I always ask people in the sleep clinic how much caffeine they take in. Not just cups of tea and coffee. It can be caffeinated soft drinks and also chocolate. We know that caffeine stays in your body for several hours. Four to six hours after you have a cup of coffee your body has removed half of it. So if you have a strong cup of coffee within a few hours of bedtime, the effects will still be in your system. And it's a stimulant. It tends to make you feel more alert. That's often why people are using it. But that means it's a bad idea late in the afternoon or soon before bedtime. If you're having trouble sleeping it might be worth adding up how many caffeinated drinks you're taking in during the day.