Sleep loss causes your performance to suffer, whether it’s on a desk job, a combat operation, or at home. Getting plenty of sleep helps you perform your best. Shortage of sleep is equivalent to being drunk. In fact, after you’re awake for 18–20 hours, your performance will be as if you had a blood-alcohol content of 0.1% (about 4 drinks for a 150-pound man) on tasks requiring eye-hand coordination, reaction time, doing two things at once, remembering important sequences, being attentive, and prioritizing what you see. You can learn some skills so well that you can still do them adequately despite being sleep-deprived, but training while you’re tired from lack of sleep won’t improve what you’re training to learn or perform.
Goel, N., Basner, M., Rao, H., & Dinges, D. F. (2013). Circadian rhythms, sleep deprivation, and human performance Chronobiology: Biological Timing in Health and Disease (pp. 155–190). doi:10.1016/b978-0-12-396971-2.00007-5