Salt and Hydration
In the practice of hot yoga as well (as any type of intense exercise or activity in a hot environment), the loss of fluid combined with salts through sweat behooves the practitioner to pay close attention to hydration. I cannot overemphasize the significance of hydration on a daily basis for the practice of hot yoga.
Hydration is a balance of sufficient fluid and electrolytes to support the circulatory and nervous systems. By the time thirst kicks in, we’re actually significantly dehydrated. We might often go about our lives slightly dehydrated, which may not be so noticeable in daily activities, but a 1% loss of fluid is estimated to affect physical and mental performance by about 10%! Doing hot yoga increases the demand on the body so, coupled with loss of fluids through the sweat, the effect of even minor dehydration is magnified enormously. This results in a very tangible effect on performance, with dizziness, nausea, cramping and even loss of mental focus.
It’s important to stay hydrated throughout the day; it’s difficult to “catch up” in the yoga room. In fact, drinking too much water in class can make you feel water-logged: a full stomach can cause nausea and discomfort in and of itself, especially with the compressions and stretches to the abdominal area during class. Most people could use approximately two litres of water just for daily maintenance with regular activities. Add the profuse perspiration that happens during intense exercise and activity in the heat, and another one to two litres should be consumed, for a total average of three to four litres – depending on your size and general physiology. This should be spread out throughout the day, so carry your water bottle with you. And remember: drinking other liquids counts toward hydration, but caffeinated beverages don’t count fully (as they promote diuresis and some fluid loss) and sugary drinks are sub-optimal and many are loaded with preservatives and additives.
Also remember: salts and minerals are lost in sweat and need to be replaced as well, or the body can’t retain the fluids consumed. The term electrolyte refers to these salts and minerals once they’re dissolved. Sodium, potassium, chloride, magnesium and calcium are essential to replace. Besides helping with proper regulation of body fluids, they assist in nerve conduction, muscular contraction and energy production. They are critical in functions such as cell membrane permeability, adrenal function, digestion, and metabolism.
Eating fruits and vegetables, along with some added salts, often sufficiently replaces most daily electrolyte needs. However, engaging in extreme physical activity like hot yoga necessitates supplementing your electrolytes diligently. Many sources for electrolyte replacement are available, though the simplest and most accessible is plain good quality unrefined salt. Himalayan rock salt and unprocessed sea salts are examples as they contain trace minerals. Refined table salt is often composed primarily of sodium chloride (97%), with a small amount (3%) composed of additives such as iodine and others, primarily for moisture-wicking and anti-caking properties (for easy pouring) such as silicon dioxide, calcium silicate, aluminum silicate, and corn sugar (yes, sugar!).
One of the main concerns for salt intake has been the general recommendation to limit salt for the presumed assumption that this improves circulatory health and is better for the cardiovascular system. Recent research is demonstrating that salt intake and its relation to circulatory health is a J-shaped curve. This means there is an optimal level, with too little and too much detrimental to the cardiovascular system. The original population-wide recommendation to diminish salt intake to less than 1.5 grams of sodium per day was based on short-term research on hypertensive patients. To recommend this to the general population based on research in a select group with an underlying condition may have been premature. Too little sodium in a healthy person can have its own deleterious effects.
More recent studies suggest a moderate sodium intake of 3-5 grams of sodium per day might be more prudent. One-half teaspoon of salt has about 1100 milligrams (1.1 grams) of salt. *
An hour of sweating due to moderate activity in the heat could result in about 0.5 liter of fluid loss along with 1.2-1.5 grams sodium loss, with some variability between individuals. Remember that 1/2 teaspoon of salt contains 1.1 grams, so it would be reasonable to add 1/2 teaspoon to your half-liter water bottle and consume that to replace what you may lose. In my opinion, it’s probably even best to consume this ahead of time to be hydrated in advance. ^
Figuring out what your individual needs are relative to you size, level of intensity applied in a given session and the associated amount of sweat and loss of salts requires a delicate balance. Ultimately, moderation is the key with a critical eye to your own response to your salt consumption.
Written by Roxana Mavai
*Citation: Circulation Research 2015 Mar 13;116(6):1046-57.
^Citation: Journal of Occupational Medical Toxicology 2008; 3: 4.
Published online 2008 Jan 29