Training in the Heat: Stay Safe and Perform Better

A Sports Nutritionist’s Guide to Summer Training

By Barbara Lewin, RDN, LDN
Sports Nutritionist and Functional Dietitian

Summer is a great time to train, but exercising in hot and humid weather can quickly turn a good workout into a difficult one. Fatigue, dehydration, muscle cramps, headaches, and poor performance are common when athletes don’t adjust their nutrition and hydration for the heat.

The good news is that your body can adapt. With the right fueling and hydration plan, you can train safely while continuing to improve your performance.

Give Your Body Time to Adjust

Your body needs time to adapt to exercising in the heat. This process, called heat acclimatization, usually takes 7 to 14 days.

As your body adapts, you’ll sweat more efficiently, regulate your body temperature better, and your heart won’t have to work as hard during exercise.

Don’t expect your first few workouts in the heat to feel easy. Start gradually and let your body adjust.

Hydrate Before You Feel Thirsty

If you’re thirsty, you’re already starting to become dehydrated.

Even a small loss of body water can reduce endurance, increase your heart rate, and make workouts feel much harder than they should.

Begin each workout well hydrated and continue drinking fluids throughout your training session. Weighing yourself before and after exercise can help estimate your sweat losses and determine how much fluid you need to replace.

Don’t Forget Your Electrolytes

Water is only part of the equation.

When you sweat, you lose important electrolytes, especially sodium. Replacing water without enough sodium may leave you feeling tired, crampy, or unable to recover well.

If you’re unsure which sports drink or electrolyte product is best for your training, be sure to read my article, “The Best Electrolytes for Athletes: Improve Hydration, Recovery, and Performance.” It explains how electrolytes support hydration, endurance, recovery, and athletic performance.

Eat Enough Carbohydrates

One of the biggest mistakes I see athletes make during the summer is under-fueling.

Training in the heat increases your body’s demand for carbohydrates. Without enough fuel, your muscles run low on glycogen, causing energy levels and performance to drop.

A meal or snack containing carbohydrates before exercise and a combination of carbohydrates and protein after your workout will help support both performance and recovery.

Slow Down When Necessary

Hot weather isn’t the time to chase personal records every day.

Listen to your body and adjust your pace when temperatures or humidity rise. Training by effort instead of pace can help you stay safe while continuing to build fitness.

Know the Warning Signs

Stop exercising immediately and seek medical attention if you experience symptoms such as dizziness, confusion, nausea, chills, severe headache, or excessive fatigue. These may be signs of heat illness and should never be ignored.

The Bottom Line

Training in the heat doesn’t have to slow you down. With proper hydration, electrolytes, smart fueling, and gradual heat acclimatization, you can continue to train safely and perform your best all summer long.

Ready to train smarter this summer? During my Special Introductory Session, we’ll develop a personalized hydration, fueling, and recovery plan based on your sport, sweat rate, training schedule, and performance goals. Together, we’ll take the guesswork out of sports nutrition so you can stay healthy, recover faster, and perform at your highest level, even in the heat.