Using heart rate as a training tool for running is a common practice among runners of all levels and all distances. Like many aspects of health and fitness, heart rate zones and their application in training will vary between each person. Here we’ll dive into what you need to know about running heart rate.
Factors that influence average heart rate while running
During exercise, the body’s demand for oxygen increases. To meet this demand, heart rate increases to allow for increased circulation of blood around the body. The harder someone works during exercise, like by increasing pace or weight, the higher heart rate will go. 
Much like resting heart rate (RHR), there are a number of factors that can influence average heart rate while running. These include many of the same factors that impact RHR, such as age, physical activity level, hydration status, and sleep. Other factors to consider include the environment, stress levels, and caffeine intake.
Heat and humidity
During hot and humid weather, the heart works hard to help keep the body cooled. This extra load leads to an increase in heart rate earlier into a run than would occur on a cooler day. Hot and humid conditions will increase stress on the cardiovascular system, which manifests as a number of physiological changes, including an increase in heart rate. Proper hydration also impacts heart rate in hot and humid environments—for every 1% in body mass lost through sweat, heart rate can increase by 3 to 5 beats per minute (BPM). 
While it’s known that caffeine can be used for a performance boost, it can also lead to an elevated heart rate, especially when taken in high doses. [3, 4] It's recommended that, if you would like to explore using caffeine as a tool before or during your races, you test out its effects during training, as caffeine tolerance during exercise varies between individuals. Negative effects of caffeine intake before or during exercise can include elevated heart rate, anxiety, gastrointestinal problems, and irritability. 
Stress and stressful events can take a toll on your body—both physically and mentally. Chronic stress (manifested as elevated blood cortisol levels) is linked to a number of negative health outcomes, and acute stress can affect heart health, including heart rate. According to an article published in JAMA, an increase in both emotional and physical stress can lead to a number of physiological changes including an elevated heart rate. 
Step 1 for finding your ideal running heart rate: calculate maximum heart rate
Ideal running heart rate can be calculated in a number of ways. The most accurate ways are by undergoing a VO2max test or by doing a max heart rate (MHR) test. If you’re unsure of what your MHR is, there are a number of formulas that calculate estimated MHR using age-predictive equations. The most common of these include the Gulati formula and Tanaka formula (though the Fox formula is also common).
Here's how to calculate MHR with these formulas in an example 33-year-old athlete:
Tanaka formula: 208 - 0.7 x age
208 - 0.7 x 33= 185 bpm
Gulati formula: 206 - 0.88 x age
206 - 0.88 x 33= 177 bpm
Of note, the Gulati formula should only be used in females as it is intended to address the unique aspects of female physiology.  It has been found that this particular formula can give inaccurate calculations in others. 
Heart rate tracking data measured during max or all-out efforts can also be used to estimate MHR in lieu of an MHR test. Example measurements might be from at the end of a 5 or 10k race and will ideally be taken with a chest heart rate strap for the most accurate reading. [8-10]
Calculating heart rate zones for training and running
An accurately calculated MHR is an important first step to calculating suggested heart rate zones.  Training that is structured to heart rate zones can help runners improve performance and aid in injury prevention by avoiding under- or overexertion. Such a structure also improves recovery between training sessions and helps to prevent overtraining syndrome.
Below are general running heart rate zone guidelines, though some running coaches may use slightly different percentages for their athletes to provide an individualized approach to running heart rate zones. 
Zone 1: 50-60% MHR
Zone 2: 60-70% MHR
Zone 3: 70-80% MHR
Zone 4: 80-90% MHR
Zone 5: 90-95% MHR
Running training plans should include a variety of different types of runs based on these heart rate zones. This includes long runs, tempo runs, and interval runs for speed work. General recommendations suggest that 80% of runs should be at low or easy intensity (zones 1-3) and 20% of runs should be hard or high intensity (zones 4 & 5).  This distribution will vary between runners depending on their fitness level, goals, and phases of the training cycle. Each zone has a different purpose in training—lower zones build aerobic capacity and higher zones target lactate threshold. 
*If you’re new to exercise or have any health concerns that can be affected by an increased heart rate, be sure to consult your healthcare provider to find a safe and effective approach to exercise. Consult with a credentialed running coach if you have questions about your specific heart rate zones or training plan and to determine the safest approach to training for you as a runner.
What happens if you run with a high heart rate?
Frequently running with a high heart rate can lead to negative outcomes including chest pain, arrhythmias (irregular heartbeat), delayed recovery, and overtraining. This often leads to injuries, burnout, or plateaus in performance. It is critical to pick and follow a training plan that is not only targeted to your goals but that is also safe and suits your fitness level.
You can check in on your body's recovery by monitoring your RHR daily—RHR will increase with overtraining and poor recovery.  RHR can also increase as an early sign of illness, due to dehydration, during periods of stress, or as a result of poor sleep.
Can your heart rate be too low when you run?
It is not uncommon for runners to have a lower heart rate than their less active counterparts, and it is normal for RHR to decrease as aerobic endurance increases. Runners and other endurance athletes tend to have an RHR between 40-60bpm but could also be as low as 30bpm. While this is considered normal, if your heart rate is dropping but you do not feel well, it is recommended you consult a healthcare professional.
How to optimize your running heart rate
Attention to heart rate during runs can be a helpful tool to dial in your training. Here are a few ways to optimize your running heart rate:
Slow down or reduce the intensity of your run. If you’re new to running, returning to running after some time off, or training for a longer distance, using a run-walk approach can help to keep your heart rate normalized as the body adapts to the new workload.
Stay hydrated. Dehydration can elevate heart rate by putting additional stress on the heart. Showing up ready to run well-hydrated is key to managing your running heart rate.
Be consistent. Regular aerobic exercise like running, walking, and swimming will reduce heart rate over time as the heart becomes stronger and more efficient.
- Running and resting heart rate are useful tools for runners
- Using heart rate training can be beneficial for improving performance and recovery while preventing injury and burnout
- Estimated maximum heart rate calculations using predictive formulas can be a useful tool if you’re just getting started, but actual maximum heart rate may vary
- If you have been tracking heart rate during your runs, using measurements from your max efforts (i.e. the end of a 5k race) can be helpful in targeting your actual maximum heart rate
- Heart rate training zones will vary between each person and throughout training cycles
InsideTracker syncs with wearable fitness trackers like Garmin smartwatches, FitBits, and soon Apple Health and is able to automatically pull heart rate and activity data like runs. From this data, InsideTracker populates ProTips—nuggets of laser-focused recommendations developed by scientists and registered dietitians—to provide real-time feedback.
You can sync your wearable to InsideTracker’s mobile app, no matter which plan you purchase. The Ultimate plan and the Shalane Flanagan Panel both measure the relevant biomarkers for the InsideTracker Endurance goal to guide your Action Plan—a personalized checklist that prioritizes recommendations based on your blood, fitness tracking, and DNA data to guide you toward your goal. Selecting the endurance goal will prioritize recommendations that will help you sustain cardiovascular and muscular performance over longer periods of time, including resting heart rate.
Stevie Lyn Smith, MS, RDN, CSSD, CDNStevie Lyn is a Content Strategist and Team Nutritionist at InsideTracker. As a Registered Dietitian and Ironman triathlete, she enjoys combining her passions to help educate others on how to fuel for overall health and performance. When she’s not swimming, biking, or running with her dog, you’ll find her in the kitchen working on a new recipe to improve her biomarkers.