Firstly, if you’re napping at the wrong times, it may actually be disrupting your sleep schedule, making it harder for you to fall asleep at night. “This can lead to sleep deprivation, which can cause fatigue and feelings of sickness,” says Seeley.

According to the Sleep Foundation, experts typically recommend that adults take naps eight or more hours before bedtime. For most people, that means napping before 3 p.m.

You may also be sleeping for too long – known as sleep inertia – which can cause feelings of sickness, dizziness, and headache. Researchers often suggest that a 20 minute nap is the best length, as it allows your mind and body to rest without entering the deeper stages of sleep.

Seeley also warns that sleeping in a poor environment, like somewhere noisy or uncomfortable, can disrupt your sleep quality and cause feelings of sickness.

Finally, certain health conditions, such as sleep apnea, can cause feelings of sickness after napping. “It’s important to speak with a healthcare professional if you experience persistent feelings of sickness after napping,” Seeley adds. “Having a good nap can help boost your energy levels and productivity throughout the day.”

A sleep expert explains why naps might be making you feel sick – and how to overcome it