A lack of sleep won't kill you they always say. I beg to differ. Lack of sleep is very toxic for the body as I document in many other links.
However, realism demand the observation that modern life sometimes requires us to go for short periods of time without much sleep. A sick child, a big school project - any number of things can significantly reduce our pillow time. Below I show you how to, as best one can anyway, survive the experience without too much physical damage.
Of course, please don't consider this an endorsement to go with low sleep for an extended period of time - that is bound to degrade your long term health. It is like trying to plug the holes in a collapsing dam: you can do it for awhile but eventually the flood is going to bury you.
Here is what you can do, though, to survive it in the short term:
1) Vitamin C. Take around 2-3 grams of Vitamin C per day, always with little to no fat in your stomach. Vitamin C lowers cortisol and decreases stress reactivity and lack of sleep usually significantly raises cortisol. Cortisol will make you fat, crowd out your testosterone and rip apart your neurons. (Other than that, it's great though...)
2) Apple Juice. Your memory will start to suffer with sleep deprivation and apple juice can help (according to a number of animal studies) by boosting acetlycholine, the memory transmitter. I recommend my Brain Diet as well for additional protection as cortisol is very hard on the brain - you need all the protection you can get.
3) Caffeine. Remember our motto during times like these: "It's never too late to caffeinate". Caffeine is important during sleep deprivation, because your hunger will be shooting through the roof in spite of the fact that your body's need for calories is no greater. My preferred forms of caffeine delivery are black (ice) tea and black (iced) coffee. I recommend no sugar and little fat - these are simply too much temptation during times of low sleep.
4) Exercise. Lack of sleep induces almost instant blood sugar problems. That's why it's absolutely critical to exercise when you have lost sleep. You don't have to spend a lot of time - a few shorter times throughout the day are better - but don't skip it. High blood sugar and insulin lead to a host of problems and accelerates tissue aging through the body.
5) HIIT. If you can do a little bit of Interval (HIIT) training to boost growth hormone, this would be ideal. Lack of sleep can lower growth hormone and this will at least give you a few multihour boosts during the daytime.
6) Supplementation. There are a few supplement which can bolster your immunity that should be taken daily: Vitamin D and zinc. Take about 1600 IU of Vitamin D and 50-100% of the RDA for zinc. This with the Vitamin C will help your embattled immunity.
What about testosterone? Unfortunately, I don't have a solution for the drop in testosterone that you'll experience (unless you're on HRT of course). However, sleep apnea only downs testosterone by about 30-40%. Whatever you do to yourself cannot possibly hurt your testosterone more than waking up hundreds of times per night like the typical apnea sufferer experiences. Guys can handle a little lower testosterone generally for a short period of time - just don't let it go on too long!
NOTE: References for the above are contained in other links. Just use the Search above if you're interested.