New research shows that a cup of coffee lasts for six hours

A new study has found that the stimulating effect of caffeine can last for six hours, the Daily Mail reported. Drinking coffee after 5pm can easily lead to an hour less sleep at night. Because the coffee drinking time is late, it is easy to lead to night sleep disorder, sleep time shortening and sleep quality decline.

In the new study, Christopher Drake, a professor of psychiatry at Wayne State University in the United States, and his colleagues studied the sleep habits of 12 participants who were given 400 milligrams of caffeine (the equivalent of 2 to 3 cups of coffee). During the four-day trial, participants took caffeine tablets, including a placebo, six hours before bed, three hours before going to bed and before turning off the lights. It turns out that drinking a large cup of espresso after 5pm can lead to sleeplessness at night and drowsiness during the day, and even drinking two or three cups of coffee six hours before going to bed can lead to an hour less sleep. Professor Drake pointed out that many people know that drinking coffee before going to bed can make it hard to fall asleep, but little is known about the fact that drinking coffee in the afternoon can also lead to sleep disorders at night.

Drinking coffee to protect small blood vessels is good for heart health.

A study announced at the annual meeting of the American Heart Association in Dallas shows that drinking coffee is good for heart health because it improves the function of small blood vessels.

Researchers at the University of Ryukyu in Okinawa, Japan, studied 27 healthy adults aged 22 and 30 who did not drink much coffee. Participants drank a cup (5 ounces) of caffeinated or non-caffeinated coffee. After that, the blood flow of small blood vessels at fingertips is measured by laser Doppler blood flow meter (finger blood flow is a window of human small blood vessel function). Two days later, the researchers repeated the experiment with other types of coffee and measured blood pressure, heart rate and vascular resistance levels of the participants. It was found that drinking a cup of caffeinated coffee increased the blood flow of small blood vessels at the fingertips by 30%, and caffeinated coffee improved blood pressure and vascular endothelial cell function.

The researchers said the study explored the effects of caffeine on small blood vessel function for the first time and provided important clues for further exploration of coffee's improvement in cardiovascular health.