Why is HYDRATION so ImpoRTant?

There is often extra stress placed on our body’s hydration status when changing environmental conditions and while performing physical exercise. Thermoregulation is the maintenance of our core body temperature by balancing heat generation and loss. There is a critical way in which hydration status helps regulate our body’s temperature related to our distribution of heat and cooling via perspiration. Big changes in blood volume, which come as our body adjusts to temperature changes, alter the electrolyte balance and directly affect regulation of body temperature. For me personally, this has been a huge game changer when understanding my performance in longer endurance events. For example, I am a very salty sweater and when my body is sweating a lot, I need to intake extra sodium. Further, as my body fatigues and has a harder time to consume fluids, I often have a hard time staying warm and am largely challenged with my clothing choices and proper function of hydration and digestion systems. To me this is fascinating, but it is so individual based on our hydration status, energy expenditure due to exercise intensity, environmental conditions, fatigue state, body temperature, blood pressure, stress response, etc. 

A little more in this area of ‘too much information’, the normal frequency of urination is 6-7 times in 24 hrs; however, a normal range that might be seen is 4-10 as there are many individual variations of this parameter. Take a moment to reflect on your individual rhythms, what is the frequency of how many times a day you go to the bathroom, might you be able to notice any reasons for why the frequency might change? Keep those thoughts in mind as we continue delving into this topic. 

So, what do the kidneys do that is so important? 

The kidneys are responsible for removing waste and extra fluid from our body, they maintain a critical balance of water, salts, minerals (sodium, calcium, phosphorus, potassium…) as discussed above. Importantly, the kidneys release hormones such as aldosterone (from adrenal cortex via angiotensin II) & anti-diuretic hormone (from brain via angiotensin II, which also stimulates thirst) – which cause blood pressure to increase from the retention of sodium and water…this increases blood volume and cardiac output to increase blood pressure. Kidneys also control production of red blood cells, and adjust urine concentration to reflect the body’s needs in regulation of water levels in the body. 

Earlier in this article, we talked about having a healthy balance of fluid in the body, but what if we don’t? If we have an imbalance and are therefore dehydrated, this means that the blood urea nitrogen levels are higher than creatine (by-product of muscle breakdown) levels. This can lead to ‘simple’ symptoms such as headache, thirst, darker urine color, nausea, fatigue. However, dehydration over longer time leads to kidney damage with symptoms such as nausea, vomiting, loss of appetite, fatigue, sleeping problems, urinating more or less than normal, decreased mental sharpness, muscle cramps, swelling in feet and ankles, dry itchy skin, high BP and difficult to control, short of breath, and chest pain. With prolonged dehydration, there can be indications seen in the glomerular filtration rate, i.e., the rate at which blood is filtered each minute from the kidneys; as well as can lead to excretion of sodium in urine (natriuresis). Interestingly, kidney problems can also stem from long-term use of diuretics as they overwork the kidneys and increase sodium retention (also increase blood pressure) …here we are talking about medicines including asprin, naproxen (Aleve), ibuprofen (Advil)…also if excess vitamin A, E, K build-up.

Uh, oh, why might I be dehydrated and what can cause this condition? Dehydration can occur from several reasons in which we lose more fluids than we intake. It might be as simple as not drinking enough, sweating too much (in relation to how much fluid consumed), vomiting/diarrhea, urinating too much, fever, heat illnesses, medicines, etc.

So how do we know our hydration status and what can we do to monitor and/or measure our hydration levels? Some of these you may be familiar with already. In the clinic or with testing of urine and blood samples, we could identify the plasma osmolality, plasma volume, hematocrit concentration, hemoglobin level, urine specific gravity (with refractometer); however, we can have our eyes on simple markers including the color of urine (lighter is hydrated and darker is dehydrated), frequency of urination, changes in body mass before and after exercise sessions, and monitoring sweat rate that indicate hydration status.

How do we change or adjust our hydration status quickly if we observe we are not hydrated? The best and quickest solutions are to consume water, sport drinks, low fat milk, fruit and vegetables, and rehydration supplements. Being aware to consume fluids with electrolytes including essential minerals such as sodium, potassium, magnesium, while understanding that there is also a harmful risk to having too many electrolytes and too much fluid consumption. 

In fact, it is not only to focus on the amount of water/fluid intake a day (general recommendations = women 8 x 200 ml fluid-water/day, men 10 x 200 ml/day), but also to supply your nutrition with B vitamins for maintaining function of our systems. In addition, pay careful attention to the consumption and amounts of caffeination and carbonation, as these are not hydrating (not as hydrating of fluids). 

As we roll into the pre-season, think about this together with your team and support crew and help keep each other regulated. Happy hydrating!