a small detail can make or break your summer run

Even now, I still feel a lingering fear. In my running career, I never knew danger could be so close. I want to share this nightmare experience with everyone and hope that fellow runners can be more vigilant.

Not long ago, given my good running and training condition, I decided to once again aim for a sub-3:50 marathon (my previous best net time was 3:49).

 

At around 30 kilometers, sweat was pouring down my face like rain, and my quick-dry T-shirt was completely soaked. My steps were unsteady, I felt dizzy, my heart was racing, and I felt like vomiting.

Although I had never experienced this before, my experience told me that these were signs of dehydration and mild heatstroke. So, I immediately stopped running, found a shady spot, and slowly squatted down against a tree trunk. Even after stopping, I continued to sweat profusely, my eyes couldn't focus, my mind was foggy, and I had difficulty breathing. It took 10 minutes for me to slightly recover.

 

After this incident, I specifically studied a lot about dehydration during summer running. I want to share this knowledge with fellow runners. While it may not be the ultimate hydration guide for summer running, I hope this guide can help runners train safely.

 

1. Don't wait until you're thirsty to drink water.

 

This was the most serious mistake I made during this run. At 25 kilometers, I felt fine and didn't hydrate, leading to complete dehydration at 35 kilometers.

 

 

In the summer, the hot weather causes the body to naturally evaporate a lot of sweat. Combined with the large amount of water and salt consumed during running, if you wait until you're thirsty to hydrate, your body is already in a state of mild dehydration.

 

At this point, even if you drink water, you can't replenish the lost fluids, and the more you drink, the thirstier you get. The energy consumption can't be met, and dehydration will become more severe in the latter part of the run, potentially leading to life-threatening situations.

 

2. Hydration isn't just about drinking water.

 

During summer exercise, simply drinking water can't replenish the body's lost fluids and can actually make the situation worse.

 

During exercise, the electrolytes lost through sweat can't be replenished by mineral water. Drinking mineral water not only fails to replenish electrolytes but also increases sweating, leading to further dehydration, accelerated fatigue, and heatstroke. So, what we need is rehydration!

 

Preparing light salt water or specialized isotonic sports drinks during exercise is essential for long-distance running in the summer. I'll share more about how to choose sports drinks later.

 

3. Scientifically calculate how much to hydrate.

 

How much rehydration is appropriate? How should different people hydrate? When exactly should you hydrate?

 

 

 

There isn't an exact blueprint for these questions, but we can still roughly calculate based on our own situation. According to the theory of Masayoshi Sanbonmatsu:

 

Dehydration amount = 10g * body weight (kg) * running duration (hours)

 

Following the principle of replenishing as much as you lose, for example, my body weight is 45kg, and a full marathon takes me 4 hours. This means I need to replenish 1800ml of fluids for a full marathon. If it's summer, I should intake at least 2000ml of fluids.

 

Based on the loss rate of electrolytes and sodium, it's best to prepare at least 500ml of isotonic sports drinks and 1500ml of mineral water.

 

4. When to hydrate during a full marathon.

 

Reasonably distributing hydration time and amount is also an essential quality for a marathon runner. Hydration during running isn't just about hydrating during the run. Instead, it should be reasonably arranged before, during, and after the run.

 

Here is a hydration guide I made after researching. Note that during exercise, you should take small sips to avoid burdening the stomach.

    

5. How to choose sports drinks?

 

To understand how to choose sports drinks, you first need to understand the composition of human sweat.

 

 

From the composition of sweat, it's clear that when the body sweats a lot, replenishing with pure water can't meet the body's needs. You also need to replenish the lost sodium, potassium, calcium, and other trace elements, collectively known as electrolytes.

 

In long-distance running, isotonic sports drinks are the fastest way to replenish electrolytes. This is why marathon aid stations provide not only mineral water but also sports drinks.

 

 

There are many brands of sports drinks on the market, but most don't strictly meet national standards. The only one I use and have always used is Gatorade.

 

 

When choosing a sports drink, first determine what you need to replenish. Then, make sure to understand the ingredients of the drink, and finally compare prices and flavors.

Let me use Gatorade's ingredient composition as an example to show you how to choose sports drinks.

 

Many people who know that you need to replenish electrolytes after exercise might wonder why there are no electrolytes listed. Actually, electrolytes aren't a single component. In a normal human body, they exist in the form of sodium and potassium ions. The relative balance of sodium and potassium ions maintains the function and structural integrity of cells.

In addition, Gatorade contains 6% carbohydrates, which is closest to the isotonic ratio of the human body, making it a standard professional sports drink.

 

 

In the classification of sports drinks, hypotonic drinks only replenish water, isotonic drinks replenish both water and electrolytes, and hypertonic drinks replenish sugars.Therefore, for long-distance exercise, the first choice should be isotonic sports drinks (5-6% carbohydrates). This sugar concentration not only provides enough energy for muscles during exercise but also doesn't affect the rate at which liquids empty from the stomach into the small intestine. This means that Gatorade with 6% sugar concentration is absorbed faster than water, juice, or soda.

  

 

If the carbohydrate ratio in a sports drink exceeds 10g/100ml, it will affect blood sugar levels.

 

In summary, the most important thing when choosing a sports drink is to pay attention to the ratio of sodium, potassium, and carbohydrates. Do you understand now?

Finally, based on my personal experience, I want to remind fellow runners once again: during long-distance running in the summer, you must pay attention to proper hydration.There's no need to compete on speed. The road is always there, and the finish line will always be reached. The important thing is to challenge yourself and ensure safety.

 

I hope this sharing is helpful to everyone and that my nightmare experience wasn't in vain.