April 27, 2021

Factors That Affect Heart Rate

Your heart rate can be affected by many factors when training. To make the most of training with a heart rate monitor, you need to know what these are.

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If you’re familiar with Coached and our approach to training, you’ll probably know that we’re fans of our athlete’s training with a heart rate monitor sometimes.

Monitoring heart rate helps to ensure you do low-intensity sessions easy enough to be effective. Heart rate can be tracked against pace to monitor training progression, and most importantly, monitoring your heart rate can ensure you recover properly.

To train effectively with a heart rate monitor, it’s helpful to know what can affect heart rate during training and from session to session, so, in this article, we’ll get into it.

What Affects Your Heart Rate While Training?

Type Of Exercise

Heart rates differ between sports.

Time Of Day

Athletes training in the morning will typically see lower heart rates than what they see in the afternoon.


Your heart rate will be lower in cold weather and higher in hot weather, which may not surprise anyone living here in Singapore.


As it is for training in the heat, high humidity will affect heart rate. Heart rates rise in heat and humidity because the heart is working hard to cool the body and fuel the muscles.


When you sweat, you lose fluids, resulting in a decrease in blood plasma, making the blood thicker. Thicker blood means the heart must work harder, and as a result, your heart rate increases.


When you’re sick, your heart rate will often rise in response to the stress your body is under to fight whatever is affecting it.


If your gear fits poorly, is heavy, and you’re otherwise uncomfortable, it’s likely your heart rate will increase.

Cut Race Times, Not Corners.

Racing at your potential and enjoying training is easy when you’re following the right programme.


An inefficient technique can increase heart rate because it wastes a tremendous amount of energy.

Caffeine, Other Stimulants & Drugs

In some athletes, caffeine can raise heart rate. Over-the-counter and prescription drugs can also increase or lower heart rates depending on the drug.


If you’ve ever trained at a high altitude, you’ll have seen that heart rate is higher than at sea level. Because the air is thinner at higher altitudes, you cannot pull the same amount of oxygen in your lungs with each breath.


Most athletes will have experienced an increase in heart rate before a race. That’s because hormonal levels can affect heart rate. When you’re excited, anxious or nervous, your flight or fight hormones kick in, raising your heart rate.


Younger athletes will typically have lower heart rates than older athletes.


The cadence at which you spin your arms or legs during a swim, bike, or run affects your heart rate. A higher cadence will typically mean a higher heart rate.

A Heart Rate Monitor Is A Useful Tool

As you can see, there is a lot that can affect heart rate. For this reason, many athletes and coaches dismiss the use of a heart rate monitor calling it unreliable or not useful.

While using a heart rate monitor does come with a learning curve and can be a little tricky, I believe it’s a helpful tool to teach you how your body responds to training and other forms of stress.

By knowing the factors that affect your heart rate, you can better understand why your heart rate may be higher or lower than usual and adjust your training (or not) accordingly.

Related Articles

The Pros And Cons Of Training By Heart Rate

Why MAF Testing Is Useful (And How To Do It)

6 Common Heart Rate Training Mistakes

Ben Pulham

Ben Pulham is the founder of Coached, a personalised training programme that helps runners & triathletes optimise, track and enjoy their training.