Physiological regulation during exercise: Scientific solutions for water replenishment, salt metabolism, and prevention of hidden dehydration

Water is the second most essential nutrient for life after oxygen. A normal adult needs 2400-4000 ml of water daily. During exercise, profuse sweating leads to significant water loss. Running for one hour can result in approximately 1-1.5 liters of sweat, which must be replenished appropriately to maintain fluid balance. Insufficient hydration can lead to dehydration.

Mild dehydration is defined as a loss of 2% of body weight. At 4%, symptoms include severe thirst, rapid heart rate, elevated body temperature, decreased blood pressure, and fatigue. Dehydration of 6%–10% can cause nausea, loss of appetite, and muscle cramps. Dehydration not only affects athletic performance but also impairs the body's ability to dissipate heat, potentially leading to heatstroke or shock.

There are specific methods to follow when hydrating during exercise: Drink some lightly salted water if you sweat a lot. Hydrate in small amounts frequently, ideally 150-200 ml at a time, and no more than 1000 ml per hour. Avoid excessive drinking. Drinking too much at once can cause water retention in the gastrointestinal tract and lead to abdominal pain. Large amounts of water entering the bloodstream can also increase the burden on the heart. The ideal water temperature is 8-12 degrees Celsius.

Carbonated drinks are widely recognized as a contributor to obesity due to their high sugar and calorie content. While these beverages may seem thirst-quenching after exercise, the sugary drinks will replenish the calories burned. Excessive consumption can also negatively impact bones and teeth. Even moderate consumption can affect metabolism and accelerate fat accumulation. After exercise, it's best to replenish fluids with cool boiled water or mineral water.

The main component of table salt is sodium chloride. Excessive salt intake leads to sodium retention in the body. Sodium retention is accompanied by water retention, increasing blood volume and consequently raising blood pressure. The effects of excessive salt intake are more pronounced in obese individuals. Reducing salt intake during weight loss not only helps prevent high blood pressure but also reduces water retention, thus aiding in weight reduction.

Excessive salt intake can worsen diabetes and cause stomach problems. How to reduce salt intake? Consciously correct the bad habit of overly salty food and adding excessive amounts of soy sauce. Adults generally need to consume 3 grams of salt daily. For those accustomed to overly salty foods, add a little vinegar during cooking to enhance the flavor. Reduce the intake of pickles and preserved foods.

Fresh salads are delicious, but it's easy to consume too much dressing. Adding two tablespoons of Thousand Island dressing and one tablespoon of peanut powder is almost equivalent to eating two small bowls of rice. Those trying to lose weight with fresh salads should avoid adding too much dressing. It's recommended to dilute the dressing with low-fat yogurt or vegetable puree.

When using salad dressing, "dipping" is the ideal method. Also, avoid chopping vegetables too finely to prevent them from absorbing too much dressing. Chewing slowly and thoroughly helps with digestion, aiding in the production of saliva and gastric juices. Once food enters the body, blood sugar levels rise, triggering a signal in the brain's appetite center to stop eating.

Eating too quickly means we've already overeaten before the signals for digestion even appear. It's best to eat until you're about 80% full. As the saying goes, "A bowl of soup before a meal is better than any medicine." Drinking a small amount of soup before a meal can moisturize the stomach and intestines and promote digestion. However, the amount should be controlled; too much will dilute digestive juices. Nutritionists recommend drinking a small bowl of soup or fruit juice first, followed by vegetables, and then meat, eggs, etc.

This order of eating allows for the efficient use of nutrients while reducing the burden on the gastrointestinal tract. Eating is a vital physiological activity for maintaining life, but overeating inevitably leads to fat accumulation. It is important to cultivate good eating habits that ensure a normal supply of various nutrients without creating excess energy.