Feeling tired and sleepy after having coffee: Here’s why it happens and how to prevent it

Coffee is widely celebrated as a go-to energy booster, helping millions shake off morning grogginess, stay focused at work, or power through a busy day. However, for some people, coffee has the opposite effect; instead of feeling alert, they feel sluggish, tired, or even sleepy shortly after drinking it. This surprising reaction can be confusing, but it has clear scientific explanations. Factors like caffeine tolerance, adenosine rebound, blood sugar changes, and individual metabolism all play a role. Understanding these mechanisms can help people enjoy the benefits of coffee while avoiding the common post-coffee slump, making their daily cup of coffee both enjoyable and energising. 1. Adenosine rebound Coffee keeps you awake by blocking adenosine, a brain chemical that makes you