How much caffeine can you have while still being able to sleep well?

While many of us rely on caffeine to stay energized throughout the day, excessive consumption can disrupt sleep and cause daytime restlessness. The FDA advises adults to limit caffeine intake to 400 milligrams per day, which is roughly equivalent to four cups of coffee.

So, how can you optimize caffeine consumption to get the most out of it?

According to Astrid Nehlig, director of research at the French Institute of Health and Medical Research, 100 to 150 milligrams of caffeine, which amount to roughly one to one and a half cups of coffee, has a noticeable effect on alertness.

She explained that the impact of caffeine kicks in within five minutes of consumption, peaking between 15 minutes to two hours, depending on factors such as food intake and metabolism speed.

However, the British Daily Mail reported that excessive caffeine intake can have negative effects.

Moreover, in a study published in the New England Journal of Medicine, participants who consumed their preferred amount of coffee slept an average of 30 minutes less, compared to days when they had no caffeine in their system.

Alternatively, Gregory Marcus, a cardiologist and professor of medicine at the University of California, told The Wall Street Journal in relation to caffeine’s influences on sleep patterns that each person reacts differently. It all depends on individual metabolism rates. Those with slower metabolism slept nearly an hour less a night, while those with faster metabolism did not experience reduced sleep.

To reap the benefits of coffee, minimize sleep difficulties, and avoid a heightened sense of stress, experts suggest delaying the first coffee intake to around 11:00 a.m.

While this may help maintain alertness throughout the workday, it may interfere with nighttime sleep. Excessive caffeine consumption blocks receptors for sleep-regulating hormones like adenosine and melatonin.

Experts recommend abstaining from caffeine approximately six hours before bedtime to secure restful nighttime sleep.

Lack of sufficient sleep is associated with various health problems, including heart disease, kidney disease, high blood pressure, diabetes, and obesity.

The US Centers for Disease Control and Prevention emphasizes the importance of getting eight hours of sleep per night. However, surveys indicate that one out of every three adults fails to reach this recommended amount.