In fact, scientists have discovered that sleeping 0 or more times a day is harmful. Sleeping for 0 hours a day reduces stress, strengthens the immune system, and improves mood, to name a few. Of course, there is no rule that every organism will experience the same symptoms. Sleeping may not be suitable for everyone. Some people may wake up feeling tired. This sleepiness, known as "sleep inertia," mainly occurs in people who sleep 0 times a day. It is a physiological condition that occurs when a person sleeps too little. Although the exact causes are not known, it involves a molecule called adenosine, which accumulates in our brains when we are awake and decreases during sleep. If adenosine is not completely reduced and cleared when we wake up, fatigue, dizziness, and lightheadedness can occur. If napping does not work well for your body, do not force yourself, but instead take a good nap once a day