A couple of years ago, I first heard the term "sleep hygiene". What in the world was that? It turns out that it has less to do with germs and more to do with learning good habits that promote a good night's sleep. According to the Mayo Clinic, "Sleeping less than seven hours a night is associated with weight gain, diabetes, high blood pressure and depression, among other health risks."
A good night's sleep is a precious and wonderful thing, especially as we get older. At best, the normal stresses of life disrupt sleep. At worst, there are any number of sleep disorders that require medical care. Why does this matter to a personal trainer? Because if a client is seriously sleep-deprived, but insists on pushing through that training session, her body is going to work at cross-purposes with her need to heal, recover, reach an healthy weight, and get stronger! My clients know to cancel at times like this. Occasionally, I have done the cancelling when they are too fatigued to do it for themselves.
Someone may brag about getting by on a few hours, but in the long run, 7-8 hours per night is needed. Maximize your brain and body every day. Plan and prepare for sleep!