calorie restriction extends life in laboratory animals
moderation is the greek virtue which emphasizes everlasting satisfaction in life's necessary but potentially gluttonous aspects: food, sex, etc
it may also be the case that reducing sleep to maintain less overall dependence on sleep may have some similar affect.
the idea of hormesis using low level stressors is beyond scientifically valid it is everywhere as a method to make things stronger think lifting weights, wind current to strengthen the stocks of plants and "whatever doesn't kill you makes you stronger" some have even suggested that antioxidants are actually toxins which turn on immune defenses and strengthen the body through hormesis (low level stressor) rather than a direct protective mechanism.
if hormesis applies to sleep then a low level stressor of less sleep will make you stronger and over sleeping will make you weaker.
without even considering hormesis too much sleep per day could just make you feel lazy because your spending less waking hours actively alive and newtown's inertia principle is all about how an object in motion tends to stay in motion too much sleep may reduce your daily momentum your inertia too little sleep could probably do the same.
if it is hormesis you would build up to it like weights sleep is pretty essential though and if your already doing a lot to stress out the body adding sleep deprivation to that level of stress may be counterproductive
however if you are adapted to your workout routine stress levels are steady and your doing good and you want to try and get a little edge cut out two hours of sleep and stay like this for a month see how you feel then come back here ask the question again do some research and keep a journal log post your results around keep it simple and good luck !