According to research the 7.5 hours of sleep is better than 8 hours of sleep.
There's no requirement to actually get 8 hours of sleep unless you really need the 8 hours of sleep for yourself to function.
Most people today get only 6 to 7 hours of sleep per night and they function just fine.
Even people who get only 6 to 7 hours of sleep live a long healthy life without any health issues.
So as long as you get at least 6 hours of sleep or 7 hours of sleep then you should be just fine.
I sometimes only get 6 hours of sleep and I'm just fine however sometimes I need to get 7 or 8 hours of sleep on some nights when I'm really tired.