HYDRATION

Can dramatically during extraneous activity. “HYDRATION” Key for maintaining complete health and achieving ideal workout performance. Avg. Body Mass = 60-70 % water Can dramatically during extraneous activity. ∴ Maintenance of fluid uptake is EXTREMELY IMPORTANT

 WATER ABSORPTION 65% ICF (intracellular fluid) 35% ECF (extracellular fluid) 25% tissue (interstitial) fluid 8% blood plasma & lymph 2% transcellular fluid Ingested water  water absorbed by small intestine  passed through the bloodstream  continually changing between chief fluid compartments

Water transportation through intestinal mucosa- osmosis process: Initiates at digestive tract  through lumen  into the bloodstream. All regions in the intestine absorb water; however uptake differs in each region, depending on solute presence. Jejunum: Active transport of sugars and amino acids cause transport of salt and water  maximum water uptake. Ilium: Active sodium transport is the main cause of water movement. Lumen: Capillary filtration interchanges the water from blood into tissue fluid, where eventually it is absorbed by the ICF compartment.

If tissue fluid osmolality increases, water moves out of cells. Intracellular (inside cells) Extracellular (outside cells) During rest and exercise, water moves freely  through plasma membranes where compartment gradients can easily alter If tissue fluid osmolality increases, water moves out of cells. When fluid osmolality decreases, water moves inside cells. Maintenance of electrolyte osmolality within fluid compartments is dependant on their solute concentration. * A vital pathway for athletes

“Sodium-potassium ATPase-pump” Membranes of most cells contain pumps that aid in: - sodium removal from cells into lateral spaces transfer potassium inside the cells Involves use of energy (ATP), so if energy is not accessible, sodium remains in the cells and builds up. “Sodium-potassium ATPase-pump”

 HOW MUCH FLUID IS ENOUGH? Highly Depends On Genetics, body size, fitness level, environment and intensity of exercise --- (INDIVIDUALISED) Up to 1.5L of water can be lost during every hour of exercise, therefore must be replaced to prevent possible decrease in the athlete’s body temperature or blood volume  ‘Dehydration’

BEFORE: Constant fluid intake leading up to training/competition, ensuring all meals and snacks are accompanied with fluid (200-600ml). DURING: Prepare to drink early in the exercise, & continue with small amounts throughout (200-300ml every 15 minutes) POST: (300-600ml straight after) - Sweat and urinary losses continue for 4-6 hours after, so keep hydrating during these crucial periods. If lost at an rate, certain sodium/potassium requirements are vital in the rehydration process. (sport drinks, oral supplements, and or foods high in salt)

Thus allowing for normal cell and organ function. WATER AVAILABILITY is crucial and also a vital element of plasma--- essential in the maintenance of blood volume (BV). If BV is hindered, function of the circulatory system can be modified, causing a delay in an athlete’s performance. During exercise, the nature and intensity defines the amount and frequency of water movement between fluid partitions. The aim of fluid intake is to replace losses and maintain fluid and electrolyte balance. Thus allowing for normal cell and organ function.

If outputs are not replaced, a negative state of fluid balance can be a fatal consequence…  DEHYDRATION

THE ATHLETE SIMPLY SWEATS TO RID OF THE EXCESS HEAT PRODUCED. During exercise, fluid is lost through the by-product of ENERGY PRODUCTION, where ‘heat’ is shifted from the athlete’s body to the environment --- known as ‘SWEATING’. THE ATHLETE SIMPLY SWEATS TO RID OF THE EXCESS HEAT PRODUCED. DEHYDRATION can come about due to body water loss prior to or during exercise... THROUGH--- Faeces or urine Sweat Exhaled breath

Decreased Blood Volume Decreased Skin Blood Flow Decreased Sweat Rate EFFECTS Decreased Blood Volume Decreased Skin Blood Flow Decreased Sweat Rate Increased Core Temperature Increased Muscle Glycogen Use The amount of sweat loss, determines the volume of fluid transported between intracellular space to the interstitial and plasma regions. Primarily dehydration limits and effects the cardiovascular and thermoregulatory responses, as a consequence of reduction in the skin blood flow and sweat rate, thus leading to a high core temperature.

Performance & training ability becomes diminished and prevention of thermoregulation can arise with any dehydration level… Only a 2% loss of water in our body weight whilst performing exercise in a hot or humid climate CAN result in DEHYDRATION.

 ELECTROLYTES +++ minerals/salts, found in our blood and other fluid compartments. Electrolytes determine our; body water, blood pH & muscle function Through extreme perspiration, electrolytes are lost, thus must be replaced with supplements, e.g. fluids, tablets or powders. Our Bodies use; sodium, potassium, chloride, calcium & magnesium. Why? … to function properly … --- Body cells (nerves, heart, muscle) use them for maintenance across the cell membrane & to transport electrical impulses, (e.g. muscle contractions & nerve impulses).

FLUIDS: ELECTROLYTES & CHO With Ultra-endurance activity, fluids containing electrolytes and CHO can become vital in overall performance and energy output. *** 2-3L/hr. can be lost about 10-14 grams of sodium. Thus… rehydration is the key.

Sodium Potassium vital for growth muscle re-build Essential electrolyte for prevention of muscle weakness Needed during exercise where dehydration causes a drop in blood plasma volume, thus sodium helps increase the blood plasma value An electrolyte added to sports drinks to replace ‘lost salts’ through sweat and to stimulate glucose and water uptake in the small intestine --- ensures optimal maintenance in the ECF. Normal Sodium levels in the blood plasma= 136-145mmol/L Potassium vital for growth muscle re-build nerve impulse transmission aids in heart activity prevent fatigue, cramps & muscle weakness

Together, potassium inside the cell and sodium outside the surrounding cells, help convey communication from the nervous system and ensure muscle contraction regulation. In addition, magnesium is another electrolyte that can aid in post exercise recovery, in particular muscle relaxation, through minimising cramps and twitching.

duration and intensity of exercise CHO main fuel for optimal muscle function. Failing to replenish carbohydrate stores before, during & after exercise, particularly with ultra-endurance activities, the body will shut down. --- Our bodies begin to use extra effort to break down & use other fuel stores, which is not ideal. General Rule: >90 minutes of activity 30-60g carbohydrates/hour Maintain stores & prevent depletion However… dependant on the athletes sweat rates digestive tolerance climate duration and intensity of exercise

Sports drinks, powders & gels are ideal methods of maintaining & re-fuelling an athlete’s - Blood glucose levels - Fluid - Electrolytes - Working muscles IMPORTANT… Certain CHO & electrolyte supplements are required mainly to athletes competing or training in events >1-2 hours UNLESS the intensity is extremely high or the individual feels as though they are running low on fuel & perspiration is shown in large amounts. Important --- fluid supplements should be used appropriately to avoid adverse effects.

‘Conditions, consulting a disturbance in ones water balance’ HYPERNATREMIA = high sodium in blood plasma, relative to water concentration HYPONATREMIA= low sodium in blood plasma, relative to water concentration ‘Conditions, consulting a disturbance in ones water balance’

HYPERNATREMIA Insufficient water in the body with plasma sodium >145mmol/L in the ECF (>155mmol/L is life threatening) Causes- water loss in relation to sodium volume in the body due to; inadequate access to water free water loss (renal or extrarenal) prohibited sense of thirst Kidneys - maintain renal sodium excretion through equalisation of sodium intake and any extrarenal losses. As a result, dehydration follows, as intracellular water is moved into the extracellular area, ensuing cellular reduction. Additionally, prolonged events such as marathons or high hot/humid environments can cause fluid loss through skin via extreme sweating   Symptoms Thirst, dehydration, lethargy, irritability, disorientation, confusion, and weakness Severe Symptoms Tremor, rigidity, seizures, coma, and death Neurological symptoms are linked with rapid changes in the serum sodium. An ‘antidiuretic hormone’ (ADH)/vasopressin is released in response to low BP and low salt in water concentration, to instruct kidneys in conserving water and help stimulate thirst. If compromised, reabsorption of water and sense of thirst is prohibited, causing an imbalance of sodium, thus hypernatremia arises.

HYPONATREMIA (OVER-HYDRATION) How it occurs? Excess fluid and insufficient sodium is not ingested during prolonged exercise, causing the extracellular fluid to become “hypotonic” During sustained exercise, extreme perspiration escalates the athlete’s possibility in sodium deficiency in the blood stream. When athlete replaces losses with plain water, without electrolytes, dilution in the ECF occurs, triggering quick onset of ‘severe hyponatremia’ (Na+, <120meq/l), resulting in development of neurological symptoms, such as brain swelling. Video- watch from 47 seconds…stop at 2 minutes….

Furthermore… OVER-CONSUMPTION OF WATER The body is efficient in maintaining fluid and electrolyte balance. Kidneys--- active at managing unnecessary water inside the body, through urine excretion; however when a person consumes a lot of water in a given time, the kidneys are unable to excrete fast enough or when the body is under physical stress, increased secretion of hormone ‘aldosterone’ (vasopressin) triggers the kidneys to ‘conserve’ water, thus water builds up in the blood--- causing water to move into cells and swell as a way of accommodating. However, this build-up causes the water to enter the brain. Inside the brain is only minimal space with packed cells, & when water enters, there is no room for cells to expand. As a result brain swelling occurs, following seizures, coma and eventually death if the victim is not attended to immediately (>48hrs). --- Prompt administration of hypertonic saline (salt) solution is required and water must be constrained. https://www.youtube.com/watch?v=t1nwSuWr_q8 HOWEVER Only in the twentieth century has the seriousness of over hydration Remember the incident in California where two women competed to see who could drink the most water without urinating and one dies from overhydration and the woman runner who died in the Boston marthon from over hydration! As discussed before: HYPONATREMIA is fatal Basically we have sodium in the extracellular fluid > the extracellular fluid increases due to over hydration >dilution> leading to low sodium in the extracellular fluid > electrolytes are unbalanced>body pushes fluid out of the extracellular fluids>fluid travels into the cells in an attempt to balance the electrolytes> tissues become swollen and puffy>can easily been seen clinically in hands and feet > BUT fluid also travels into the BRAIN cells>causing brain swelling or encephalopathy> which can lead to death

--- A healthy kidney can excrete up to 800-1000ml/hour, so drinking this amount per hour cannot harm. --- Except when our bodies undergo physical stress, such as marathon runners. This stress increases ‘vasopressin’ excretion. Vasopressin --- produced by the hypothalamus into the bloodstream to communicate with kidneys to “preserve water”. ** Thus, the kidney reduces excretion to no >100ml/hour, causing build-up of water in the bloodstream. Higher prevalence in inexperienced individuals competing in high endurance fundraising events, exceeding 4 hours thus have more time to continuously drink & place increase strain on their bodies. Those mainly at risk

High intensity, endurance activities, >3 hours REMEMBER! High intensity, endurance activities, >3 hours Obtaining enough sodium, before, during & post, partnered with high water intake is vital. Particularly during hot/humid climates. However! Don’t forget! Activity <1 hour Fuel your body with plain water, & natural sugar, CHO substitutes like fresh fruit during or after trainings/games. Post trainings, opt for natural sodium in foods like certain veggies and eggs. These options will benefit your body without adding any nasty or additional salts and sugars.

INDIVIDUALISE YOUR OWN WATER AND ELECTROLYTE INTAKE! Additionally, athletes need to be aware of misleading guidelines of “drinking as much as they can”, as it is dependent on the type of athlete, their intensity, duration & present temperature. INDIVIDUALISE YOUR OWN WATER AND ELECTROLYTE INTAKE!

AIMEE CECILY STAY HYDRATED!

REFERENCES Agarwal, M, Agrawal, V, Ghosh, AK, Joshi, S 2008, ‘Hyponatremia and Hypernatremia: Disorders of Water Balance’, Department of Internal Medicine, viewed 5 April 2014, <http://www.japi.org/december_2008/R-1.html> Australian Institute of Sport 2011, Electrolyte replacement supplements: AIS Website Fact Sheet – AIS Sports Supplementation Program, viewed 10 April 2014, <http://www.ausport.gov.au/__data/assets/pdf_file/0011/463538/Electrolyte_replacement_11-_website_fact_sheet.pdf> Australian Institute of Sport 2014, Fluid - Who Needs It, Australian Government: Australian Sports Commission, viewed 10 April 2014, <http://www.ausport.gov.au/ais/nutrition/factsheets/hydration/fluid_-_who_needs_it> Ballantyne, C 2007, ‘Strange but true: drinking too much water can kill’, Scientific American, 21 June, viewed 18 April 2014, <http://www.scientificamerican.com/article/strange-but-true-drinking-too-much-water-can-kill/>

Driskell, J, Wolinsky, I 2008, Sports Nutrition: Energy metabolism & Exercise, Taylor & Francis Group, Boca Raton, FL, viewed 30 March 2014, CRC Press. http://faculty.mu.edu.sa/public/uploads/1348479767.566sports%20nutrition.pdf Dugdale, D 2014, ‘Hyponatremia: Symptoms’, Medline Plus, 26 February, viewed 24 April 2014, <http://www.nlm.nih.gov/medlineplus/ency/article/000394.htm> Ellert, M 1998, Nutrient Absorption: Water, GI 4.2 Study Guide, viewed 28 March 2014, <http://www.siumed.edu/mrc/research/nutrient/gi42sg.html?> Elsevier Health 2012, Hypernatremia: background; description, Clinical Key, viewed 3 April 2014, https://www.clinicalkey.com.au/topics/nephrology/hypernatremia.html Elsevier Health 2012, Hypernatremia: cause and risk factors, Clinical Key, viewed 3 April 2014, <https://www.clinicalkey.com.au/topics/nephrology/hypernatremia.html> Guest, N 2014 Hypernatremia or Over Hydration- whose at risk, SportMed.BC, viewed 5 April 2014, < http://sportmedbc.com/article/hyponatremia-or-overhydration%E2%80%94who-risk>

Helmenstine, A 2014 Can you drink too much water, About Helmenstine, A 2014 Can you drink too much water, About.com Chemistry, viewed 3 April 2014, <http://chemistry.about.com/cs/5/f/blwaterintox.htm> Holmes, N 2005, Fluid Requirements of Endurance Athletes, PointHealth, viewed 5 April 2014, <http://pointhealth.com.au/pdf/FLUID%20REQUIREMENTS%20OF%20ENDURANCE%20ATHLETES.pdf> Kravitz, L 2007, ‘Water: The Science of Nature's Most Important Nutrient’, The University of New Mexico, viewed 28 March 2014, http://www.unm.edu/~lkravitz/Article%20folder/WaterUNM.html Kirven, J, Rosner, M 2014, ‘Exercise-Associated Hyponatremia’, Clinical Journal of the American Society of Nephrology, vol. 2, no. 1, pp. 151-161. Mann, J, Truswell, A 2012, ‘Water, electrolytes and acid-base balance’, in 3 (ed.), Essentials of Human Nutrition, Oxford University Press, New York, pp. 125-133. Saladin, K 2010, ‘Water, electrolytes and acid-base balance’, in 5 (ed.), Anatomy and Physiology: The Unity of Form and Function, Mcgraw-Hill Companies, New York, pp. 943-951.