Sleep has great health benefits, but how much is too much? According to Dr. Chris Winter, a neurologist and sleep expert, it’s not an easy question to answer. The ideal sleep amount is flexible, much like diet or exercise. However, for most adults, more than 11 or 12 hours of sleep raises concerns about sleep quality. While not getting enough sleep is harmful, too much sleep can also cause issues like grogginess, or sleep inertia. The CDC suggests adults aim for 7 to 9 hours of sleep each night.