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A “No Sweat” Approach to Optimizing Hydration – Water is a Key Supplement for Everyone!

vital science - muscle and performance - water - hydration

A “No Sweat” Approach to Optimizing Hydration


Dihydrogen Monoxide, H2O, agua… No matter what you call it, water is a key supplement for everyone!

Dwayne N. Jackson, PhD

Water is a life-source for all living organisms—so why are we covering it as a ‘supplement’? Well, simply because athletes need a lot more of it than the average Joe.

In humans, H2O provides a dissolvable medium for transport of nutrients in blood plasma, saliva, and extracellular fluid. It also makes up the liquid in sweat (needed for thermoregulation) and synovial fluid (needed for lubrication of joints).  The typical adult human is made of over 60% water and, because muscle mass contains up to 80% water, athletes should be even more ‘waterlogged’. The average daily water loss in a resting adult is about 2.6 L, add in heat stress and heavy exercise and water loss can climb as high as 10-12 L per day. Based on this, it’s no surprise that most athletes are dehydrated, a condition which can lead to poor athletic performances and/or serious health consequences.





In the quest for leanness, most reach for fat burning supplements as a first line of defense— we suggest you examine your water intake too! Research published in Obesity illustrates that drinking 500 ml of water prior to each meal can boost weight loss when dieting—in 12-weeks, those who drank water before meals lost about 4.5 lbs. (about 50%) more than those who didn’t drink water before meals. The researchers suggested that drinking water prior to meals increased the feeling of fullness and decreased the total calories consumed per meal.




Researchers from Germany have shown that drinking 500 ml of cold water increases metabolic rate by 30% for about 30 minutes, which equates to a total of about 25 calories burned! In males, water-induced themogenesis is accomplished by burning fat, whereas females burn more carbs. Based on this research, you can expect to burn about 200 extra calories per day if you drink 4 L of cold water daily—seems a lot easier than doing more cardio!




Working out while dehydrated can significantly affect workout volume. In a study published in 2010, researchers from Missouri Western State University reported that subjects who had a controlled 3% body mass loss due to sweating (without fluid replacement) performed 15% less reps when weight training to failure. In another earlier study, scientists reported that dehydration (~3% body mass) led to decreases in average and peak power in the upper body (7% and 15% respectively) and lower body (19% and 18% respectively) during anaerobic exercise.




In a study published in the Journal of the International Society of Sports Nutrition, running athletes, who drank only when they felt thirsty, replaced a mere 30% of the water they lost sweating—despite having open access to water throughout their workouts. This is supported by an observational investigation conducted on elite level rugby athletes who were studied during aerobic and resistance training sessions. It was found that 80% of subjects started training in a hypohydrated state and failed to match water consumption with sweat rate. In fact, during resistance training, subjects over hydrated and during aerobic training subjects didn’t drink enough.

Thus, athletes should follow a predetermined regimen of fluid ingestion if they wish to maintain optimal hydration.




This is a current area of scientific debate. According to research, daily water needs for athletes vary based on body mass, exercise intensity, environmental temperature/humidity, and kidney health.


So how can we guarantee optimal hydration status on a day-to-day basis (without access to a laboratory)?


Well, a physician will tell you to try to drink 8 cups (2L) of water daily and let your kidneys do the rest. On the other hand, the biggest guys in the gym will tell you to drink at least twice that. Interestingly, water ingestion is one area where ‘Bro-science’ is closer to the target than what is ‘pushed’ in medicine.

If you work and/or train in a temperature controlled environment— Drink 2L of water per day as a minimum baseline, then add in 500ml prior to each main meal, and (on training days) drink 500ml, 20-30 minutes before training. This approach will bring your daily water consumption to 4L, timed so that you can take advantage of water’s training and dietary benefits.

If you work and/or train in a hot environment, then you will need to increase your water consumption to match sweat rate. You likely wont have a means to measure your sweat rate or specific gravity of your urine— so we recommend keeping an eye on your urine color and smell, if its clear (i.e., watery) and scentless, then you are hydrated.


More isn’t necessarily better!


Of note, over-hydration can lead to deficits in performance comparable to under-hydration. Moreover, consuming too much water in a short period of time can lead to potentially fatal water intoxication, also known as water poisoning or dilutional hyponatremia. The key to avoiding over-hydration is to sip water throughout the day and pay attention to urine color and smell. Do not chug liters of water in a single sitting.



Kraft JA, Green JM, Bishop PA, Richardson MT, Neggers YH, Leeper JD. Impact of dehydration on a full body resistance exercise protocol. Eur J Appl Physiol. 2010 May;109(2):259-67.

Jones LC,Cleary MA, Lopez RM, Zuri RE, Lopez R. Active dehydration impairs upper     and lower body anaerobic muscular power. J Strength Cond Res. 2008 Mar;22(2):455-63.

Maughan RJ, Watson P, Shirreffs SM. Implications of active lifestyles and environmental factors for water needs and consequences of failure to meet those needs. Nutr Rev. 2015 Sep;73 Suppl 2:130-40.

Passe D, Horn M, Stofan J, Horswill C, Murray R. Voluntary dehydration in runners despite favorable conditions for fluid intake. Int J Sport Nutr Exerc Metab. 2007 Jun;17(3):284-95.

Cosgrove SD, Love TD, Brown RC, Baker DF, Howe AS, Black KE. Fluid and electrolyte balance during two different preseason training sessions in elite rugby union players. J Strength Cond Res. 2014 Feb;28(2):520-7.

Garth AK, Burke LM. What do athletes drink during competitive sporting activities? Sports Med. 2013 Jul;43(7):539-64.

Dennis EA, Dengo AL, Comber DL, Flack KD, Savla J, Davy KP, Davy BM. Water consumption increases weight loss during a hypocaloric diet intervention in middle-aged and older adults. Obesity (Silver Spring). 2010 Feb;18(2):300-7

Boschmann M, Steiniger J, Hille U, Tank J, Adams F, Sharma AM, Klaus S, Luft FC, Jordan J. Water-induced thermogenesis. J Clin Endocrinol Metab. 2003 Dec;88(12):6015-9.

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