A strong, black coffee to wake you up after a bad night’s sleep could impair control of blood glucose levels, according to a new study.
Research from the Centre for Nutrition, Exercise & Metabolism at The University of Bath (UK) looked at the impact of sleep and morning coffee across a range of distinct metabolic markers.
The scientists show that while one night of poor sleep has limited impact on our metabolism, drinking coffee for a way to perk you up out of sleep may have a negative effect on blood glucose (sugar) control.
Given the significance of maintaining our blood sugar levels within a secure range to reduce the risk of conditions like diabetes and cardiovascular disease, they say these results may have ‘far-reaching’ health consequences, especially considering the international popularity of coffee.
For their analysis, the physiologists in the University of Bath requested 29 healthy men and women to experience three different overnight experiments in a random sequence:
In one, condition participants had a regular night’s sleep and were asked to consume a sugary beverage on waking in the morning.
On a second occasion, participants experienced a disrupted nighttime’s sleep (in which the researchers woke them every hour for five minutes) then upon waking were awarded exactly the exact same sugary beverage.
On another, participants experienced exactly the exact same sleep disruption (i.e. being woken through the night) but that time were first given a strong black coffee 30 minutes prior to swallowing the sugary drink.
In all these evaluations, blood samples from participants were taken after consuming a glucose beverage that in energy content (calories) mirrored what might typically be absorbed for breakfast.
Their findings highlight that one night of disrupted sleep failed to worsen participants’ blood glucose / insulin reactions at breakfast, when compared to a regular night’s sleep. Past research indicates that losing many hours of sleep within one or two multiple nights can have adverse metabolic effects, so it’s reassuring to find out that one night of sleep (e.g. because of insomnia, noise disturbance or a brand new baby) does not have exactly the exact same effect.
However, strong black coffee consumed prior to breakfast considerably increased the blood glucose reaction to breakfast by approximately 50%. Although population-level polls indicate that coffee might be connected to wellbeing, past research has previously demonstrated that caffeine has the potential to trigger insulin resistance. This new study therefore reveals that the common remedy of drinking coffee after a lousy night’s sleep can solve the problem of feeling sleepy but could create another by limiting your body’s ability to process the glucose in your breakfast.
Co-Director of the Centre for Nutrition, Exercise and Metabolism at the University of Bath who oversaw the work, explains: “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.”
“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 the need it. Knowing this can have important health benefits for us all.”
Lead writer, Harry Smith From the Department for Health in Bath added: “These results demonstrate that one night of disrupted sleep alone failed to worsen participants’ blood glucose/insulin response to the carbonated beverage compared to a normal night of sleep that is reassuring to many people. But, beginning a day after a bad night’s sleep with a solid coffee did have a negative effect on glucose metabolism by approximately 50%.”
“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%.
“As such, individuals should try to balance the potential stimulating benefits of caffeinated coffee in the morning with the potential for higher blood glucose levels and it may be better to consume coffee following breakfast rather than before.
“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.”
Coffee has become the world’s most popular beverage, with around two billion cups consumed every day. In the US roughly half of the people in America aged 18 and over drink coffee each day, whilst at the UK, according to the British Coffee Association, 80% of families purchase instant coffee.