Caffeine and Sleep: Can Caffeine Make You Sleepy?

What Caffeine Does Actually to Your Body?

can caffeine make you sleepy

Caffeine is a nervous system stimulant that is found naturally in food and beverages such as tea, colas, coffee, chocolate bars, energy bars, soft drinks and energy drinks. Caffeine is also found in botanical products such as kola nuts, Guarana, Yerba mate and certain leaves and fruits from plants. It is also available in prescription and non-prescription medications such as cough syrup and slimming tablets.

In small amounts, caffeine can make you feel refreshed and focused, but in large doses, you are likely to feel anxious and have difficulty sleeping. Like any other drug, it is possible to develop a tolerance to caffeine and you will need much more doses so as to achieve the same effect.

Caffeine works in the body in a similar way as the adrenaline hormone. Some of the signs and symptoms of excessive amounts of caffeine are dehydration, restlessness, frequent urination, anxiety, irritability, trembling hands, fatigue and a rise in body temperature.

Can caffeine make you sleepy? How one reacts to caffeine depend on the body mass, metabolism and whether the body is used to getting regular doses of caffeine. Generally, 400mg in a day or less is an acceptable dose of caffeine.

Who Should Consider When Using Caffeine

Pregnant Women

who should consider when using caffeine

Caffeine should either be avoided or limited to 300mg per day or less. Consuming high amount of caffeine can lead to miscarriage, having a baby with low birth weight or experiencing difficulty during birth.


Caffeine is listed as a prohibited substance under the world anti-doping code 2015. However, it is good to check the anti-doping rules for your particular sport rules on caffeine.


Caffeine intake should be monitored if the child shows symptoms of interrupted sleep, irritability, inability to sleep or stomach upsets.

Caffeine Effects on Sleep

Caffeine readily affects sleep in humans. There is an association between daily intake of caffeine, daytime sleepiness and sleep problems.

The most noticeable effects of caffeine on sleep, even with a single cup of coffee consist of prolonged sleep latency, increases in light sleep, shortening in deep sleep and shorter total sleep time as well as frequent awakening during sleep. You are likely to sleep more when you decide to take a nap during the day due to the increase in light sleeping. These effects are not only caused by the amount of caffeine taken during bedtime, but also by the amount taken during the day. The effects of caffeine are also smaller in habitual coffee drinkers than in occasional drinkers.

The lack of sleep during the night will cause daytime sleepiness. Coffee taken during the day will cause restless nights and disturbed sleep, which make you wake up feeling tired. Caffeine also make you have nocturnal sleep, but in most cases this depends on the amount taken and the genetic background of an individual.

Positive Effects

Caffeine is considered an effective alerting agent and it can have a positive effect on your mood and mental performance, as well as your reaction time. A normal dose of caffeine is between 50mg to 200mg. Caffeine works best when taken during an off and on basis. A cup of coffee increases alertness and concentration during situations of low arousal. Caffeine may also improve performance during work at night and safety during night driving.

Negative Effects

Individuals need seven to eight hours of sleep every night, but caffeine can interfere with the quality of sleep leading to sleep deprivation. Most people take beverages that contain caffeine to keep them awake during the day. But this causes less sleep time during the night. It also leads to many number of wake times during the night, making the night restless.

The next day you wake up feeling tired due to less and poor sleep. For you to feel energetic and rejuvenated, you opt for a cup of coffee. This becomes a cycle which has to be broken by limiting the amount of caffeine.


Caffeine has both positive and negative effects. It can be very effective in improving energy, alertness and concentration, but the effects can be brief if it is consumed in high doses on a daily basis. The negative effects are mainly on sleep as it reduces the quantity and quality of sleep. These effects can occur even when you are unaware. The bottom line is that caffeine should be consumed in moderation.

  • Jane
  • Updated October 30, 2016

I am Jane Collins, a Founder and a Main Editor of I decided to create this site to share my knowledge, guides and tips to help you to have a good night's sleep.

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