I am an achiever in my nature, and I believe you must apply decent effort in making progress with running. And if you want extraordinary results, the actions should be extra too. For this reason, I challenged myself on each training, increased intensity, and strived for improvement. I often wondered why my heart rate was so high on easy runs, but I continued despite it. No matter how hard I tried, I could no longer jog because of pain and quit until I recovered from my injuries.


The 14 reasons that cause high heart rates on easy runs are the following:

  1. Inaccurate wrist-based optical hr-monitors
  2. Dramatic altitude change
  3. Temperature or humidity shift
  4. Unusual elevation gain
  5. Unsteady ground surface
  6. Physical fatigue
  7. Dehydration
  8. Lack of sleep
  9. Stress and mental health issues
  10. Caffeine consumption
  11. Impact of alcohol or smoking
  12. Recovering from illness and side effects from medications
  13. Pregnancy
  14. Unusual health conditions that a professional physician should explore

The typical runner’s mistake is moving too fast and putting significant effort into each training, resulting in a high heart rate. The coaches and peers warned me about it, but it still didn’t prevent me from making the same mistake several times before figuring out exactly what I was doing wrong.

One thing I understood was persistence in running is good quality but not a silver bullet. A friend of mine likes to say, you can’t give birth to a child sooner if you make love harder. I think this phrase is highly relevant to jogging too. In this article, we’ll go beyond this conventional wisdom and dive deep into the reasons for high heart rate when running and how to lower it.

In this post, we’ll cover the following:

High heart rate while running

The Reason for High Heart Rate During Exercise But Feeling Fine

The most widespread reason for high heart rate (HR) among runners has nothing to do with the athletes but the HR monitors they’ve been using. The wrist-based HR fitness trackers are the most popular and easy-to-use solution, but they can become inaccurate while doing intense sports. You can spot a sudden heart rate increase during exercise, but you’re not out of breath and feel well. Moreover, the faster you move—the higher discrepancy between the displayed and actual pulse will be.

Wrist-based HR monitors from running vendors like Polar and Garmin usually work well on low-intensity training. Still, if you notice a high HR during exercise but feel fine and rested enough before the jogging, chances are your smartwatch or fitness tracker isn’t precise.

A better alternative to a wrist-based pulse sensor is a chest or bicep heart rate monitor belt. They are more precise overall and irreplaceable on high-intense interval training (HIIT). Lastly, check whether your HR tracker is fixed correctly; reboot or reconnect it.

4 External Factors That Cause High Heart Rate While Running

There are several determinants of the running environment that impact your HR. Consider these factors when estimating your target pace and effort before an actual race or training. When traveling to a new country with a different climate, you can experience a high heart rate even on an easy run. Also, when the season changes, for instance, from spring to summer, joggers can experience the exact distance becoming more challenging or their HR increasing. Over time and training, the runner’s body adapts to the new environment and can perform at its best. Four external factors can cause an increase in heart rate: altitude, temperature and humidity, elevation gain, and ground surface.

Running in the mountains

#1 Altitude

The unbreakable rule of nature is the higher you are, the less oxygen is in the air. Our bodies are susceptible to minor changes in the air we breathe, especially under additional loads like sports activities. Lack of oxygen forces us to breathe deep and often. The more often we breathe in and out, the quicker our hearts beat. Consequently, the higher your altitude is, the higher your HR will be at the same distance at the same speed.

Professional runners prepare for crucial races in the mountains. This way, they temporarily put their bodies under additional stress at high altitudes. So, they show better times when returning to more convenient running conditions at lower altitudes.

Running in high temperature and humidity

#2 Temperature and Humidity

A marathon’s ideal temperature and humidity are 60°F/15°C and 40%. If it’s warmer outside or the humidity is higher, our bodies will spend additional energy to cool down or normalize breathing. As a result, the heart will work harder to deliver oxygen to our body parts.

Try morning runs to normalize the heart rate when the weather outside isn’t perfect. Remember to train in weather conditions close to those you’ll have on race day so your body will adapt to the environment, obtain better endurance reserve, and learn how to spend energy more effectively.

Running at high altitude

#3 Elevation Gain

Running uphill requires additional effort and increases the heart rate. Moreover, moving uphill activates the muscles that were previously idle and undertrained. So, the body makes an extra effort to deliver oxygen there. According to scientist and professional runner Renato Canova:

On average, energy consumption increases by 20% when the running surface has an incline of 5°

Schedule a mountain workout to adapt your body to jogging uphill and develop the energy-saving mode. Please note these kinds of runs shouldn’t always be in your training program, but occasionally adding them can substitute your regular fast and intense workouts.

Trail running

#4 Ground Surface

Different ground surfaces could remove or create an additional load, make running easier or more challenging, and impact the heart rate. Ground with shock-absorbing capabilities, like plastic tracks, grass, and dry, stiff trails, makes jogging more effortless and decreases the runner’s HR. Soft and unsteady surfaces like sand, mud and finnenbahn require additional energy for each step and raise the heart rate. The same is relevant for uneven trails—they activate untrained muscles you usually don’t use with your regular runs, and distributing oxygen to them costs additional energy.

To tackle surface challenges and prevent them from increasing your heart rate, wear running shoes appropriate for the surface. There are dedicated sneakers for almost any surface: tar, trail, grass, plastic, and snow. If you can’t address this with special sneakers, consider decreasing your pace so your HR will remain in safe zones.

fitness tracker heart rate fail

9 Internal Factors That Cause High Heart Rate During Exercise

Sometimes I jog the same distance with the same effort in similar weather conditions, but I still wonder why is my heart rate so high when I run. The reason for that could be their internal factors relevant to mental health, habits, or particular lifestyle, like tiredness, dehydration, lack of sleep, stress, caffeine, alcohol, and smoking.

#1 Tiredness

When you are physically exhausted, and your energy level is low, your body will turn to fat reserves and start to burn them to fuel your activity. This internal process is resource-consuming and less efficient. As a result, the runner’s heart has to work quicker not just to distribute the energy but also to fuel its synthesis in the first place.

If you feel tired, rest or maintain a short recovery training instead of an intense workout. They say, a proper recovery run restores muscles and energy stocks quicker.

#2 Dehydration

An inevitable consequence of a well-performed marathon run is dehydration, which is fine when you anticipate it. However, sometimes we might not notice a lack of water in the body or ignore it while performing as usual or with a higher intensity. Jogging while experiencing dehydration could result in headaches, blood pressure increases, running-induced hematuria, dizziness, loss of consciousness, or an unfolding or relapse of chronic heart diseases.

Thus, it is vital to drink enough water and keep your hydration level sufficient, especially under intense physical activities and when it’s hot outside. It might sound weird at first, but it’s very functional and straightforward: in public WCs of some southern countries, the notices help people trigger dehydration according to the color of their urine. Here is one of those labels:

Dehydration chart by the color of the urine

#3 Lack of Sleep

Sleep is the most valuable recovery tool for runners’ bodies and brains. If you don’t get enough sleep regularly, you’ll feel tired, lack energy, and your heart rate on easy runs will increase. Don’t use lack of sleep as an excuse not to jog today, but reduce your pace if necessary to stay in safe HR zones. Sleep for at least 7 hours. Permanent undersleeping could lead to accumulated fatigue, weakening the immune system, and ultimately cause injuries that are usually mistakenly associated with running but not lack of recovery.

#4 Stress

Mental health is tightly bound to our bodies’ physical health. If you are going through something unpleasant or painful in your personal life, you can notice an elevated heart rate, even on easy runs. It’s ok to use jogging as a treatment and get your thoughts in order. They say running is like meditating with your feet. In my experience, running through life’s challenging periods makes it easier and helps you find surprising solutions. However, like everything in life, don’t overdo it—even the most healthy habits can cause harm if followed fanatically.

#5 Caffeine

A cup of coffee increases the heart rate for an hour. It doesn’t mean you need to refute caffeine; keep this in mind, and don’t overload your heart. A lot of coffee can have a harmful effect—drink no more than 3 cups daily. Coffee has a dehydrating effect, so add the equivalent amount of water to your regular consumption. Also, if you want to sleep well, say no to caffeine after 6 p.m.

#6 Alcohol and Smoking

Besides being dangerous, drugs, alcohol, and smoking put additional stress on your body, elevate the runner’s heart rate level, and prevent you from progressing with running. When you’re young, it’s elementary to get on the wrong side, which inevitably leads to addictions, diseases, financial problems, and a shorter life. Make running your priority and ditch everything else that doesn’t bring you closer to your personal and professional goals.

#7 Recovering from illness and side effects from medications

A disease of any kind puts your body under stress and focuses your strength on the quickest healing. Postponing jogging and other sports until you get better is recommended. As a result, the runner can lose physical fitness and require time to return to the usual shape and performance. For example, after recovering from COVID-19, it takes 2-3 months to get back to a regular heart rate on easy runs.

Lastly, an increased HR can be a normal reaction to the consumed medications. So, decrease your effort and mileage while on medical treatment or take a break until you are completely healthy again.

#8 Pregnancy

Pregnancy triggers significant changes in women’s bodies. Supporting two organisms with a single blood system and heart puts additional stress and requires much more resources. As a result, your HR can increase even in the early stages.

So, preparing to become a mom should become your priority. Switch running to more appropriate sports, like prenatal yoga. No worries, you’ll return to jogging, regular pace, and your normal heart rate very soon.

#9 Health Pathologies

If you have gotten to this paragraph and didn’t find a decent reason for the high heart rate, chances are there might be more complicated issues related to your overall health. Anyway, consult with your doctor before continuing to run. I am firmly against self-treatment, but here is just a list of common health-related issues that could be relevant:

  • Thyroid gland temporary overload
  • Cardiac drift
  • Arrhythmia
  • Anemia

All of the reasons listed above could have unpredictable consequences. Consult a professional physician and perform a complete body examination so you will be 100% sure you are not causing any harm to yourself.

Is it OK to have a high heart rate while running?

High heart rate running is ok when anticipated, but if your HR goes up without an apparent reason and you aren’t feeling or breathing well, it’s better to stop and start over in a while.

Despite the distance you’re preparing for, a golden rule is that high HR runs should make up to 20% of your weekly distance and time. Running consistently with an increased heart rate leads to constant body exhaust because it doesn’t recover between workouts. Ultimately, you reach a plateau in your progress, get injured, or burn out.

To prevent this in the first place, buy an HR monitor and track each of your training. 80% of your monthly mileage should be under 135 beats per minute or less than 80% of your maximum heart rate. Tracking the pulse helps you better distinguish different HR zones according to your pace and perception, and you can track your pulse only once a week when you have high-intense workout training.

Running on a high heart rate

What Happens If Your Heart Rate Is Too High During Exercise For Too Long?

In a healthy and trained body running with a high heart rate for a long time will lead to the following consequences:

  1. The body will burn available energy and start to burn fat to fuel its functioning
  2. Your speed will decrease gradually while the HR remains high
  3. The body will overproduce lactate that settles in muscles and require much time to recover
  4. At best, you’ll end up being wholly exhausted—at worst, you’ll get an injury and won’t be able to jog for a while

An untrained or sick body running with a high heart rate for too long could result in loss of consciousness, heart disability, and even death. For this reason, all official races require the participants to sign a waiver of liability.

How to Lower Heart Rate While Running?

Sometimes, you need to decrease the HR immediately on long runs or between intervals. Here are a few self-tested techniques to instantly lower your heart rate while continuing running.

Deep breathing

Step 1. Deep and Smooth Stomach Breath

Breathe in as deep as you can and smoothly breathe out. This technique can lower heart rate while running by 5-10 beats per minute. If you try it and feel your body doesn’t get enough oxygen, skip it, and either slow down or finish your run.

Normal cadence

Step 2. Normalize Cadence

Running with the same amount of steps per minute helps your body stay in an efficient energy-saving mode longer despite uphills and downhills. Don’t take more or fewer steps; adapt your steps’ lengths instead—this helps you avoid sudden rises and decrease a high heart rate when running.

Slow down

Step 3. Slow down—lower your pace

If you’ve tried everything and nothing works, slow down—sometimes that is the best advice on how to lower your heart rate while running and the only way to bring your pulse back to normal.

The Bottom Line

The lower-than-usual HR on regular distances is a desirable trigger for improvement. If you experience the opposite and wonder why is my heart rate high on easy runs, something might be wrong, and you should act accordingly. Consider starting over even slower, reading additional sources, working with a professional coach, and consulting a sports physician.

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Alex Roven
Alex Roven

I completed my first 10K on a dare. In a year, I ran a half-marathon. Another year later, I finished a marathon race. Today I run 4 marathons a year and a half-marathon every week. I learned everything about running the hard way. So, I help runners achieve better results easier.