Motivation and emotion/Book/2014/Dehydration and mood

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Dehydration and mood:
What are the effects of dehydration on mood?
Figure 1. A glass of water

Overview[edit | edit source]

This chapter will demonstrate the effect dehydration has on mood and why it is important to stay hydrated to ensure optimal mood to improve your life and stay healthy. As you read through the chapter be sure to check your understanding by following the learning outcomes above. Hopefully, by the end of the chapter you are able to distinguish the relationship between dehydration and mood and feel inspired to maintain a happy and healthy lifestyle using the practical tips provided in the chapter to avoid dehydration and its effects on mood. To begin the chapter take the quiz below to find out whether you are dehydrated.

Learning outcomes[edit | edit source]

  • What is dehydration?
  • What are the effects of dehydration on mood?
  • Why is it important to stay hydrated?
  • What can you do to optimise mood and avoid dehydration?

Quiz: Are you dehydrated?[edit | edit source]

1 Does your mouth feel dry and sticky?

A – Yes, quite often.
B - Sometimes.
C - No.

2 Do you often get headaches?

A - Yes, quite often.
B - Sometimes.
C - No.

3 Have you noticed a lack of urination?

A - Yes, quite often.
B - Rarely.
C - No.

4 Do you have dry skin?

A - Yes, quite often.
B - Sometimes.
C - No.

5 Are you feeling;

A - Tired?
B - Angry?
C - Average?

If you answered mostly 'A', there is a high chance that your body is dehydrated and in need of fluid which in turn can be causing increased fatigue, read on to learn more about why you are currently, or have recently experienced these symptoms in order to prevent this in the future. If you answered mostly 'B' your body may possibly be dehydrated if you have not been consuming adequate amounts of fluid recently, or symptoms may be occurring due to an alternative explanation and you may need to seek medical advice if symptoms continue. If you answered mostly 'C' is it likely your body is receiving adequate water supply enabling it to produce enough water around your body preventing dry skin, lack of urination, a dry, sticky mouth, preventing the uncomfortable tension caused by a headache due to dehydration, as well as negative moods, Well done!

Understanding dehydration[edit | edit source]

Two-thirds of our bodies are made up of water. Humans are known to survive only three to five days without any fluid intake (Benton, 2011), therefore it is essential for our survival. Interestingly, as far back as the time when primeval species began walking the earth the major goal in order to survive has been preventing dehydration (Popkin, D’Anci & Rosenberg, 2010). Dehydration occurs when 1% or higher of body mass drops due to fluid loss. A loss of 2% or higher can lead to significant implications such as impaired cognitive function, decreases in physical performance, headaches and serious mood alterations. When a person has suffered mild dehydration (i.e. a loss of 1-2% body mass) over a specific period of time they are at risk of severe conditions such as a urinary tract infection and constipation (Gibson-Moore, 2013). In other words, dehydration occurs when a person’s total body water level falls below normal in which there is a greater loss of fluid than what is being taken in (Hope, 2013). Interestingly though, thirst is not triggered until our water volume falls by about 2% when mild dehydration has already set in at approximately 1-2% loss of water and our moods are already being affected (Gibson-Moore, 2013). There are many ways in which our bodies naturally loose water including exercise, sweat, breathing, urine, and defacing, vomiting and diarrhoea also cause a loss of water from our bodies. In contrast we receive water supply from drinking and eating (Komaroff, 2006). Approximately 20% of water intake comes from food intake while beverages of all kinds provide the other 80% (Goldman, 2011). Dehydration can start of mild with symptoms such as dizziness when standing up, fatigue and weakness and become more severe resulting in dangerously low blood pressure and even loss of consciousness (Komaroff, 2006). Other symptoms of dehydration include a dry, sticky mouth, thirst, fatigue, dry skin, headaches, dizziness, muscle weakness, little urination and a fever just to name a few (Jéquier & Constant, 2010).Dehydration is also said to effect mood in which will be explored throughout the chapter.

Dehydration and mood[edit | edit source]

Understanding moods[edit | edit source]

Reeve (2009) explains mood as an aftereffect feeling of a previously experienced emotional episode. There are two types of moods including Positive mood and Negative mood, usually described in psychology as positive affect and negative affect. Positive affect is a person's level of enthusiasm and pleasure, when a person feels high positive affect they feel energized, alert and optimistic. In contrast, a negative affect is felt when a person experiences feelings of dissatisfaction and irritability. It is important to realise that moods are actually not the same as emotions. To learn more about the differences and similarities between mood and emotion go to the chapter Mood and emotion

Dehydration effects on mood in men[edit | edit source]

Ganio et al. (2011) conducted a study to access the effects of dehydration on mood in young males. Twenty-sex men participated in trials of exercise-induced dehydration where assessments were conducted on mood and cognitive performance. Moods were assessed using the profile of mood states (POMS) questionnaire which has the ability to detect any change in serotonergic function where it has been suggested that changes in this neurotransmitter are strongly associated with adverse effects of dehydration. The POMS questionnaire is a widely used tool which is a standardized register of mood states. The questionnaire involves a series of sixty-five mood-related describing words which participants rate on a 5-point scale in response to the question “how are you feeling right now?” the words are separated into sub-scales including tension/anxiety, depression/dejection, anger/hostility, vigour/activity, fatigue/inertia and confusion/ bewilderment. The experiment found that during rest from exercises the mood state of the men was adversely affected, in particular tension/anxiety and fatigue/inertia increasing even though there were no detectable changes in symptoms such as headache or perceived task difficulty. Interestingly, mood state was the first to be effected due to mild dehydration. Unfortunately, although mood states were adversely affected by dehydration the brain mechanism that is in control of the deterioration in mood states due to dehydration remains unknown.

Dehydration effects on mood in women[edit | edit source]

Armstrong et al. (2012) conducted a study similar to Ganio et al. (2011) that produced mild dehydration through intermittent moderate exercise in order to investigate the effects of dehydration on cognitive performance and mood. Mood as well as cognitive performance and symptoms of dehydration were assessed during the experiment and at rest. It was found that dehydration does in fact have adverse effects on mood in females, consistent with previous research conducted on males[factual?]. Profile of mood states (POMS) questionnaires were used to assess the women’s moods. The volunteers had to rate a series of 65 mood-related describing words on a five-point scale in response to the question “how are you feeling right now?” [grammar?] the six sub scales were tension-anxiety, depression-dejection, anger-hostility, vigour-activity, fatigue-inertia, and confusion-bewilderment. The results gathered from the POMS questionnaires of the women during treadmill exercise and at rest found that when the women were dehydrated (mean loss of 1.36% body mass) vigour and fatigue were adversely affected. Like Ganio et al. (2011), Armstrong et al. (2012) also mentions that although studies have found that dehydration in both women and men have adverse effects on mood the physiological mechanism underlying the associations between dehydration and mood remain unknown. In summary, the present study found that mild dehydration has adverse effects on mood states such as vigour and fatigue in females[factual?].

Gender differences[edit | edit source]

In conclusion from studies conducted by both Ganio et al. (2011) and Armstrong et al. (2012) it was found that there is a significant difference in mood states of dehydrated females than dehydrated males, both at rest and during exercise, where females reported more adverse effects on mood than did males. Ganio et al. (2011) explained that findings from the study conducted with men only are comparable with similar studies conducted on women. Both Ganio et al. (2011) and Armstrong et al. (2012) experiments produce near exact levels of dehydration[grammar?]; 1.39% body weight loss for men and 1.36% body weight loss for women. Experimental conditions were similar using the same exercise regimen within similar environments and the same questionnaire was used to assess mood states (POMS) in both studies. Adverse effects of dehydration on mood were substantially more significant in females than males. Adverse changes in fatigue/inertia and tension/anxiety were evident in males and females mood states of confusion/bewilderment, vigour/activity as well as their total mood disturbance worsened during rest and exercise. One possible explanation of the significant difference in altered moods of women due to dehydration may be due to women’s menstrual cycle. It was found that during menstrual cycles females are likely to be affected by modest levels of dehydration in which disrupts fluid balance and alters mood, which has been supported by Armstrong et al. (2012).

How dehydration affects our mood[edit | edit source]

Many studies have been conducted to find out how dehydration affects mood, similar to the above studies on women and men by Ganio et al. (2011) and Armstrong et al. (2012). According to Gibson-Moore (2013) and many other researchers dehydration has adverse effects on mood, in particularly [grammar?] increasing feelings of aggression and/or irritation, and fatigue. A study conducted by Pross (2012) also found that dehydration affects several mood aspects including fatigue, sleepiness and lowered alertness. Subjects in the study were also more confused, less calm and unhappy. After mood was assessed, mood impairments induced by dehydration were reversed by water intake except for fatigue, vigour and calmness. Pross (2012) study was said to be the first to find long term effects of dehydration on mood that were not able to be reversed by water intake. Interestingly it was found that mood impairments due to dehydration were observed early in the study after wakening from sleep with 12-16 hours of no fluid intake.

Physiological explanation[edit | edit source]

Armstrong et al. (2012) suggests that when initial physiological indicators of dehydration appear it is detected by hypothalamic neurons which may in fact send signals to higher-order cortical regions of the brain regulating mood which then results in adverse mood. Ganio et al. (2011) explains that, unfortunately, although mood states were adversely affected by dehydration, the brain mechanism that is in control of the deterioration in mood states due to dehydration remains unknown. Ganio et al. (2011), like Armstrong et al. (2012) suggests that because accurate regulation of electrolyte balance is vital for chemical and electrical neurotransmission, changes in the balance of electrolytes may affect higher-order brain areas. Ganio et al. (2011) explains that another explanation may be that the neurotransmitter, serotonin, which is a critical aspect of regulating some behaviour, is altered by dehydration which in turn may mediate the effects of dehydration.

Biological explanation[edit | edit source]

Armstrong et al. (2012) had also suggested that because dehydration was induced by thermal stress the front parietal blood oxygen level-dependent response was changed which in turn could have led to the adverse changes in mood to act as a signal that evolved to alert humans before more serious consequences occurred, including degradation in performance. If adverse effects on mood were not a signal of alertness degraded cognitive or physical performance may in turn affect chances of survival where the ability to seek out water or react towards a threat would be significantly diminished.

Case illustration[edit | edit source]

Kate leads a very busy lifestyle, [grammar?] last night she was so tired she went straight to bed without Dinner. In the morning Kate woke up and noticed her mouth felt dry and sticky. She remembered she has a friends party on at 12 pm and jumped out of bed excited for what was going to be a good day and felt like nothing could ruin her day, however she quickly had to sit back on the edge of her bed as she was feeling dizzy and light headed. She could feel a headache starting to throb behind her forehead. Kate recovers from her dizzy spell and walks out into the kitchen to find her sister had eaten all the fruit loops. Kate's elevated mood begins to deteriorate and she starts to feel irritable and annoyed. To get revenge on her Sister Kate decides to drink all of her Sisters favourite milk. Feeling good about herself Kate goes about her day. Kate's irritable mood decreases and she is feeling excited about her day again.

According to a study conducted by D'anci et al. (2009) it was found that mood is particularly sensitive to a person's hydration state. The above case-illustration demonstrates how dehydration status can affect our moods. By the sounds of Kate's busy schedule it is likely she had not consumed adequate water intake over a period of at least 12 hours as she skipped dinner and was fasting during her sleep cycle. When Kate awoke the following morning she was showing signs of dehydration including a dry and sticky mouth, dizziness and a headache. Kate's mood was soon adversely effected by her dehydration status as she began feeling irritable. As Pross (2012) mentions mood impairments resulting from dehydration were easily reserved by fluid intake. This explains why Kate's mood elevated shortly after drinking her Sisters [grammar?] favourite milk in which Kate believed her mood elevated because she got 'revenge' however the increase in positive mood is likely to be a result of rehydration.

Figure 3. A tap dripping. Are you thirsty?


The importance of hydration[edit | edit source]

After reading through the research conducted on dehydration and its effects on mood as well as health, answering the question ‘why is it important to stay hydrated?’ should be relatively simple. As the theme of this chapter suggests it is important to stay hydrated to ensure optimal mood as well as health in order to live a happy, healthy life. Apart from ensuring optimal mood states through hydration, staying hydrated is also important for bodily function. Water is essential for survival therefore our bodies cannot function to the best of its ability without adequate water intake, and without any fluid intake at all our bodies will shut down in a matter of days. Water performs numerous vital roles in the body including the transportation of nutrients and waste between major organs, regulating body temperature and lubricating our joints. Water also helps with digestion and metabolism (Gibson-Moore, 2013). Read on for practical advice on how to stay hydrated.

Dehydration management[edit | edit source]

You may not realise but everyone has different needs when it comes to fluid consumption. Some populations are more at risk of dehydration than others due to factors such as age and medical condition including the elderly, children and diabetics. Diabetics, even when minimally dehydrated, can experience adverse moods (Armstrong et al., 2012). Read on to find out how to avoid dehydration. Note: Elderly and populations with a medical condition are recommended to follow the provided guidelines below with the exception they are aware that they pose a higher risk of dehydration and therefore should maintain optimal hydration at all times to avoid detrimental health effects.

Preventing dehydration in children[edit | edit source]

Studies have revealed that the number of children arriving to school dehydrated is alarmingly high, some schools showing a high percentage of 60% and above[factual?]. Children have a higher risk of dehydration than adults because they are less tolerant to heat, more physically active, have a high surface-to-body-weight ratio, limited ability to concentrate urine, little ability to express feelings of thirst and children have a high metabolic rate (Jéquier & Constant, 2010). Gibson-Moore (2013) explains that children between 2 and 18 years old should be consuming between 1.3-2.5 litres/day of water. Healthy drinking behaviours are established in childhood and therefore it is essential that children are encouraged to consume enough fluid during the day in order to stay hydrated to ensure optimum health and mood. As mentioned previously food contributes to 20% of water volume and beverages make up the other 80%, Gibson-Moore (2013) suggests that foods that contain high water content such as fruit, vegetables, yogurt, soup and stews should be provided to children. Table 1. contains helpful information on the different types of fluid that prevent dehydration to ensure optimal mood and health. This table is a guide only and contains high nutritional drinks starting at the top that should be consumed regularly descending down to drinks that should only be consumed in small portions and in moderation (Gibson-Moore, 2013).

Table 1. Healthy hydration guide for children by Gibson-Moore (2013).

Fluid Explanation
Drink plenty of Water Water is a great source of fluid to stay hydrated as it does not provide calories and does not harm the teeth.
Regularly drink milk Milk is an excellent source of calcium, proteins, B vitamins and nutrients. It is highly recommended that children should be given semi-skimmed milk and to avoid milk containing added sugar such as milkshakes and hot chocolates which should be consumed only occasionally.
Drink fruit juices in moderation fruit juices contain vitamins and minerals as well as provide water. just one serving of 100% fruit juice equals one portion of a child's 5-a-day. However fruit juice does contain sugar and can harm teeth so it is recommended to be watered down and to be consumed at meal times.
Smoothies once a day Smoothies also provide a source of water as well as vitamins and minerals. Like fruit juices, smoothies that contain 150 ml of fruit juice and 80g of fruit (pulped or crushed) equals two serves of a child's 5-a-day! however smoothies also contain sugar and should be consumed at meal time to reduce risk of harm to teeth.
Occasionally low calorie soft drinks Low calorie soft drinks do in fact provide water and without extra calories however these drinks can be harmful for the teeth as they contain acid. Some low calorie soft drinks also contain caffeine!
Just occasionally drink tea and coffee As caffeine is a stimulant high amounts should be avoided for children. it is recommended that children are given decaffeinated tea and coffee with semi-skimmed milk and avoid added sugar.

Practical tips to keep children hydrated[edit | edit source]

  • Ensure your child is sent to school with a drink bottle.
  • Encourage your child to drink fluid regularly (i.e. before, during and after school/playtime).
  • Offer your child a drink regularly particularly in hot environments and before, during and after physical activities.
  • Provide high water content foods such as fruits and vegetables.
  • Be sure to make fluids readily available such as milk and water.
  • When choosing a drink for your child, be aware of the nutritional value and provide them with a drink that won’t impact on their dental health.

By Gibson-Moore (2013)

Preventing dehydration in adults[edit | edit source]

Figure 4. "Eating a three-ounce cucumber is like drinking three ounces of water, but better," (Goldman, 2011, p.1)

According to Jéquier and Constant (2010) a sedentary adult (an adult doing little exercise and sitting down most of the time) loses 2 to 3 litres of water p/day. When considering how much water a person loses each day it depends on external factors such as air temperature, climate and humidity. It is estimated that a sedentary adult should consume between 2 to 3 litres of water per day depending on age, gender, climate and physical activity (Jéquier & Constant, 2010). In order to prevent dehydration and affected mood, adults, much like children, are encouraged to keep their fluids up during the day, even if they are engaging in little to no exercise as your body is constantly losing water, as your body loses water your mood will be effected and it is likely you will become irritable or experience other negative decreases in mood state[Rewrite to improve clarity]. To improve your life through health and happiness with a positive mood always stay hydrated. We all know how difficult it can be to consume 2-3 litres of water a day so it is recommended that along with drinking plenty of water you should also feed your body with foods high in water content and nutrients to meet your daily intake of water. Table 2. suggests fluid and foods high in nutrients, electrolytes, vitamins and water to keep hydrated and healthy.

Table 2. Foods and fluid high in water content, vitamins, electrolytes and nutrients by Goldman (2011).

Item Water source Description
1 Cantaloupe, peaches and strawberries As potassium is an electrolyte which is lost during perspiration, these fruits contain high contents of potassium and will replace lost potassium to maintain fluid levels and aid in heartbeat regulation and circulation.
2 Vitamin C - Watermelon, kiwi, citrus Per serving provides at least a third of your daily water needs plus they contain vitamin C which aids in joint flexibility.
3 Tomatoes and Broccoli Ninety percent of broccoli is actually water and contains a compound called isothiocyanates which blocks defective genes that may cause cancer. Tomatoes too can reduce risk of lung, prostate, stomach, breast, colon and cervical cancer as it contains a rich antioxidant named lycopene.
4 Beans One cup of cooked beans such as kidney and pinto equals a half a cup of water and just as much protein two eggs would provide as well as providing half your daily fibre needs
5 Plain yogurt Sweetened yogurt contains approximately four or more teaspoons of sugar whereas plain yogurt is rich in water and protein.
6 Coconut water Provides more electrolytes than sports drinks.

Practical tips for adults to stay hydrated[edit | edit source]

  • Keep a water bottle with you were ever you go (i.e. work, shopping, University).
  • Remember to drink fluid regularly even if you are not thirsty.
  • Drink regularly in hot environments and before, during and after physical activities.
  • Consume high water content foods such as fruits and vegetables.
  • Make a salad for the whole week as watermelon and kiwi stay healthy six days after being cut.
  • Avoid sports drinks and energy drinks, instead drink coconut water as it provides more electrolytes than sport drinks.

Conclusion[edit | edit source]

Upon reading this chapter, hopefully, you have gained a strong understanding of what dehydration is and how it can affect your mood. The research and practical tips provided aim to guide and encourage you to take the appropriate steps to a hydrated and happy life. Staying hydrated is not only important to ensure optimal mood but also to improve your well-being in order to live a long, happy and healthy life. There are additional external links provided at the bottom of the page to further expand your knowledge of dehydration and mood as well as a link to foods that will keep you hydrated. Be sure to return to the learning outcomes provided at the start of this chapter to check your understanding of the chapter content.

See also[edit | edit source]

References[edit | edit source]

Armstrong, L. E., Ganio, M. S., Casa, D. J., Lee, E. C., McDermott, B. P., Klau, J. F., & Lieberman, H. R. (2012). Mild dehydration affects mood in healthy young women. Journal Of Nutrition, 142(2), 382-388. Retrieved from

Benton, D. D. (2011). Dehydration influences mood and cognition: a plausible hypothesis?. Nutrients, 3(5), 555-573. Retrieved from

D'anci, K. E., Vibhakar, A., Kanter, J. H., Mahoney, C. R., & Taylor, H. A. (2009). Voluntary dehydration and cognitive performance in trained college athletes. Perceptual And Motor Skills, 109(1), 251-269. Retrieved from

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. British Journal Of Nutrition, 106(10), 1535-1543. doi:10.1017/S0007114511002005

Gibson-Moore, H. H. (2013). Improving hydration in children: A sensible guide. Nutrition Bulletin, 38(2), 236-242. doi:10.1111/nbu.12028

Goldman, L. (2011). Eat Your Water. Runner's World, 46(7), 41-43. Retrieved from

Hope, E. (2013). Sweat and hydration. NZ Rugby World, (160), 98-99. Retrieved from

Jéquier, E., & Constant, F. (2010). Water as an essential nutrient: the physiological basis of hydration. European Journal Of Clinical Nutrition, 64(2), 115-123. doi:10.1038/ejcn.2009.111

Komaroff, A. L. (2006). How can I avoid dehydration?. Harvard Health Letter, 31(9), 8. Retrieved from

McKinley, M., & Johnson, A. (2004). The physiological regulation of thirst and fluid intake. News In Physiological Sciences: An International Journal Of Physiology Produced Jointly By The International Union Of Physiological Sciences And The American Physiological Society, 191-6. Retrieved from

Pross, N. (2012). Effect of a 24-hour fluid deprivation on mood and physiological hydration markers in women. Nutrition Today, 47(4, Suppl. 1), S35-S37. Retrieved from

Reeve, J. (2009) Understanding motivation and emotion (5th ed.) USA: John Wiley & Sons Inc.

External links[edit | edit source]