We’ve all been there: running through our hectic workday at a mile a minute, or heads down on a project that requires our undivided attention. Before we know it, it’s 4 o’clock, and we’re parched.

But by the time we realize we’re thirsty, experts say we’re already dehydrated. “Our thirst sensation doesn’t really appear until we are one or two percent dehydrated,” Lawrence E. Armstrong, Ph.D., professor of physiology at the University of Connecticut, tells UConn Today. And although dry mouth tends to be the first thing we notice, his work suggests there are other signs we may not be aware of. “By then, dehydration is already setting in and starting to impact how our mind and body perform,” he says.

Armstrong and his team at the UConn Human Performance Lab have studied the effects of mild dehydration from our everyday activities (in other words, not from exercise or exposure to heat) and identified tangible detriments to our ability to work at our best. Notably, both women and men can feel a dip in their mood and energy — and interestingly, women seem to report this more than men. “Even mild dehydration that can occur during the course of our ordinary daily activities can degrade how we are feeling — especially for women, who appear to be more susceptible to the adverse effects of low levels of dehydration than men,” Harris Lieberman, Ph.D., a research psychologist with the U.S. Army Research Institute of Environmental Medicine and one of Armstrong’s’ co-authors, adds in UConn Today.

More recently, a 2018 meta-analysis of 33 existing peer-reviewed studies on the subject, published in Medicine & Science in Sports & Exercise, found that mild everyday dehydration can take a toll on our attention span, and increases the likelihood that we’ll commit errors in our work. Melinda Millard-Stafford, Ph.D., lead study author and professor at the Georgia Institute of Technology’s School of Biological Sciences, and her team found that across the board, mild dehydration had a notable impact on participants’ performance on tasks that involve attention, such as staying focused during a long meeting. “Higher-order functions like doing math or applying logic also dropped off,” she told Georgia Tech’s Research Horizons

Filling your water bottle may be the last thing on your mind when you have deliverables to get out the door. To help keep it top of mind, try tuning into the physical signs instead — that is, how depleted or frazzled you’re feeling. Let your body’s own cues become your cue to take a sip.

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  • Mallory Stratton

    Director of Content Operations at Thrive

    Mallory is Director of Content Operations at Thrive. Prior to Thrive, she was Associate Editor on “It’s All In Your Head” by Keith Blanchard (Wicked Cow Studios, 2017), an illustrated brain science book, and worked closely on its accompanying cross-platform partnerships with Time Inc. and WebMD. She spends her off-hours curating playlists, practicing restorative yoga, and steeping new teas.