Waking up during the light sleep phase results in feeling less tired. However, exceeding 30 minutes of nap time may lead to deep sleep, where blood pressure drops, heart rate slows, and metabolism decelerates. Waking up during this phase can cause dizziness and increased tiredness, explaining why some individuals feel more fatigued after extended afternoon naps.
Additionally, research suggests that napping for over 1 hour may increase the risk of Alzheimer's disease, type 2 diabetes, and cardiovascular diseases.
