s sleep may solve the problem of feeling sleepy but could create another by limiting your body’s ability to tolerate the sugar in your breakfast.
“We know that nearly half of us will wake in the morning and, before doing anything else, drink coffee – intuitively the more tired we feel, the stronger the coffee. This study is important and has far-reaching health implications as up until now we have had limited knowledge about what this is doing to our bodies, in particular for our metabolic and blood sugar control,” he said.
How to avoid blood sugar impairment
Put simply, Betts said our blood sugar control is “impaired” when the first thing our bodies come into contact with is coffee especially after a night of disrupted sleep.
There is a solution. “We might improve this by eating first and then drinking coffee later if we feel we still feel need it. Knowing this can have important health benefits for us all,” said Betts.
Lead researcher, Harry Smith from the Department for Health at Bath added: “These results show that one night of disrupted sleep alone did not worsen participants’ blood glucose/insulin response to the sugary drink compared to a normal night of sleep which will be reassuring to many of us.
“However, starting a day after a poor night’s sleep with a strong coffee did have a negative effect on glucose metabolism by around 50%,” said Smith.
Smith continued: “There is a lot more we need to learn about the effects of sleep on our metabolism, such as how much sleep disruption is necessary to impair our metabolism and what some of the longer-term implications of this are, as well as how exercise, for instance, could help to counter some of this.”
The full study ‘Glucose control upon waking is unaffected by hourly sleep fragmentation during the night, but is impaired by morning caffeinated coffee’ is published in the British Journal of Nutrition https://doi.org/10.1017/S0007114520001865.
This work was funded by the University of Bath.