There is something significant about 3. There are the survival rules of 3. You can die in: 3 seconds without thinking/reacting. 3 minutes without breathing. 3 hours without warmth. 3 days without water. 3 weeks without food.
And here is another, a third of each day. You have always heard that 8 hours is the amount of sleep needed. That is a third of a 24 hour day. Repeatedly going without that third of a day in sleep leads to deprivation. Mental acuity and capability declines. It has caused accidents like Exxon Valdez oil spill and auto accidents. Causes forgetfulness and depression. It impairs judgement, attention, alertness, concentration, reasoning, problem solving and retention. Doubles the risk of heart disease, failure, attack, irregular beat, high blood pressure. Leads to lackluster skin, fine lines, dark circles / puffiness under the eyes, and weight gain.
So cutting sleep by about a third, meaning 5 to 6 hours of sleep, will lead to the above.
Less sleep is not a badge of honor. It is a recipe for failure and disaster.