The new study examined the combined effects of insomnia and caffeine on our metabolism – with surprising results.
A strong black coffee that wakes you up after a bad night’s sleep could interfere with blood sugar control, according to a new study.
Research from the Center for Nutrition, Exercise and Metabolism at the University of Bath (UK) looked at the effects of sleep disorders and morning coffee on a number of different metabolic markers.
In the British Journal of Nutrition, scientists write that while a night of poor sleep has limited effects on our metabolism, drinking coffee as a means of getting you out of sleep can negatively affect blood sugar (sugar) control.
Given the importance of keeping our blood sugar levels within safe ranges to reduce the risk of conditions like diabetes and heart disease, these results could have far-reaching health implications, especially given the global popularity of coffee.
For their study, the University of Bath physiologists asked 29 healthy men and women to perform three different experiments overnight in a random order:
- In one case, participants with the condition had normal sleep and were asked to have a sugary drink when they woke up in the morning.
- On another occasion, participants had a sleep disorder (where the researchers woke them up for five minutes every hour) and were then given the same sugary drink when they woke up.
- In another, participants had the same sleep disorder (i.e. they were woken up all night), but this time they were given a strong black coffee 30 minutes before consuming the sugary drink.
In each of these tests, blood samples were taken from participants after the glucose drink, which reflected in energy content (calories) what could normally be consumed at breakfast.
Their results show that one night’s sleep disturbance did not worsen the participants’ blood sugar / insulin responses at breakfast compared to normal sleep. Previous research suggests that losing many hours of sleep over one and / or more nights can negatively impact your metabolism. Therefore, it’s comforting to learn that a single night of fragmented sleep (e.g., due to insomnia, noise nuisance, or a newborn baby) doesn’t have the same effect.
However, strong black coffee consumed before breakfast increased the blood sugar response to breakfast significantly by around 50%. Although population-level surveys suggest that coffee may be linked to good health, previous research has shown that caffeine has the potential to cause insulin resistance. So this new study shows that the common remedy of drinking coffee after a bad night’s sleep can solve the drowsiness problem, but it can create another by limiting your body’s ability to tolerate the sugar in your breakfast.
Professor James Betts, co-director of the Center for Nutrition, Exercise and Metabolism at the University of Bath, who oversaw the work, explains: “We know that almost half of us wake up in the morning and most of all drink coffee – intuitively, ever the more tired we feel, the stronger the coffee. This study is important and has far-reaching health implications as we currently have limited knowledge of what this means for our bodies, especially for our metabolic and blood sugar control.
“Simply put, our blood sugar control is compromised the first time our bodies come in contact with coffee, especially after a night of insomnia. We could improve this by eating first and then drinking coffee later if we feel we still need it. Knowing this can have important health benefits for all of us. “
Lead researcher Harry Smith of the Bath Department of Health added, “These results show that nighttime sleep disorder alone does not worsen participants’ blood sugar / insulin response to the sugary drink compared to a normal night of sleep, which will be comforting to many from us. However, starting with a strong coffee one day after a bad night’s sleep negatively impacted glucose metabolism by about 50%. Therefore, individuals should try to balance the potential stimulatory benefits of caffeinated coffee in the morning with the potential for higher blood sugar levels. It may be better to consume coffee after breakfast than before.
“We have a lot more to learn about the effects of sleep on our metabolism. For example, how much sleep disorder is required to affect our metabolism, what the long-term effects are, and how much exercise we get. could for example help to counteract some of this. “
This week marks International Coffee Day (October 1st) in celebration of the widespread appeal of coffee around the world. Coffee is the most popular drink in the world today. Around two billion cups are consumed every day. Half of all people in the US aged 18 and over drink coffee every day, while in the UK 80% of households buy instant coffee for their own consumption, according to the British Coffee Association.
Reference: “Waking glucose control is not affected by hourly sleep fragmentation during the night, but is affected by caffeinated coffee in the morning” by Harry A. Smith, Aaron Hengist, Joel Thomas, Jean-Philippe Walhin, Philippa Heath, Oliver Perkin, Yung-Chih Chen, Javier T. Gonzalez and James A. Betts, June 1, 2020, British Journal of Nutrition.
DOI: 10.1017 / S0007114520001865