For many people, coping with stress and keeping a clear mind is part of an everyday struggle. Research indicates that some unpleasant behavioral and cognitive changes can result from a dehydration level of just 1 percent, a level where you may not even feel a thirst sensation. You can become mildly dehydrated from a range of activities such as not consuming enough fluids at rest, sitting on the couch, exercising or from heat.
According to recent research, headaches, increased anxiety levels and perceived difficulty of tasks, declines in working memory, vigilance, mood and concentration may all be associated with mild dehydration. Dehydration can also cause symptoms similar to those of panic such as lightheadedness and dry mouth, which can worsen your stress or anxiety levels.
In a 2011 study published in the British Journal of Nutrition, researchers found that 26 males aged 17 to 23 years old experienced impaired cognitive performance and bad moods when even mildly dehydrated. Researchers found that men who did not maintain normal body water content experienced decreased vigilance, impaired working memory, fatigue, and tension or anxiety.
In a comparative study, 25 females aged 22 to 24 also experienced similar effects to the males. When the women were mildly dehydrated, they perceived tasks to be more difficult, had difficulty concentrating as well as experienced degraded mood and headache.
What’s Going On
A review study in the Journal of the American College of Nutrition states that the effects of mild dehydration on your brain are due to an imbalance of homeostasis in your body. After all, your body is 55 to 75 percent water. The author of this review also states that the effects of mild dehydration on your memory and executive functioning are not likely as severe as the short-term, especially if the dehydration is exercise-induced. So do not worry about sweating during your workouts as long as you bring a water bottle and stay hydrated during exercise.
More research, however, is warranted on the long-term effects of mild dehydration. Nevertheless, being in a grouchy mood, having a headache, fatigue, and making mistakes while trying to get work done may very well lead to long-term negative outcomes in your work and personal life. So rule out these symptoms and keep hydrated at all times, both during and outside of exercise.
What You Can Do
So how much water should you consume to maintain a good mood and efficient work output? While the Institute of Medicine set the Adequate Intake for fluid at about 11.5 cups for females and 15.5 cups for males, fluid intake for the day varies from person to person depending on several factors. These factors including your weight, physical activity level, and health condition.
Most people's fluid requirement depends on how many calories they burn and, according to the National Research Council, most people need 1 milliliter of water per 1 calorie burned. So, if you burn 1500 calories at rest and then exercise and burn another 500 calories, you have burned a total of 2,000 calories. This equates to 2,000 milliliters of fluid per day which is 2 liters or about 8.5 cups.
If you want to prevent dehydration without thinking about calories, simply consume the IOM's recommendation of 11.5 cups of fluid daily if you are female or 15.5 cups if you are male. Remember, there is fluid in the foods you eat as well. Always speak with your dietitian if you are unsure of how much fluid to consume daily or seek further medical help if your symptoms do not subside.
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3. Ganio, M.S., Armstrong, L.E., Casa, D.J., McDermott, B.P., Lee, E.C., Yamamoto, L.M., ... Lieberman, H.R. (2011). Mild dehydration impairs cognitive performance and mood of men. The British Journal of Nutrition, 106, 1535-1543. doi:10.1017/S0007114511002005. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/21736786
4. Armstrong, L.E., Ganio, M.S., Casa, D.J., Lee, E.C., McDermott, B.P., Klau, J.F., ... Lieberman, H.R. (2011). Mild Dehydration Affects Mood in Healthy Young Women. The Journal of Nutrition, 142, 382-388. doi:10.3945/jn.111.142000. Retreived from http://jn.nutrition.org/content/142/2/382.long
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6. Fluid Needs. Clemson University Cooperative Extension. Retrieved from http://www.clemson.edu/extension/hgic/food/nutrition/nutrition/special_needs/hgic4151.html
7. Dietary Reference Intakes : Electrolytes and Water. Institute of Medicine. Retrieved from http://www.iom.edu/Global/News%20Announcements/~/media/442A08B899F44DF9AAD083D86164C75B.ashx