The  Influence  of  Hydration  on  Mood  

Written  By:  William  M.  Adams,  MS,  ATC  and  Douglas  J.  Casa,  PhD,  ATC  

Summary  of  Findings  • Scientific  Definition:  For  the  purposes  of  this  review  we  will  define  mood  as  the  

psychological  and  emotional  states  that  involve  tension/anxiety,  depression/dejection,  anger/hostility,  vigor/activity,  fatigue/inertia,  and  confusion/bewilderment.  Total  mood  disturbance  is  defined  as  the  estimate  of  overall  affective  state  that  is  estimated  from  the  above  six  subscales.  

• Hydration  status  has  been  shown  to  adversely  affect  mood  with  increasing  levels  of  dehydration  and  has  been  seen  with  levels  of  dehydration  as  low  at  1.3-­‐1.5%.1–5    

• Both  men  and  women  have  been  shown  to  experience  disturbances  in  mood  during  both  rest  and  exercise  while  mildly  dehydrated.  Comparatively,  women  seem  to  be  affected  more  by  dehydration  than  men  in  regards  to  total  mood  disturbance.1,2  

• Total  mood  disturbance  increases  with  increasing  levels  of  dehydration  and  has  been  shown  to  increase  with  increasing  impairments  in  cognition.7  

• Dehydration  can  act  as  an  additive  factor  to  increased  total  mood  disturbance  when  other  factors  (environmental  stress,  sleep  loss,  increased  workload,  and  impaired  nutritional  status)  are  involved.  8,9  

• Exposing  soldiers  to  the  stress  of  simulated  combat  has  deleterious  effects  on  mood,  especially  with  increased  percent  of  body  mass  loss  that  occurs  during  dehydration.10  

   

References  1.  Armstrong  LE,  Ganio  MS,  Casa  DJ,  et  al.  Mild  dehydration  affects  mood  in  healthy  young  women.  J.  Nutr.  2012;142(2):382–388.  2.  Ganio  MS,  Armstrong  LE,  Casa  DJ,  et  al.  Mild  dehydration  impairs  cognitive  performance  and  mood  of  men.  Br.  J.  Nutr.  2011;106(10):1535–1543.  3.  Lieberman  HR,  Castellani  JW,  Young  AJ.  Cognitive  function  and  mood  during  acute  cold  stress  after  extended  military  training  and  recovery.  Aviat  Space  Environ  Med.  2009;80(7):629–636.  4.  Gopinathan  PM,  Pichan  G,  Sharma  VM.  Role  of  Dehydration  in  Heat  Stress-­‐Induced  Variations  in  Mental  Performance.  Archives  of  Environmental  Health:  An  International  Journal.  1988;43(1):15–17.  5.  D’anci  KE,  Vibhakar  A,  Kanter  JH,  Mahoney  CR,  Taylor  HA.  Voluntary  dehydration  and  cognitive  performance  in  trained  college  athletes.  Percept  Mot  Skills.  2009;109(1):251–269.  6.  Ely  BR,  Sollanek  KJ,  Cheuvront  SN,  Lieberman  HR,  Kenefick  RW.  Hypohydration  and  acute  thermal  stress  affect  mood  state  but  not  cognition  or  dynamic  postural  balance.  Eur.  J.  Appl.  Physiol.  2012.  7.  Lieberman  HR,  Bathalon  GP,  Falco  CM,  Kramer  FM,  Morgan  CA  3rd,  Niro  P.  Severe  decrements  in  cognition  function  and  mood  induced  by  sleep  loss,  heat,  dehydration,  and  undernutrition  during  simulated  combat.  Biol.  Psychiatry.  2005;57(4):422–429.  8.  Moore  HG,  Galloway  JL.  We  Were  Soldiers  Once...and  Young:  Ia  Drang  -­‐  the  Battle  That  Changed  the  War  in  Vietnam.  Random  House  Digital,  Inc.  2004.  9.  Meyerhoff  J,  Hebert  M,  Huhman  K,  Mougey  E,  Oleshansky  M,  Potegal  M.  Operational  stress  and  combat  stress  reaction:  Neurobiological  approaches  toward  improving  assessment  of  risk  and  enhancing  intervention.  In:  Friedl  K,  Lieberman  H,  Ryan  D,  Bray,  eds.  Countermeasures  for  Battlefield  Stressors.  Baton  Rouge,  LA:  Louisiana  State  University  Press;  2000:27–87.  10.  Lieberman  HR,  Tharion  WJ,  Shukitt-­‐Hale  B,  Speckman  KL,  Tulley  R.  Effects  of  caffeine,  sleep  loss,  and  stress  on  cognitive  performance  and  mood  during  U.S.  Navy  SEAL  training.  Sea-­‐Air-­‐Land.  Psychopharmacology  (Berl.).  2002;164(3):250–261.      

Practical  Applications  • Maintaining  an  appropriate  level  of  hydration  is  essential  in  preventing  an  increase  in  

total  mood  disturbance.  • Since  mood  and  cognitive  function  are  interrelated,  maintaining  a  euhydrated  state  will  

ensure  optimum  levels  of  cognitive  processing  and  associated  mood.  • Since  dehydration  has  been  shown  to  affect  mood  during  both  rest  and  exercise,  it  is  

recommended  that  one  maintain  an  appropriate  level  of  hydration  throughout  the  day.  

Looking  Ahead  • While  evidence  shows  that  total  mood  disturbance  is  affected  by  dehydration,  there  

have  been  no  studies  done  to  date  looking  at  changes  in  mood  with  increasing  levels  of  dehydration  over  time.  

• Future  research  looking  at  soldiers  in  the  military  to  identify  the  magnitude  effect  that  hydration  has  on  mood  disturbance  when  soldiers  experience  multiple  stressors  at  once  (during  a  combat  simulation  for  example).  

• Additional  research  looking  at  military  soldiers  to  see  how  real  combat  situations  may  affect  mood,  especially  when  they  are  in  situations  where  appropriate  hydration  is  impossible  to  maintain.  

The  Profile  of  Mood  States  (shown  left  in  abbreviated  form)  is  one  of  the  valid  tools  that  are  used  to  assess  mood.  It  is  comprised  of  65  items  that  asks  the  participant  to  rate  their  feelings  based  on  the  words  provided.