This summer, I've shifted how I run. I've been using run/walk intervals to rebuild endurance in the Texas heat while keeping training consistent and manageable. After an extended inconsistent running schedule, I wasn't heading into the summer with my usual running base, and that changed how I approached my training.
Texas in August is hot, y'all. I don't even say "y'all." I'm originally from Pennsylvania. I just threw it in for effect. Even early in the morning, it can already be in the 80s with humidity that makes everything feel heavier. In past summers, I could head out for two-mile runs in 80 or 90 degree temps at a steady pace or break it up into two shorter efforts with a quick rest in between. My fitness was higher, and the heat felt more tolerable because of it.
This time around, my runs are much slower. On paper, it looks like a step back. In practice, I'm covering twice the distance I used to in the summer. Instead of calling it at two miles in the heat, I'm often going four or more with walk breaks. It's longer time on my feet, I've noticed the benefits, and I’m able to stay consistent despite the heat.
Longer Time at Moderate Intensity Builds Aerobic Fitness
When the overall effort level stays the same, two miles without breaks and two miles with walk breaks differ in how long your body stays engaged. A 17-minute run at a moderate pace is beneficial, but if you cover the same distance in 25 minutes with walk breaks, your heart and lungs are working for longer overall. That extra time under load is what helps build aerobic capacity.
These longer sessions improve endurance, help manage fatigue, and perceived effort. The extra minutes spent moving, even with brief heart rate drops during walk breaks, still add up to meaningful time in an aerobic zone that supports long-term fitness.
Shorter, faster runs are still helpful. They play a role in developing VO2 max, improving speed, and pushing aerobic thresholds. But those sessions ask more of the body and require a stronger base to support them. Right now, I'm focused on rebuilding that base and being consistent through the heat. There will be plenty of time for speed work in the cooler temperatures of fall once I have a stronger base.
How I Use Run/Walk Intervals
There are different ways to structure run/walk intervals, and I've tried a few this summer based on how I'm feeling, the temperature, and what I want out of the run. Some methods are more structured, and others rely more on how I feel.
Timed Intervals
This approach uses a set schedule, like two minutes of running followed by 30 seconds of walking. Some runners prefer this because it removes the guesswork. It's easy to program on a watch, and it helps create a rhythm.
While I've used this format in the past, I don't always love how it forces a walk or run when it might not feel necessary. Sometimes I want to keep going, and other times I'm ready to walk before the timer says to. It can be helpful, but I often lean toward something more flexible. But that’s just my preference. The best choice is the one that works for you.
Intuitive Intervals
This method has no timer. I run until I feel like walking and walk until I’m ready to run again. As fitness improves, the running stretches naturally get longer and the walking shorter, adjusting in real time based on how I feel. It works well for anyone building up to running continuously without walk breaks. I feel obliged to point out that here some runners prefer the run/walk method no matter how advanced they get, and it is a valid and effective way to train.
I've used intuitive intervals the most over the years. It allows me to be more aware of how my body is responding, and it helps me avoid pushing when I'm not recovered or overheating.
Heart Rate-Based Intervals
Recently, I've been experimenting with heart rate to guide my run/walk decisions. When the heat is high, I set a heart rate alert to notify me when I move into zone three. If that happens, I slow down or walk until my heart rate drops below zone two. Then I begin running again and let it rise gradually into Zone two. I literally follow my heart.
It usually has a slower overall pace than my other interval methods, but has been especially helpful in staying consistent on hot days. It helps prevent overheating and reminds me how much more effort it takes to train in the heat. My pace might be slower, but my effort stays where it needs to be to build endurance without draining recovery.
Training Through the Heat Requires a Smarter Approach
Heat and humidity change the equation. Heart rate climbs faster, recovery slows down, and hydration becomes a bigger priority. Forcing fast paces in these conditions doesn’t leave much room for progress.
Walk breaks help manage effort and extend the session without overreaching. I’m able to stay consistent, get more time on my feet, and recover more effectively. That consistency adds up, especially over a long, hot season.
This approach gives me room to adapt. Instead of skipping runs or pushing too hard, I can train through the heat in a way that feels sustainable.
Building Toward Long-Term Gains
These runs may be slower, but they’re steady and productive. Spending more time at a manageable effort supports aerobic development and helps rebuild my base.
I’m not rushing the process. As fitness builds and the weather cools, the pace will naturally improve and walk breaks will shrink. For now, I’m focused on staying out there longer, finishing strong, and setting up a solid foundation for what comes next.
There's value in all types of training. Fast runs have a purpose. So do slower, longer ones. Right now, I'm focusing on what makes sense in this season. Run/walk intervals are helping me stay consistent, build fitness, and keep running something I want to do, not something I dread.
Training doesn't have to look the same every season to be effective. It has to make sense for the conditions, the goals, and the person doing the work. That's where the real progress happens.
Questions? I’d love to help.
Lea
Lea Genders is a board-certified health coach, personal trainer, and workplace wellness consultant based in Fort Worth, TX. She offers corporate wellness programs for employee health and productivity, as well as in-person and virtual training / coaching for individuals worldwide. Her blog shares expert guidance on strength training, running, and sustainable nutrition @fortworth_trainer
Run/walk intervals have been my go-to this summer for staying consistent in the Texas heat. They let me keep my heart rate in check, extend my time on my feet, and build endurance without overreaching. Whether I’m using timed segments, going by feel, or following my heart rate, the flexibility helps me adapt to the conditions and train in a way that’s sustainable. This approach works for anyone navigating challenging weather, rebuilding fitness, or simply wanting running to feel good!