A New Year’s resolution idea: just add water

I sat down two days ago with some ambition to write a blog post (or two). In the end I did not write a word. Why? As I explained to my girlfriend, ‘my brain wasn’t working’. Try as I might, I found the whole idea of writing anything cogent too much. I did a quick scan of things that might have caused this state. I was not short on sleep. Neither had I eaten any wheat (I’ve found from experience this tends to turn my brain off).

Then I wondered if I might be dehydrated. It was about 4.00 in the afternoon, and I could only remember passing water twice all day – not a good sign. Plus, there was no doubt in my mind that I had drunk only a small proportion of the water I would normally consume when, say, in my own home. I stepped up my water intake and felt quite quickly revived. It might have been a placebo response, but maybe not.

This morning I decided to see if there was any recent evidence on the impact of dehydration on mental functioning, and did indeed come across a relevant study [1]. In this research, 25 women were subjected to a variety of assessments of mood, mental functioning and wellbeing in a normally hydrated state, as well as a dehydrated state. On one occasion, dehydration was induced with intermittent exercise but not heat. On another occasion, dehydration was induced not just with exercise, but by administration of the diuretic drug frusemide (furosemide).

Overall, dehydration with or without frusemide led to an average of 1.36 per cent of body mass. Just to put this into perspective, for someone weighing 70 kg, this would equate to about 1 kg (or 1 litre) of dehydration. In other words, this extent of dehydration would be described as ‘mild’.

At this level of dehydration, basic cognitive (brain) function was not significantly affected. But other functions were, including the amount of perceived effort used by women to complete a task. My experience yesterday meant that I could totally relate to this.

In addition, the concentration and mood of the women were also adversely affected. The women were more fatigued too, and were more prone to headaches. All this, remember, was the result of relatively mild dehydration.

None of this actually proves my inertia yesterday was caused by something as simple and rectifiable as dehydration, but it is at least consistent with it. I’d say as far a New Year resolutions go, many of us could do a lot worse than just to ensure we’re decently hydrated. How much should we drink? I suggest enough to ensure our urine stays pale yellow in colour throughout the day.


1. Armstrong LE, et al. Mild Dehydration Affects Mood in Healthy Young Women J Nutr January 1, 2012 jn.111.142000

7 Responses to A New Year’s resolution idea: just add water

  1. John Walker 30 December 2011 at 11:17 pm #

    OK Dr. Briffa…

    After the Holidays are over though!

    (I count the water I use to make tea and coffee as part of my daily requirement of water and I haven’t drunk much of either lately.) Mind you, beer is 90% water, so maybe I had my fill this last week. I jest of course. In fact I am feeling “brain-fagged” too, and my writing has suffered because of it. You could have something. I’ll just go and refill my filter jug!

    Thanks and a Good New Year to you.


  2. Angie from allaboutparasites.com 2 January 2012 at 10:26 am #

    Dr. Briffa, this is just the type of new year’s resolution that I can wholeheartedly support. I’m going to present this very same idea of drinking more water as an easy resolution to keep that will make a real difference in our lives to my own readers in my January newsletter. So many times it’s the little things that have the most impact. Thanks for the simple but timely reminder.

    Blessings for the new year,

  3. Sandy Halliday 2 January 2012 at 2:40 pm #

    Although not a scientific study, I remember reading an article few years ago about a “Water Club” that was introduced in a care home for the elderly. The staff encouraged the residents to drink between 8 and 10 glasses of water a day.

    The manager reported that the results were “fantastic”, and that the “whole home buzzes now; there isn’t that period after lunch when everyone goes off to sleep”.

  4. Ajana 3 January 2012 at 8:46 am #

    If I don’t drink enough water during the day, I am awoken from my sleep with a raging headache! I call it my dehydration dinger.

  5. Penny Graham-Jones 3 January 2012 at 12:01 pm #

    This is such a good reminder. It’s so easy to forget to drink until you feel really thirsty, and then of course you’ve left it far too long!

  6. George Super BootCamps 5 January 2012 at 1:02 am #

    This is exactly the sort of anecdotal evidence that the general public really needs to hear; without prominent health experts telling the crowd what their personal and professional experiences and opinions are they stand no chance of getting themselves out of the obese, unhealthy and unfit malaise that they find themselves in. That’s the reason I write my blog, to help others educate themselves effectively and give them options for creating and living a healthy and enjoyable life.

    I find your work a breath of fresh air.

    Keep up the good work,
    George superbootcamps

  7. Ryan 5 January 2012 at 1:51 am #

    And this is what I talk to all drink water water is our best friend for overweight…

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