• The foundation of preventing dehydration and heatstroke is "water + electrolytes (such as sodium)."
  • While commercial sports drinks are convenient, be mindful that they often contain many additives like sugar, artificial sweeteners, and flavorings.
  • For short or light exercise, water is sufficient. Electrolyte replenishment is effective during intense exercise lasting over an hour or when sweating heavily.
  • Salt tablets can be useful depending on the situation. Those on a ketogenic diet, who are prone to electrolyte deficiency, should consider them carefully.
  • You can also substitute with a simple homemade oral rehydration solution or "diluted sports drink + a pinch of salt."

Are Sports Drinks Really Necessary in the Hot Summer? Let's Start with the Basics

During the hot and humid Japanese summer, we often find ourselves wanting to gulp down drinks. Dehydration and heatstroke cause not only dizziness, headaches, and nausea, but can also be frightening conditions that affect the brain, heart, and kidneys if they become severe. The Mayo Clinic also warns about the risks of severe heatstroke, and deaths during the summer are reported every year in Japan. So, are "sports drinks" and "salt tablets" really necessary, and what criteria should we use to choose them? Let's break it down simply.

Dehydration and Electrolytes: Why Sodium is Important

We Lose More Than Just Water When We Sweat

Sweat contains not only water but also electrolytes like sodium (salt), potassium, and magnesium. For short, light exercise, water alone is enough to replenish what is lost, but for prolonged exercise, working in hot and humid conditions, or situations with heavy sweating, electrolyte replenishment becomes necessary.

Who Should Be Especially Careful?

Older adults are less likely to notice thirst and can easily suffer from heatstroke even indoors. People who play sports for long periods, work under the blazing sun, or have diarrhea or vomiting need to be careful. Furthermore, those on a ketogenic diet are prone to dehydration and low sodium due to increased excretion of water and sodium caused by glycogen depletion. When our team actually tried it, we found that consciously increasing our salt intake during keto helped stabilize our physical condition.

Pros and Cons of Commercial Sports Drinks and Salt Tablets

Pros

- They are ready to drink and can quickly replenish electrolytes and carbohydrates, making them convenient for intense exercise lasting over an hour or in situations with a risk of hypoglycemia. - Being easily available at vending machines and convenience stores is also a major advantage.

Cons and Precautions

- Many products contain a lot of carbohydrates (sugar and high-fructose corn syrup), and studies have pointed out that consuming them in large amounts daily is associated with an increased risk of obesity, insulin resistance, and fatty liver (Tappy et al., 2010; Stanhope et al., 2013). - Drinks like Aquarius may contain artificial sweeteners such as sucralose, which raises concerns since their long-term effects are not fully understood. - They are not suitable for people who are concerned about additives like flavorings and antioxidants. - Salt tablets provide immediate sodium replenishment, but consuming too much salt raises concerns about high blood pressure. People with underlying medical conditions should consult a doctor.

What Should We Drink Instead of Sports Drinks? Practical Alternatives

Everyday Hydration (Short-term Activities)

For daily commuting, light housework, or shopping, water or barley tea is sufficient. Make it a habit to drink small amounts frequently, and if your urine is a pale yellow color, you are generally in good shape.

Simple Recipe for Prolonged Activity and Heavy Sweating

If you want to avoid commercial products, you can substitute them with a simple drink you can make at home. As a guideline, add 1/4 to 1/2 teaspoon of salt (about 0.5 to 1g) to 1 liter of water, and flavor it with 1 to 2 teaspoons of fruit juice or sugar to make it easier to drink. While the WHO's oral rehydration solution has standards for medical use, a diluted homemade drink is effective enough for light sports purposes. We found that adding a little lemon juice made it easier to drink and keep up with.

How to Read Labels and Choose

When purchasing, be sure to check the ingredient list. The key points are sugar (g/100ml), sodium (mg/100ml) or salt equivalent, and the presence of artificial sweeteners. For prolonged exercise, products with a certain amount of sodium and a moderate amount of carbohydrates are suitable, but for everyday use, we recommend low-sugar options or diluting them before drinking.

How Should We Use Salt Tablets?

Salt tablets are convenient for immediate sodium replenishment, but they are not necessary for everyone. They are effective for people who sweat heavily during endurance sports and experience muscle cramps or dizziness due to a lack of salt. On the other hand, people with high blood pressure or decreased kidney function should avoid excessive intake and consult a doctor.

Conclusion

Sports drinks and salt tablets are tools that are "useful depending on the situation." For short, light exercise, water is sufficient. Consider electrolyte replenishment for intense exercise lasting over an hour, heavy sweating, vomiting/diarrhea, or when electrolytes are easily lost, such as on a ketogenic diet. Commercial sports drinks are convenient, but they often contain carbohydrates and artificial sweeteners, so we do not recommend drinking them in large amounts daily. Making a simple homemade drink or checking labels to choose ingredients are also practical measures. We have tried a few options ourselves and found that regularly using a "diluted homemade drink + a pinch of salt" tailored to the purpose helped stabilize our physical condition.

Disclaimer: The information in this article is for general informational purposes only and does not constitute medical advice. Please consult a qualified healthcare professional before making any health-related decisions.