The reality is that constant sleep deprivation is pretty much the best way to ensure poor performance at the gym. When you're sleep-deprived, your coordination, endurance, and perceived exertion all suffer, making exercise feel more challenging, while opening yourself up to the potential for injuries. Being sleep-deprived also whacks out your hormones, making you more likely to overeat during the day while reducing energy expenditure (burning fewer calories). Which, together, is pretty much the blueprint for weight gain.
Sleep is your body's opportunity to rest, repair, and recover from everything you throw at it. Consistently failing to get enough sleep pretty much guarantees your entire life will suffer, even if you're loathe to admit it. Darin Hulslander, a certified strength and conditioning specialist and nutritionist, says, "Sleep provides mental, hormonal, psychological, and physical recovery. It isn't just a physical need; it's physical, hormonal, and neurological."
In other words, you could actually be a better athlete and a better human being if you just let yourself have another hour or two of rest in the morning.