Why Is My Heart Rate High On Easy Runs? 8 Reasons + Solutions

‘I’m taking it gentle and slow, so why is my heart rate high on easy runs?

Training using your heart rate as an effort indicator can be beneficial during certain phases of your running program.

However, it’s important to keep in mind that your heart rate can fluctuate due to a variety of different factors which can provoke a sense of uncertainty in your effort levels.

Your heart rate can rise during long runs for various reasons, so it’s reassuring and helpful to know the possible sources of these fluctuations.

Knowing the possible reasons behind high heart rate runs not only means you can then identify solutions, but also allows you to decide the best effort measure for you – whether it be sticking to heart rate data or swapping to specific paces or rate of perceived exertion.

In this article, we will discuss:

  • 8 Everyday Factors That Increase Your Heart Rate On Easy Runs
  • How To Minimise The Effects Of These 8 Factors To Help Lower Your Heart Rate Whilst Running
  • How To Use Rate Of Perceived Exertion Instead Of Heart Rate Data When Training


Let’s talk heart rates!

A lady checking her pulse wearing running gear in the woods

Factors That Increase Your Heart Rate

Let’s shed some light on as to why your heart rate is fluctuating so much on your long runs with these 8 influences.

We’ll begin by looking at how mother nature can affect our heart rate on our long runs, whether it be because of the terrain type, course or climate, and see what we can do about it.

#1 High Altitude

When running at higher altitudes, there is less available oxygen for you to consume resulting in higher heart rate.

The more difficult it is for your body to transport oxygen to your muscles, the harder your body has to work, resulting in an increase in your heart rate

Not only will high altitude long runs affect your heart rate, but they will also alter your breathing. Less pressure hinders oxygen from getting to your lungs as effectively as at lower altitudes, resulting in labored breathing. 

This is a pretty tricky factor to control as your body will need to acclimatize properly to decrease these effects. To do so, you will need a minimum of a few days, ideally a couple of weeks, for this process to be successful.

a lady running next to snowy mountains

#2 Heat and Humidity

Running in hot and humid weather can significantly affect your heart rate. As your body temperature rises, your body responds by wanting to cool itself down. 

When the humidity is high, it makes it even more difficult for your body to cool itself off.

Heavy moisture doesn’t allow your sweat to evaporate into the air quickly as in drier weather. Putting your system to work harder in these conditions will result in a rise in your heart rate. 

To keep your body cool, apply cold compresses or ice to the back of your neck. If you are running trail, take advantage of every river you pass by dipping in and cooling yourself off.

You’ll lower your body temperature along with your heart rate and feel revived and ready to continue.

Related: Average Heart Rate While Running: Guide By Age + 7 Influencing Factors

the silhouette of two people running against a white and blue background

#3 Dehydration

Dehydration goes hand in hand with hot and humid climates but doesn’t exclusively apply to those conditions.

Yep, you can also become dehydrated in colder climates where your main focus is not usually on your hydration.

The early signs of dehydration are more difficult to detect in cooler drier weather due to the fact that the running conditions are more comfortable.  

In a 2010 study from the Journal of Athletic Training, “when running in the heat, your core body temperature increases along with your heart rate (3 to 5 beats per minute) for every 1% of body mass loss.” Blood volume decreases, causing a rise in heart rate.

Dehydration not only raises your heart rate but can affect your running in other ways, such as lethargy, slower paces, headaches, and cramping. It can become dangerous if not dealt with promptly and precautions should be taken to avoid it altogether. 

Stay well-hydrated before, throughout, and after all of your long runs. You can calculate your fluid loss per hour with this sweat test.

a lady wearing running gear drinking water in a rocky desert environment

#4 Difficult Terrain

Why is my heart rate high on easy runs? Well, it could be the terrain.

Even on an easy long run, tricky terrain and hilly courses can affect your heart rate. Even when trying to keep your run comfortable, changes in terrain can recruit other muscles to work, and work hard they will. Getting oxygen to these muscles will raise your heart rate and make it more challenging to stick to an easy pace.

When the terrain gets tough, slow down to try and avoid increasing your effort level. If you are running on trails and encounter steep hills, don’t feel like you have to run them. Hike up them to maintain a comfortable heart rate, and then begin to jog again when you reach the top.

#5 Cardiac Drift

Have you ever wondered why your heart rate begins to gradually increase during a long run even though you are sticking to the same pace, effort, and breathing rate? This is the famous cardiac drift

So, what happens? 

Again, a rise in body temperature and fluid loss. Your body starts to increase skin blood flow as it tries to cool itself down, which brings your heart rate right up. This can begin as early on as 30 minutes into your long run. 

Keeping cool and staying hydrated are a couple of ways to help assist in controlling this rise in heart rate. 

The next factors we are going to discuss are causes that we can attempt to control a bit better than the weather and terrain. Adjusting some of your daily routines could help curb the effects. Let’s take a look.

a man running in nature checking his watch

#6 Lack of Sleep

Being overtired from not getting enough sleep can not only affect your training in general but will also raise your heart rate 5-10 beats per minute on your long runs. 

As athletes, you need to ensure you get enough sleep. The minimum number of hours rises the more seriously you take your running. On average, athletes should get between 7-9 hours of sleep, and elites, a minimum of 9 hours

It can be challenging to get the necessary amount of sleep, but we’ve compiled some tips to help you achieve it.

Establish a specific bedtime and a pre-sleep routine to wind down and relax. Diffuse essential oils such as lavender to help you calm down, turn off all devices to limit distraction, and be sure you are comfortable

Listen to a bedtime meditation exercise or a deep sleep music mix that can help stop your mind from racing and lead you into a comfortable, deep sleep.

a lady sleeping

#7 Stress

Another factor that can increase your heart rate during your long runs is stress. This will not only increase your heart rate while you run but during any moments during the day when your stress is getting to you.

Even though exercise is one of the best stress relievers, life has a way of piling on other sources of stress.

If your mind begins to race during a long run, your heart rate will most likely race along with it. 

To minimize stressful thoughts, try running with friends and have a friendly chat as you go to get your mind off your troubles. If you run alone, you could listen to your favorite music or a podcast to distract yourself. 

Reducing your stress level will help keep your heart rate in check and make your runs more enjoyable.

two women running on a road with mountains behind

#8 Fatigue

Overtraining and fatiguing your body can also affect your heart rate during your long runs. However, it is more noticeable in your resting heart rate.

Suppose your resting heart rate is higher than usual, and your body doesn’t respond accordingly during your training sessions. In that case, you may want to think about taking a break and letting your body recover so you can come back stronger for your future sessions.

As these 8 factors show, there are many reasons why your heart rate may be higher that expected during your long runs, as many of these factors are obstacles we face every day. 

If you are affected by any of these 8 factors on a given day, you may want to take a look at using your perceived rate of exertion for that long run to avoid running slower than you wish to.

a lady in running gear bent over with her hands on her knees

Rate of Perceived Exertion (RPE)

What should you do if you have a high heart rate when running but feel fine?

Well, it is normal to have a relatively higher heart rate while exercising, and sometimes, it may actually be better to focus on how you feel.

Using the following chart, you can carefully analyze how you should feel for each type of workout. As we focus on long runs in this article, a RPE of 2-3 should be appropriate for your session

If your heart rate is off the charts, yet you feel you are “able to maintain a conversation” while running, you may want to stick with your RPE chart for now. 

If your heart rate is high due to any of these factors, don’t let your bpm or specific paces hold you back. Data is helpful as we can analyze endless aspects of our training; however, the way you feel at times can be a better guide to help you get the most out of your workout.

In fact, you may find that by paying attention to your RPE, rather than focusing on your heart rate, you will lower your heart rate while running because you making sure not to push your body too hard.

If cardio-wise and exertion-wise you feel fine, but you still think that your heart rate is higher than it should be, it might be worth checking up on the other causes of high heart rate whilst running mentioned in the article.

Whilst it is normal to have a higher heart rate whilst running, if in doubt, there is never any harm in seeing a doctor if something seems unusual.

an RPE chart showing the different workout intensities

To Summarize: Here’s How To Help Lower Your Heart Rate Whilst Running

By following these tips, you can help to keep your heart rate down while running:

  • Take care when running at high altitudes
  • Stay cool when running in hot and humid environments
  • Keep hydrated
  • Take it easy when running on difficult terrain; don’t feel like you have to run up every hill
  • Make sure you’re sleeping well
  • Try to minimize stress
  • Avoid overtraining
  • Pay attention to your RPE (i.e. don’t focus too much on the stats, but rather focus on how you feel)

Why is my heart rate high on easy runs? Answered. But what About heavy legs?

So, you’ve learned about high heart rates, but what about heavy legs when running?

Need help? Check this out: Legs Feel Heavy When Running? Here’s 7 Reasons Why.

Photo of author
Katelyn is an experienced ultra-marathoner and outdoor enthusiast with a passion for the trails. In the running community, she is known for her ear-to-ear smile, even under the toughest racing conditions. She is a UESCA-certified running coach and loves sharing her knowledge and experience to help people reach their goals and become the best runners they can be. Her biggest passion is to motivate others to hit the trails or road alongside her, have a blast, and run for fun!

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