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Maintaining Euhydration Preserves Cognitive Performance, But Is Not Superior to Hypohydration

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Abstract

Maintaining optimal physical and cognitive performance are keys to success for most exercise contexts. However, consensus on the effects of dehydration for cognitive function is equivocal, particularly given the addition of confounding variables when hypohydration (HYPO) results. Therefore, this study aimed to examine whether maintaining euhydration (EUH) would preserve cognitive function, and whether this physiological state would be superior than if HYPO were evoked in an identical exercise task. In a crossover design, 15 participants (12 males, age 27.93 ± 6.81 years, height 177.20 ± 6.95 cm, mass 84.40 ± 12.35 kg) completed a 90 min self-paced simulated military march in the heat, whilst either maintaining EUH by consuming fluid ad libitum or becoming hypohydrated via fluid restriction. A cognitive testing battery was administered pre-exercise and following a rest period (55 ± 8 min), and evaluated information processing, memory, impulsivity, attention and concentration, and response time domains, whilst subjective estimates of performance were also quantified. Aspects of memory and impulsivity were not comparable to pre-exercise data (both P ≤ 0.05), whilst a shift in the speed-accuracy trade-off was apparent in the switching attention task, with accuracy decreasing (P = 0.003), and reaction time being supplemented (P = 0.028). Despite body mass losses of 2.28%, hydration status did not influence performance for any of the measured cognitive domains (all P > 0.05). When hypohydrated, subjective estimates of thirst were significantly greater post-exercise (P = 0.004), whilst medium effect sizes were found for lethargy (d = 0.532) and task difficulty (d = 0.553) post-exercise. Although maintaining EUH by en-large preserves cognitive function, this does not produce superior cognitive performance compared with fluid restriction following an identical exercise task. Therefore, despite losses in body mass exceeding 2%, cognitive performance remains largely stable.

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Notes

  1. Ambient temperature and humidity of the air-conditioned room where cognitive testing was completed were not obtained during the experimental testing sessions. However, recordings of ambient conditions were recorded retrospectively on five separate occasions resulting in a mean ± SD of 21.4 ± 1.7 °C, 46.2 ± 3.7% relative humidity. Although these may not reflect the exact data at the time of data collection, because temperature in the room is externally controlled via thermostat, it is likely participants completed all cognitive testing during normothermic conditions similar to these.

  2. As thirst is thought to be a confounding variable for cognitive performance (Edmonds and Burford 2009), thirst scores derived from the post-intervention VAS assessment were also included as a covariate for each ANOVA completed for cognitive performance. However, the results were not statistically different from the original analysis; thus, ANCOVA data were omitted, and only the repeated measures ANOVA data were reported.

Abbreviations

°C:

Degrees Celsius

ADF:

Australian Defence Force

cm:

Centimetre

EUH:

Euhdyration

fMRI:

Functional magnetic resonance imaging

HYPO:

Hypohydration

kg:

Kilogramme

km:

Kilometre

min:

Minute

mL:

Millilitre

mm:

Millimetre

mmol/L:

Millimoles per litre

ms:

Millisecond

RPM:

Revolutions per minute

T c :

Core temperature

USG:

Urine specific gravity

References

  • Adams, J. D., Sekiguchi, Y., Suh, H.-G., Seal, A. D., Sprong, C. A., Kirkland, T. W., & Kavouras, S. A. (2018). Dehydration impairs cycling performance, independently of thirst: A blinded study. Medicine and Science in Sports and Exercise, 50(8), 1697–1703.

    Article  PubMed  Google Scholar 

  • Adan, A. (2012). Cognitive performance and dehydration. Journal of the American College of Nutrition, 31(2), 71–78.

    Article  PubMed  Google Scholar 

  • Akerman, A. P., Tipton, C. T., Minson, C. T., & Cotter, J. D. (2016). Heat stress and dehydration in adapting to performance: Good, bad, both, or neither? Temperature, 3(3), 412–436.

    Article  Google Scholar 

  • 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. The Journal of Nutrition, 142(2), 382–388.

    Article  PubMed  Google Scholar 

  • Benton, D., & Young, H. A. (2015). Do small differences in hydration status affect mood and mental performance? Nutrition Reviews, 73(suppl 2), 83–96.

    Article  PubMed  Google Scholar 

  • Chang, Y., Labban, J. D., Gapin, J. I., & Etnier, J. L. (2012). The effects of acute exercise on cognitive performance: A meta-analysis. Brain Research, 1453, 87–101.

    Article  PubMed  Google Scholar 

  • Cheuvront, S. N., & Kenefick, R. W. (2014). Dehydration: Physiology, assessment, and performance effects. Comprehensive Physiology, 4(1), 257–285.

    Article  PubMed  Google Scholar 

  • Choma, C. W., Sforzo, G. A., & Keller, B. A. (1998). Impact of rapid weight loss on cognitive function in collegiate wrestlers. Medicine and Science in Sports and Exercise, 30(5), 746–749.

    Article  PubMed  Google Scholar 

  • Cian, C., Barraud, P. A., Melin, B., & Raphel, C. (2001). Effects of fluid ingestion on cognitive function after heat stress or exercise-induced dehydration. International Journal of Psychophysiology, 42(3), 243–251.

    Article  PubMed  Google Scholar 

  • Cohen, J. (1988). Statistical power analysis for the behavioural sciences. New York, NY: Routledge Academic.

    Google Scholar 

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

    Article  PubMed  Google Scholar 

  • Dickson, J. M., Weavers, H. M., Mitchell, N., Winter, E. M., Wilkinson, I. D., Van Beek, E. J. R., . . . Griffiths, P. D. (2005). The effects of dehydration on brain volume – Preliminary results. International Journal of Sports Medicine, 26, 481–485.

    Article  PubMed  Google Scholar 

  • Edmonds, C. J., & Burford, D. (2009). Should children drink more water? The effects of drinking water on cognition in children. Appetite, 52(3), 776–779. https://doi.org/10.1016/j.appet.2009.02.010.

    Article  PubMed  Google Scholar 

  • Edmonds, C. J., Crombie, R., Ballieux, H., Gardner, M. R., & Dawkins, L. (2013). Water consumption, not expectancies about water consumption, affects cognitive performance in adults. Appetite, 60, 148–153.

    Article  PubMed  Google Scholar 

  • Ely, B. R., Sollanek, K. J., Cheuvront, S. N., Lieberman, H. R., & Kenefick, R. W. (2013). Hypohydration and acute thermal stress affect mood state but not cognition or dynamic postural balance. European Journal of Applied Physiology, 113(4), 1027–1034.

    Article  PubMed  Google Scholar 

  • Falcone, P. H., Chih-Hao Chien, M. S., Carson, L. R., Gwinn, J. A., Mccann, T. R., Loveridge, N. J., & Moon, J. R. (2017). The effect of mild dehydration induced by heat and exercise on cognitive function. Psychology and Cognitive Sciences, 3(1), 17–23.

    Article  Google Scholar 

  • Fleming, J., & James, L. J. (2013). Repeated familiarisation with hypohydration attenuates the performance decrement caused by hypohydration during treadmill running. Applied Physiology, Nutrition, and Metabolism, 39(2), 124–129.

    Article  PubMed  Google Scholar 

  • Ganio, M. S., Armstrong, L. E., Casa, D. J., McDermott, B. P., Lee, E. C., Yamamoto, L. M., et al. (2011). Mild dehydration impairs cognitive performance and mood of men. British Journal of Nutrition, 106(10), 1535–1543.

    Article  PubMed  Google Scholar 

  • Gopinathan, P. M., Pichan, G., & Sharma, V. M. (1988). Role of dehydration in heat stress-induced variations in mental performance. Archives of Environmental Health: An International Journal, 43(1), 15–17.

    Article  Google Scholar 

  • Grego, F., Vallier, J. M., Collardeau, M., Rousseu, C., Cremieux, J., & Brisswalter, J. (2005). Influence of exercise duration and hydration status on cognitive function during prolonged cycling exercise. International Journal of Sports Medicine, 26(1), 27–33.

    Article  PubMed  Google Scholar 

  • Hancock, P. A. (1986). Sustained attention under thermal stress. Psychological Bulletin, 99(2), 263–281.

    Article  PubMed  Google Scholar 

  • Hancock, P. A., & Warm, J. S. (1989). A dynamic model of stress and sustained attention. Journal of Human Performance in Extreme Environments, 31(5), 519–537.

    Google Scholar 

  • Hocking, C., Silberstein, R. B., Man Lau, W., Stough, C., & Roberts, W. (2001). Evaluation of cognitive performance in the heat by functional brain imaging and psychometric testing. Comparative Biochemistry and Physiology, 128, 719–734.

    Article  PubMed  Google Scholar 

  • Hoffman, M. D., Snipe, R. M. J., & Costa, R. J. S. (2018). Ad libitum drinking adequately supports hydration during 2 h of running in different ambient temperatures. European Journal of Applied Physiology, 118, 2687–2697.

    Article  PubMed  Google Scholar 

  • Irwin, C., Campagnolo, N., Iudakhina, E., Cox, G. R., & Desbrow, B. (2018). Effects of acute exercise, dehydration and rehydration on cognitive function in well-trained athletes. Journal of Sports Sciences, 36(3), 247–255.

    Article  PubMed  Google Scholar 

  • Kempton, M. J., Ettinger, U., Schmechtig, A., Winter, E. M., Smith, L., McMorris, T., et al. (2009). Effects of acute dehydration on brain morphology in healthy humans. Human Brain Mapping, 30(1), 291–298.

    Article  PubMed  Google Scholar 

  • Kempton, M. J., Ettinger, U., Foster, R., Williams, S. C. R., Calvert, G. A., Hampshire, A., et al. (2011). Dehydration affects brain structure and function in healthy adolescents. Human Brain Mapping, 32(1), 71–79.

    Article  PubMed  Google Scholar 

  • Kolka, M. A., Latzka, W. A., Montain, S. J., Corr, W. P., O’Brien, K. K., & Sawka, M. N. (2003). Effectiveness of revised fluid replacement guidelines for military training in hot weather. Aviation, Space, and Environmental Medicine, 74(3), 242–246.

    PubMed  Google Scholar 

  • Lieberman, H. R. (2010). Hydration and human cognition. Nutrition Today, 45(6), S33–S36.

    Article  Google Scholar 

  • Lieberman, H. R. (2012). Methods for assessing the effects of dehydration on cognitive function. Nutrition Reviews, 70, S143–S146. https://doi.org/10.1111/j.1753-4887.2012.00524.x.

    Article  PubMed  Google Scholar 

  • Lieberman, H. R., Bathalon, G. P., Falco, C. M., Kramer, F. M., Morgan, C. A., & Niro, P. (2005). Severe decrements in cognition function and mood induced by sleep loss, heat, dehydration, and undernutrition during simulated combat. Biological Psychiatry, 57(4), 422–429.

    Article  PubMed  Google Scholar 

  • Lindseth, P. D., Lindseth, G. N., Petros, T. V., Jensen, W. C., & Caspers, J. (2013). Effects of hydration on cognitive function of pilots. Military Medicine, 178(7), 792–798.

    Article  PubMed  Google Scholar 

  • Liu, K., Sun, G., Li, B., Jiang, Q., Yang, X., Li, M., . . . Liu, Y. (2013). The impact of passive hyperthermia on human attention networks: An fMRI study. Behavioural Brain Research, 243, 220–230.

    Article  PubMed  Google Scholar 

  • Logothetis, N. K. (2008). What we can do and what we cannot do with fMRI. Nature, 453, 869–878.

    Article  PubMed  Google Scholar 

  • Luippold, A. J., Charkoudian, N., Kenefick, R. W., Montain, S. J., Lee, J. K. W., Teo, Y. S., & Cheuvront, S. N. (2018). Update: Efficacy of military fluid intake guidance. Military Medicine, 183(9-10), e338–e342.

  • MacLeod, H., Cooper, S., Bandelow, S., Malcolm, R. A., & Sunderland, C. (2018). Effects of heat stress and dehdyration on cognitive function in elite female field hockey players. BMC Sports Science, Medicine and Rehabilitation, 10, 1–12.

    Article  Google Scholar 

  • Marino, F. E., & King, M. (2010). Limitations of hydration in offsetting the decline in exercise performance in experimental settings: Fact or Fancy? In M. Bishop (Ed.), Chocolate, Fast Foods and Sweeteners: Consumption and Health. Hauppauge, NY: Nova Publishers.

    Google Scholar 

  • Montain, S. J., Latzka, W. A., & Sawka, M. N. (1999). Fluid replacement recommendations for training in hot weather. Military Medicine, 164(7), 502–508.

    Article  PubMed  Google Scholar 

  • Moore, R. D., Romine, M. W., O'connor, P. J., & Tomporowski, P. D. (2012). The influence of exercise-induced fatigue on cognitive function. Journal of Sports Sciences, 30(9), 841–850.

    Article  PubMed  Google Scholar 

  • Murray-Kolb, L., & Beard, J. L. (2007). Iron treatment normalises cognitive function in young women. The American Journal of Clinical Nutrition, 85, 778–787.

    Article  PubMed  Google Scholar 

  • Neave, N., Scholey, A. B., Emmett, J. R., Moss, M., Kennedy, D. O., & Wesnes, K. A. (2001). Water ingestion improves subjective alertness, but has no effect on cognitive performance in dehydrated healthy young volunteers. Appetite, 37(3), 255–256. https://doi.org/10.1006/appe.2001.0429.

    Article  PubMed  Google Scholar 

  • Rehrer, N. J., & Burke, L. M. (1996). Sweat losses during various sports. Australian Journal of Nutrition and Dietetics, 53(Suppl 4), S13–S16.

  • Rogers, P. J., Kainth, A., & Smit, H. J. (2001). A drink of water can improve or impair mental performance depending on small differences in thirst. Appetite, 36, 57–58.

    Article  PubMed  Google Scholar 

  • Saker, P., Farrell, M. J., Adib, F. R. M., Egan, G. F., McKinley, M. J., & Denton, D. A. (2014). Regional brain responses associated with drinking water during thirst and after its satiation. Proceedings of the National Academy of Sciences, 111(14), 5379–5384.

    Article  Google Scholar 

  • Sawka, M. N., Burke, L. M., Eichner, E. R., Maughan, R. J., Montain, S. J., & Stachenfeld, N. S. (2007). American College of Sports Medicine position stand: Exercise and fluid replacement. Medicine and Science in Sports and Exercise, 39(2), 377–390.

    Article  PubMed  Google Scholar 

  • Schmit, C., Hausswirth, C., Le Meur, Y., & Duffield, R. (2017). Cognitive functioning and heat strain: Performance responses and protective strategies. Sports Medicine, 47(7), 1289–1302.

    Article  PubMed  Google Scholar 

  • Schmitt, J. A. J., Benton, D., & Kallus, K. W. (2005). General methodological considerations for the assessment of nutritional influences on human cognitive functions. European Journal of Nutrition, 44(8), 459–464.

    Article  PubMed  Google Scholar 

  • Sharma, V. M., Sridharan, K., Pichan, G., & Panwar, M. R. (1986). Influence of heat-stress induced dehydration on mental functions. Ergonomics, 29(6), 791–799.

    Article  PubMed  Google Scholar 

  • Silverstein, S. M., Berten, S., Olson, P., Paul, R., Williams, L. M., Cooper, N., & Gordon, E. (2007). Development and validation of a world-wide-web-based neurocognitive assessment battery: WebNeuro. Behavior Research Methods, 39(4), 940–949.

    Article  PubMed  Google Scholar 

  • Streitbuerger, D. P., Moller, H. E., Tittgemeyer, M., Hund-Georgiadis, M., Schroeter, M. L., & Mueller, K. (2012). Investigating structural brain changes of dehydration using voxel-based morphometry. PLoS One, 7(8), e44195.

    Article  Google Scholar 

  • Szinnai, G., Schachinger, H., Arnaud, M. J., Linder, L., & Keller, U. (2005). Effect of water deprivation on cognitive-motor performance in healthy men and women. American Journal of Physiology, 289(1), R275–R280.

    PubMed  Google Scholar 

  • The Australian Defence Force. (2012). Defence instructions - physical training. Canberra: ACT.

    Google Scholar 

  • Tomporowski, P. D., Beasman, K., Ganio, M. S., & Cureton, K. (2007). Effects of dehydration and fluid ingestion on cognition. International Journal of Sports Medicine, 28(10), 891.

    Article  PubMed  Google Scholar 

  • Toney, G. M. (2010). Regulation of neuronal cell volume: From activation to inhibition to degeneration. Journal of Physiology, 588(18), 3347–3348.

    Article  PubMed  Google Scholar 

  • van den Heuvel, A. M. J., Harberley, B. J., Hoyle, D. J. R., Taylor, N. A. S., & Croft, R. J. (2017). The independent influences of heat strain and dehydration upon cognition. European Journal of Applied Physiology, 117(5), 1025–1037.

    Article  PubMed  Google Scholar 

  • Watson, P., Whale, A., Mears, S. A., Reyner, L. A., & Maughan, R. J. (2015). Mild hypohydration increases the frequency of driver errors during a prolonged, motonous driving task. Physiology and Behavior, 147, 313–318.

    Article  PubMed  Google Scholar 

  • Williams, L. M., Simms, E., Clark, C. R., Paul, R. H., Rowe, D., & Gordon, E. (2005). The test-retest reliability of a standardized neurocognitive and neurophysiological test battery: "Neuromarker". International Journal of Neuroscience, 115, 1605–1630.

    Article  PubMed  Google Scholar 

  • Wittbrodt, M. T., & Millard-Stafford, M. (2018). Dehydration impairs cognitive performance: A meta-analysis. Medicine and Science in Sports and Exercise, 50(11), 2360–2368.

    Article  PubMed  Google Scholar 

  • Wittbrodt, M. T., Millard-Stafford, M., Sherman, R. A., & Cheatham, C. C. (2015). Fluid replacement attenuates physiological strain resulting from mild hypohydration without impacting cognitive performance. International Journal of Sport Nutrition and Exercise Metabolism, 25(5), 439–447.

    Article  PubMed  Google Scholar 

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Acknowledgements

The authors would like to thank all the participants of the study who volunteered their time freely, independent of any duties associated with the Australian Defence Force.

Funding

Stephen Goodman held an Australian Postgraduate Research Scholarship from Charles Sturt University (Australia), and this research was sponsored by a grant from the Spitfire Association (grant number 0000101840), awarded to Professor Marino as the Memorial Spitfire Fellow 2016. No further funding was provided by agencies in the public, commercial, or not-for-profit sectors.

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  1. School of Exercise Science, Sport and Health, Charles Sturt University, Bathurst, Australia

    Stephen P. J. Goodman, Ashleigh T. Moreland & Frank E. Marino

  2. School of Health and Biomedical Sciences, Royal Melbourne Institute of Technology, Melbourne, Australia

    Ashleigh T. Moreland

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  1. Stephen P. J. Goodman
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Correspondence to Stephen P. J. Goodman.

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Goodman, S.P.J., Moreland, A.T. & Marino, F.E. Maintaining Euhydration Preserves Cognitive Performance, But Is Not Superior to Hypohydration. J Cogn Enhanc 3, 338–348 (2019). https://doi.org/10.1007/s41465-019-00123-w

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