Tiredness partly genetic say researchers

Edinburgh: Genes may contribute in a small but significant way to why certain people tire easily or suffer from low energy levels. Being prone to tiredness is partly heritable, according to researchers, with genetics accounting for eight per cent of differences between people who were asked about their levels of tiredness. The large-scale study was led by Saskia Hagenaars, a PhD student at the University of Edinburgh's Centre for Cognitive Ageing and Cognitive Epidemiology and Dr Vincent Deary of Northumbria University.

Burnout and Karoshi

Author: Dr Peremarty MD: Sleep and general medicine

A syndrome at the turning point between tiredness and depression?

Burnout is a human relationship disease, close to depressive state, preceded by a heavy load of stress combined with a lot of personal frustration.
Its evolution, which remains silent over a long period, can end in suicide (in case of depression) or induce health endangering behaviours (tobacco, alcohol, drugs and medication abuse).
In Japan, Karoshi, (or Karushi - literally: death (shi) from overwork (karu) - describes a decease (no matter the cause of death itself) related to an excessive work schedule .