According to new research, drinking strong black coffee to wake you up after a bad night’s sleep can lower the management of your blood sugar levels.

A study by the Center for Nutrition, Exercise, and Metabolism at Bath University in the UK observed the effects of disturbed sleep and morning coffee on various metabolic markers.

Scientists say that although one night of poor sleep has a limited effect on human metabolism, drinking coffee to wake up can harm the management of blood sugar levels.

It is very important to keep our blood sugar levels in a safe range to avoid diseases such as diabetes and heart disease. Therefore, scientists say that these results can be of great importance for our health – given the popularity of coffee around the world.

For the study, researchers at Betty University asked 29 healthy men and women to perform three different experiments in random order:

In one, the participants slept normally and were required to drink sugary drinks in the morning.
On the other, participants’ nighttime sleep was disturbed (researchers woke them up for 5 minutes every hour), and in the morning they drank the same sugary drink.
In the third, participants’ sleep was just as disturbed as in the second (i.e., they woke up at night), although this time they were given strong black coffee 30 minutes before their sugary drink in the morning.

During each of these tests, blood samples were taken from participants after consuming a sugary drink, which in terms of energy volume (calories) was equal to the amount of breakfast normally consumed.

Getty Images/Moment/Burak Karademir

The study found that disturbed sleep overnight compared to normal sleep did not worsen participants’ blood glucose/insulin responses at breakfast. We have known from previous studies that disturbing several hours of sleep during one and/or several nights could have adverse metabolic effects, so it is promising to know that overnight fragmented sleep (for example, due to insomnia or noise) does not have the same effect.

Nevertheless, consuming strong black coffee before breakfast significantly increased the blood glucose response to breakfast – by about 50%. While a survey of the population suggests that coffee consumption may be linked to good health, older studies have shown that caffeine has the potential to cause insulin intolerance. Consequently, with this new study, we learn that drinking coffee after a bad sleep can eliminate the problem of drowsiness, but it creates another problem and limits your body’s ability to handle the sugar in your breakfast.