Sodium may often be considered unhealthy, especially if you're consuming too much of it in the form of salty foods. But human bodies actually need sodium to function properly. Here's how to understand sodium loss during exercise and how to make sure you're getting enough of it — and not too much.
The amount of sodium you lose during exercise depends on a variety of factors — including genetics, your level of fitness, your diet, the concentration of sodium in your sweat and your environment. On average, you lose about 500 milligrams of sodium per one pound of sweat lost during a workout.
Health Effects of Sodium
Your body requires a certain level of sodium to function properly, particularly to maintain blood pressure, blood volume and muscle use. But you also lose a good deal of sodium as you sweat through an intense workout.
Sodium is often referred to as an unhealthy part of certain foods, but human bodies in fact need a certain amount of sodium in order to survive. According to the American Heart Association, you need a minimum of about 500 milligrams of sodium a day to maintain certain bodily functions, like moving your muscles, transmitting nerve impulses and balancing bodily fluids.
However, it's rare for a person to consume only 500 milligrams of sodium a day. To get a sense of how that fits into the average American diet, note that a single bagel contains nearly 500 milligrams of sodium. The American Heart Association recommends eating no more than 2,300 milligrams of sodium a day, though on average, Americans consume over 3,400 milligrams a day. It's not surprising that the American diet — filled with processed meats, breads and cheeses — is high in sodium.
Consuming such a high level of sodium can have a negative effect on health. Your kidneys work to maintain a level of sodium in your body, but if it builds up in excess, it ends up in your blood, leading to high blood pressure. The American Heart Association also notes that eating too much salt has been linked to stroke, heart problems, kidney disease and headaches, as well as weight gain.
Excess sodium has also been generally linked to having a poor effect on pretty much every organ in the body. A November 2016 study published in the Journal of the American College of Cardiology found that too much salt was detrimental to blood vessels, heart, kidneys and brain.
Sodium Loss During Exercise
So to maintain healthy sodium levels and exercise, you need to sweat once a day, right? It's not so simple. In fact, it takes quite a lot of exercise and sweat for you to lose a good amount of sodium.
When you exercise, you start losing water and electrolytes through your sweat. Sweating is the main channel for sodium loss during exercise. Electrolytes are minerals in your blood, tissues and body fluids that have an electric charge and work to balance your body's water levels, pH level, nutrients and cell waste, according to MedlinePlus.
Along with sodium, calcium, potassium, phosphate and magnesium are all electrolytes that you get from food and drinks. If you sweat out too much rapidly and don't drink enough water, you may experience dehydration, or the loss of fluids from your body.
It turns out that sodium loss during exercise can be a pretty complicated thing to measure — and researchers have been studying it for a while. It's important to calculate how much an athlete sweats and loses sodium during a period of training because this can help them decide how much they need to replenish in fluids, electrolytes and salt, according to a March 2017 study published in Sports Medicine.
Sodium Loss Factors
On average, you'll lose about 500 milligrams of sodium for every pound of sweat you secrete. But this will vary for each individual, as sweating depends on a number of factors, ranging from your genetics, body weight, diet and heat acclimatization.
The environment and heat play a large role as well. Running for a long distance in the summer heat will make you sweat and lose a lot more sodium than a brisk walk in the winter, requiring you to eat and drink enough sodium and electrolytes afterwards to replenish your body.
If you're an extremely active person, like a professional athlete training for hours in the sun daily, you may lose up to thousands of milligrams of sodium per day, according to Harvard Health Publishing. The daily sodium intake for athletes could be a bit higher than the average person, and would give them more leeway to consumer slightly higher levels of sodium throughout the day.
But if you're simply working out at the gym for about half an hour a day, working a desk job and otherwise living a sedentary life, your sodium loss during exercise may not be enough to warrant a salty diet. Thus, exercise and sweating purely for the assumption that it will clear your body of excess sodium may not always work. Diet is a key factor as well.
In addition to your daily workouts or physical activity outdoors in the heat, you need to tailor your diet to balance out your sodium levels and keep them healthy. Even if you cut out all salt-packed fast food and processed foods, and maintain a balanced diet of vegetables, fruit and fresh meats, you'll likely be consuming more than enough sodium than your body needs.
To eat a low-sodium diet, you'll need to avoid most packaged and processed foods, including cookies, baked goods, deli meats, chips and frozen meals. If it's easier to visualize, your body only requires about one-fourth teaspoon of table salt every day, and that can easily be found naturally in meats, vegetables and dairy, in addition to some salt for seasoning with meals.
Choose low-sodium foods like fresh vegetables, fruit, legumes, nuts, seafood and meats. If you're still worried about your salt intake, remove the salt shaker from your table and instead season your food creatively with olive oil, crushed red pepper, vinegar, garlic, lemon, ginger or spices.
- American Heart Association: "How Much Sodium Should I Eat Per Day?"
- American Heart Association: "Effects of Excess Sodium Infographic"
- Journal of the American College of Cardiology: "Dietary Sodium and Health: More Than Just Blood Pressure"
- MedlinePlus: "Fluid and Electrolyte Balance"
- Sports Medicine: "Sweating Rate and Sweat Sodium Concentration in Athletes: A Review of Methodology and Intra/Interindividual Variability"
- Harvard Health Publishing: "Ask the Doctor: Exercise and Sodium"
- University of California San Francisco: "Guidelines for a Low Sodium Diet"
- USDA FoodData Central: "Bagels, Wheat"