Caffeine is the world’s most beloved drug and is also widely used among strength athletes – whether or not as the main ingredient in pre-workout supplements. However, the substance can have a negative impact on the duration and quality of your sleep. How exactly does that work? New research provides more clarity.

META-ANALYSIS

The research concerns a meta-analysis of no fewer than 24 studies, all of which examined the effect of caffeine consumption on sleep.

It is well known that caffeine is bad for sleep, but the magnitude of this effect is somewhat underappreciated. Caffeine worsens just about every effect of sleep, the analysis shows, and for much longer periods than most people think.

The researchers conclude:

To avoid reduction in overall sleep time, coffee (107 mg per 250 ml) should be consumed at least 8.8 hours before bedtime and a standard serving of pre-workout supplement (217.5 mg) should be consumed at least 13.2 hours before are consumed before bedtime.

Each individual aspect of sleep doesn’t deteriorate dramatically, but when you put them all together and look at sleep duration and quality, the effects are quite remarkable.

EFFECTS

To be precise, this concerns the following effects:

• Consuming caffeine makes it harder to fall asleep;
• It reduces sleep efficiency;
• It reduces the duration of deep sleep;
• It increases the duration of light sleep;
• It increases the time people stay awake at night.

SUBJECTIVE VERSUS OBJECTIVE

These effects are not the same for everyone and some sleep well, even with caffeine consumption.

But realize that your subjective sleep quality is not necessarily the same as your objective sleep quality. One of the studies showed that even one double espresso in the morning has a negative impact on objective sleep quality the following night.

CONCLUSION

Caffeine undeniably has a negative impact on sleep. How and how much varies from person to person. In general, it is not recommended to drink coffee in the evening.

Even a regular cup of coffee should be consumed at least 9 hours before going to sleep to rule out negative effects. And a pre-workout supplement, which contains an average of 200 mg of caffeine, should be consumed at least 13 hours in advance. Good to know if you train in the evening.

Not all negative effects are clearly noticeable, but they can still have a negative impact on one or more aspects of your sleep.