Hydration System
Hydration is a process of providing adequate fluids to bodily tissues, which is very individualized because we all sweat differently. When we exercise, our body temperature rises. Sweating is part of the autonomic nervous system that helps to cool us down. How much you sweat depends on the intensity and duration of the exercise, the environment (weather), acclimation to the weather and clothing. Maintaining adequate hydration levels, which requires a balance of fluid and electrolytes, is essential for supporting your active lifestyle, health and wellbeing.
Dehydration can occur in active people when exercising in hot conditions and not managing hydration properly. In addition to water, sweat contains electrolytes, particularly sodium, with lesser amounts of potassium, calcium, and magnesium. Replacing electrolytes, especially sodium, maybe necessary for active people and athletes participating in strenuous exercising longer than 90 minutes in hot environments. Losing 2% of body weight through sweat significantly impairs exercise performance. Losing 4% or more increase the risk of developing severe heat-related illnesses.
Possible signs of dehydration include fatigue, dizziness, headache, difficulty concentrating, irritability, loss of appetite, nausea, high heart rate, cramps, dark urine, constipation. Symptoms can last well after exercise is completed.
Currently there is no optimal hydration protocols from experts in the field because there are individual sweat rates, sodium concentration in sweat, and environment that vary significantly. Athletes can take the recommendation as a starting point and adjust as needed.
A general hydration guideline for active people participating in sports:
1) Electrolyte drinks: contain mainly sodium with some flavoring, low in sugar, sold in packets or tablets that can be added to water. Electrolyte drinks may be useful before exercising in hot environments, when you are a “salty sweater”, you are in a calorie deficit and controlling your salt intake.
The research is mixed on the amount of sodium replacement, however general guidelines suggest 400-600mg sodium per liter of fluid. You may need more if you’re losing more than 2% of body weight, and if you’re big and tall.
2) Sports drinks: contain sodium and sugar in varying amounts. Sports drinks are useful during exercise more than 2 hours and for replenishing glycogen store after endurance sports.
3) Water: is obviously important during and outside of training. Drinking only water is enough when exercising 1 hour or less. And should be used alongside electrolyte and sports drinks when there’s more than 2% weight loss.
However, drinking only water when you’re participating in endurance events longer than 2 hours can lead to a condition called hyponatremia, or low blood sodium which can be fatal if left untreated.
An easy way to assess hydration status is looking at the color of urine. When you’re properly hydrated the color is pale yellow. Darker colors signify dehydration and you should drink more water.
For athletes of any skill level, adequate hydration is imperative for optimal health and exercise performance. It can be challenging for athletes to navigate their electrolyte replacement needs. Individualized hydration strategy will take into considerations of pre-exercise hydration status, and fluids and electrolyte needs before, during and after exercise.
PMID: 35392595
PMID: 23121349
PMID: 26891166
Krisadee Bodhidatta