Extreme conditions, like heat and low humidity, increase both fluid and salt needs. There is a variety of electrolyte replacement options in tabs and powders – flavored or unflavored to meet your preference. Mixing instructions should be included on the package. Keep in mind that more isn’t necessarily better, too much water and/or too much salt can both be dangerous. For those who are heavy sweaters, adding ½ teaspoon of salt to a sports drink can help with replacement as well as encouraging you to keep drinking to stay hydrated.
Most people get enough salt in their diet however if your training and training conditions are more intense, additional salt may improve how you feel. Staying adequately hydrated is best done throughout the day to include the pre, during, and post workout phases. Hope this helps