5 hours of sleep is not really healthy but it's not that harmful either and sometimes I only get 5 hours of sleep myself and I've been okay.
It's best though to aim for getting 8 to 10 hours of sleep minimum to feel fully rested and to protect your health.
Sleep is an important part of our bodies to maintain our health and with too little sleep we won't feel good and our health could be harmed as a result.