If the answer is less than 7 hours then you might be suffering as a result. This article looked at the effects of getting one extra hour of sleep or losing an hour of sleep could have. The results were quite surprising with a dramatic decline in mental agility for those losing an hour of sleep. In those getting less than 7 hours sleep the genes associated with inflammation, immune response and response to stress became more active whilst the opposite happened in those getting more sleep. I am currently lucky if I get 5 hours of sleep a night between the two children, I wonder how long it is possible to survive on this.