I'm productive on six hours of sleep in the sense that I get something done. However, I am quite noticeably less productive than if I get more sleep.
Even if I don't feel tired, I notice that my thoughts are more muddled and it's hard to concentrate. If I get 6 hours or less of sleep one night, it's usually not a problem. But if the lack of sleep is over multiple days (like it usually is), then it becomes much worse.
Even if I don't feel tired, I notice that my thoughts are more muddled and it's hard to concentrate. If I get 6 hours or less of sleep one night, it's usually not a problem. But if the lack of sleep is over multiple days (like it usually is), then it becomes much worse.