Turning to coffee on an empty stomach after a poor night’s sleep could cause more trouble than help, according to researchers who suggest it’s all in the timing if you’re hoping to get a boost from coffee.
Studying how caffeine affects blood sugar and metabolic health, physiologists from the University of Bath (UK) dispute the common-place knowledge that if you didn’t sleep well, you should turn to caffeine. They suggest that drinking coffee, especially on an empty stomach, can set you up for a more sluggish day ahead.
Researchers recruited twenty-nine healthy men and women and tested how their bodies reacted to varying levels of sleep disruption, followed by consuming sugary beverages with and without coffee the next morning. Three sessions of sleep disruption were formed, ranging from normal sleep to a disrupted sleep where they were woken every hour for 5 minutes, and being woken throughout the night sporadically.
Not everyone drinks a sugary beverage in the morning, but the oral glucose test was designed to mimic the same amount of calories and sugar composition you would expect to have in a meal at breakfast.
Previous findings have taught us that being slightly sleep deprived effects how our bodies process food and can even make it harder for us to choose nutritious food the next day. In this study, sleep disruption (not sleep deprivation) did not cause those same effects on the body’s glycemic and insulin responses, but the coffee caused an exaggerated response to the introduction of calories after the nightly fast.
The participants who drank strong black coffee on an empty stomach 30 minutes before drinking the oral glucose test beverage caused the blood sugar to spike 50% more than those who didn’t consume the coffee. The coffee impaired the body’s ability to handle the sugar when the simulated “food” was introduced.
Our bodies’ glucose responses are naturally slightly impaired when it comes to waking after sleeping, which is one of the reasons why choosing a high-quality breakfast is important for stabilizing blood sugar levels through the entire course of the day. Drinking black coffee before you eat breakfast can predispose you to having more severe spikes and crashes in your blood sugar, which can make your whole day worse, especially if you started out after a bad night’s sleep.
Switching your routine to drinking coffee after you’ve had a good breakfast can do your body a favor by helping it stay balanced, and hopefully keep you from needing extra coffee later on.
Smith, Harry A., et al. “Glucose Control upon Waking Is Unaffected by Hourly Sleep Fragmentation during the Night, but Is Impaired by Morning Caffeinated Coffee: British Journal of Nutrition.” Cambridge Core, Cambridge University Press, 1 June 2020, www.cambridge.org/core/journals/british-journal-of-nutrition/article/glucose-control-upon-waking-is-unaffected-by-hourly-sleep-fragmentation-during-the-night-but-is-impaired-by-morning-caffeinated-coffee/398A3EDA8C30EC89ADBB4C74C8E244B0.