AI Running Coach - Personalized Training Plans by GPT-4o

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We sweat a lot when we run. Sweating not only leads to dehydration but also causes the loss of electrolytes, namely salts. Therefore, when running, we need to replenish both water and salt. Nowadays, various sports drinks and salt tablets are popular, and it seems that we should drink sports drinks during and after running.Is this really the case?

1

First, how do you determine if you need to hydrate?

Feeling thirsty means your body is starting to dehydrate, but thirst cannot be used as an indicator of whether the body is dehydrated. One way to check the body's water balance is to weigh yourself before and after exercise. It's best to weigh yourself in the morning after a bowel movement. Comparing your weight before and after exercise can estimate the loss of water in the body during exercise. Only by replenishing the lost water in time can you maintain stable body functions.

Another way to check the body's water balance is through a urine color test. Light-colored urine indicates normal hydration levels. The darker the urine, the lower the body's water content.

2

Next, how do you scientifically and systematically replenish water and salt?

Hydration before exercise

Check your hydration status before exercise, as the body's fluid needs vary from person to person.

Drink 450-600 ml of water or sports drink at least 4 hours before exercise.
Drink 200-350 ml of water 10-15 minutes before exercise. Consuming an appropriate amount of drinks, sodium (salt), or snacks helps stimulate the body's need for water and keeps the body hydrated.

Hydration during exercise

For exercise lasting less than 1 hour, drink 100-200 ml of water every 15-20 minutes.
For exercise lasting more than 1 hour, drink 100-200 ml of sports drink (containing 5%-8% carbohydrates and electrolytes) every 15-20 minutes. At the same time, the intake should not exceed 1 liter per hour.

Hydration after exercise

Compare your weight before and after exercise and check the color of your urine to estimate fluid loss. Generally, you should replenish fluids within 2 hours after exercise.

For every 500 grams of weight lost, drink 550-700 ml of water or sports drink.

Of course, the above are guidelines from the American College of Sports Medicine on hydration, which may not be very practical, as carrying water while running does not fit most runners' exercise environments. It can actually be understood more simply.

① For exercise lasting less than 1 hour, just hydrate.

If you run for less than an hour every day, just hydrate, i.e., drink plain water. It doesn't matter whether you drink water at intervals during exercise or drink it all at once after running; it depends on personal habits.

② For exercise lasting more than 1 hour, hydrate in the first hour, then replenish some electrolytes.

If you engage in high-intensity training or competition for more than an hour, you will sweat a lot. Although the loss of salt is not as much as the loss of water, some salt loss does occur. To maintain electrolyte balance, it is necessary to replenish electrolytes. Sports drinks are the first choice, and only marathon races require salt tablets, but they are not a must.

三

Hydration should be moderate.

Excessive hydration can cause "water intoxication." Water intoxication occurs when the body takes in too much water, leading to fatigue, dizziness, drowsiness, nausea, vomiting, weight gain, muscle cramps, weakness, paralysis, and even death. Therefore, it is recommended not to consume more than 1 liter of fluid per hour. However, the probability of this happening is low, so there is no need to worry too much. Most runners only have insufficient water intake rather than excessive intake.

Generally speaking, water intoxication can be avoided by limiting fluid intake and increasing salt (sodium) intake. If water intoxication symptoms are suspected, it is recommended to go to the hospital for timely treatment.

Finally, although sweat is salty, it does not mean that salt loss is as severe as water loss. In fact, dehydration is more severe when sweating. Therefore, for most running enthusiasts, it is important to develop the habit of hydrating during daily exercise.

As for salt replenishment, it is only necessary for exercise lasting more than 1 hour.
Sports drinks are not essential during exercise. For those looking to lose weight, be cautious with sports drinks as they contain sugar.