In a recent study, minor dehydration (about 1-2% below optimal levels) was a factor in headaches, energy levels, stress levels, mood and cognitive function. For more on the study, see: http://healthland.time.com/2012/01/19/bad-mood-low-energy-there-might-be-a-simple-explanation/ What is most striking about this study is that the women were mildly — not severely – dehydrated. Their water…