How to Run and Train Safely in High Heat

Written on 08/14/2026

High temperatures are unavoidable during Texas summers, but they do not have to stop your training. With a few smart adjustments, you can protect your heart and body while continuing to build toward your goals.

When temperatures and humidity rise, your body works harder to cool itself. This can increase cardiovascular strain and the risk of dehydration, heat exhaustion and exertional heat illness.

We spoke with Ryan Quinn, MD, a board-certified sports cardiologist at Ascension Texas Cardiovascular in Austin. Dr. Quinn specializes in preventive cardiology and works with active people and athletes to address their unique cardiovascular needs.

Here is how to stay safe, train smart and keep getting in your miles during the Texas heat.

A hand holding a triangular warning sign with a red border and a black exclamation mark in the center, reminding everyone to train safely and prioritize running safety. Austin Marathon Half Marathon & 5KKnow the Warning Signs

Stop running, move to a cool place, and let someone know if you experience:

  • Dizziness or lightheadedness
  • Headache or nausea
  • Unusual weakness or fatigue
  • Muscle cramps
  • An unsteady walk
  • A weak or rapid pulse
  • A sudden decline in coordination or performance

These may be warning signs that your body is struggling to manage the heat.

Confusion, disorientation, collapse, seizure, unusual behavior or loss of consciousness may indicate exertional heat stroke. This is a medical emergency. Call 911 and begin rapid cooling with cold compresses, shade and fanning, when available, while emergency help is on the way.

Close-up of a wall clock showing the time as 11:59, with the second hand near the 12. The clock face is white with black numbers, and the image is slightly tilted—serving as a timely reminder about running safety and how important it is to train safely, especially when every minute counts. Austin Marathon Half Marathon & 5KChoose the Right Time to Run

Whenever possible, schedule outdoor workouts for early in the morning or later in the evening. Avoid the middle of the day, when direct sunlight and temperatures are often at their highest.

Before heading out, check the temperature, humidity, heat risk and air quality. Even a familiar route may require a different plan when conditions become more demanding.

Give Your Body Time To Adapt

Heat acclimatization happens gradually. The American College of Sports Medicine recommends allowing approximately one to two weeks of repeated, progressive exposure for most heat-related adaptations to occur.

Begin with shorter, easier workouts. Gradually increase your duration and intensity as your body becomes more comfortable in the conditions.

A person wearing a cap and sunglasses drinks water from a plastic bottle outdoors, with sunlight shining brightly in the background—demonstrating important running safety tips to train safely in heat. Austin Marathon Half Marathon & 5KStart Hydrated and Keep Drinking

Do not wait until the middle of your run to think about hydration. Drink fluids throughout the day and begin your workout well hydrated. Pre-hydration with or without electrolytes can go a long way.

Carry water, plan a route with water access or create shorter loops near your home or vehicle. Longer or more demanding sessions may also require electrolytes, particularly for runners who sweat heavily. If you are one of those people, drinking 16-32oz of water mixed with electrolytes prior to a run is very helpful.

Hydration supports circulation and sweating, which are both important for regulating body temperature.

A woman in athletic wear jogs outdoors under a clear blue sky, wearing wireless earbuds and a smartwatch, with her hair in a ponytail—demonstrating how to run in high heat while staying mindful of running safety tips. Austin Marathon Half Marathon & 5KDress for the Conditions

Wear loose, lightweight and breathable clothing. Lighter colors can help reduce heat absorption, while a hat or visor may provide additional sun protection.

Apply sunscreen before heading outside and reapply it according to the product instructions. Choose shaded routes when possible and avoid exposed pavement during the hottest parts of the day.

A person uses a stylus to check off items on a digital checklist labeled “PLAN” displayed on a tablet screen, making sure to include running safety tips and reminders to train safely in heat. Austin Marathon Half Marathon & 5KPlan Before You Head Out

Heat can make a small problem more serious, so avoid putting yourself in a situation where you are far from help.

Tell someone where you are going, run with a friend or choose a route that keeps you close to water, shade and transportation. Bring your phone and identification, especially during longer workouts.

Check in with your training partners and ask them to do the same for you.

A man in a white shirt is holding a tissue to his nose and appears to be sneezing or blowing his nose, highlighting the importance of running safety tips—especially when you train safely in heat, as allergies and heat can both impact your performance. Austin Marathon Half Marathon & 5KTake Extra Care When You Are Sick

Do not try to push through a hard workout when you have a fever, recent illness, reduced oral intake, or vomiting or diarrhea. These conditions can increase your risk of heat-related illness.

Certain medications (particularly diuretics, ACE inhibitors, and ARBs) and cardiovascular or chronic health conditions may also affect how your body responds to heat. Talk with your doctor before making major changes to your training, hydration or medication routine.