Reserve, resting and maximum heart rate: how to calculate them?

Heart Rate: A Key Parameter for Effective Training

Philippe Propage, coach of international-level athletes, and Hélène Petot, Research and Development Engineer at DECATHLON SportsLAB and Doctor of Exercise Physiology for Performance and Health, reveal all its secrets. 

HEART RATE: WHAT YOU NEED TO KNOW

• Heart Rate (HR): This is the number of beats your heart performs in one minute.
• HRmax (maximum): The maximum number of beats your heart can perform in one minute.
• HRmax is barely impacted by training.
• HRmax decreases gradually with age (we lose about one beat per year).
• Resting HR evolves based on your physical condition: The more trained you are, the lower your resting HR will be.
• A heart rate monitor is made up of a transmitter attached with a chest strap, an armband around the biceps, and a receiver, such as a wrist device or a smartphone. The heart rate monitor is to your body what the tachometer is to your car. For runners, it measures the number of heartbeats at any given moment and prevents “over-revving.”

RESTING HEART RATE

Your resting heart rate is the lowest frequency at which your heart beats, typically between 60 and 70 beats/min on average.

• The more active you are, the lower your resting HR will be.
  For example, the lowest recorded resting HRs in humans belong to freedivers, around 25 beats/min.
• Conversely, if you are sedentary and/or lack physical activity, your resting HR will be higher. It is also influenced by stress and risk factors (smoking, alcohol, genetics), which can increase it.

Good news: Regular training can lower your resting HR, so it’s never too late to improve!

When to measure it?
The most accurate time to measure your resting HR is when you are at your calmest and most relaxed. This is usually in the morning, while still in bed, before getting out from under the covers.

How to measure it?

• Option 1: If you have a heart rate monitor, record for 5 minutes and take the average. Repeat this for 3 mornings and calculate the overall average.
• Option 2: Without a monitor, place three fingers on your carotid artery (in the groove under your chin, to the side) to feel your pulse and count the beats. Count the beats for 15 seconds and multiply by 4. Repeat three times and calculate the average.

Reminder: To ensure accuracy, measure your resting HR in the morning. If you’re reading this article at 3 PM at your desk, the HR you measure will likely be low but not your true resting HR.

MAXIMUM HEART RATE

Your maximum heart rate corresponds to the highest frequency at which your heart can beat.

How to measure it?
There are four methods:

1. The Astrand Method:

   • For women: $226-\text{your age}$.
   • For men: $220-\text{your age}$.
     Example: A 40-year-old woman: $226-40=186bpm$.
     While simple, this method is theoretical and may not apply to everyone.

2. The Gellish Method (2007):

   • If aged between 35 and 65 years:
     HRmax=191.5−(0.007×age2)HR_{\text{max}} = 191.5 - (0.007 \times \text{age}^2)HRmax​=191.5−(0.007×age2).
     Example: A 48-year-old: 191.5−(0.007×482)=175bpm191.5 - (0.007 \times 48^2) = 175 bpm191.5−(0.007×482)=175bpm.
   • If younger than 35 years:
     HRmax=206.9−(0.67×age)HR_{\text{max}} = 206.9 - (0.67 \times \text{age})HRmax​=206.9−(0.67×age).
     Example: A 28-year-old: $206.9-(0.67\times 28)=188bpm$.

3. Field Test:
   After a 20-minute warm-up, increase your pace in increments of 100 meters or 30 seconds until you reach your maximum capacity (give it your all!) over 1000 meters or 4 minutes. The HR displayed on your monitor at the finish will be a good estimate of your HRmax.

4. Professional Test:
   A sports cardiologist can perform a test to determine your precise HRmax.

HEART RATE RESERVE

Now let’s talk about your heart rate reserve, as this is the basis for calculating training intensity.

Your heart rate varies between your resting HR and your HRmax.

Example:
Charles, 39 years old, has a resting HR of 65 bpm and an HRmax of 181 bpm. His heart can beat within this range, meaning his heart rate reserve is:
$181-65=116bpm$.

This reserve increases or decreases depending on your training level, mostly influenced by a decrease in resting HR.

How to use it in training?
Heart rate is proportional to exercise intensity. To plan your session’s intensity, you can reverse the logic: calculate the HR you need to maintain based on your session’s planned intensity using a percentage of your heart rate reserve.

Example:
Charles plans a jogging session at 65% of his heart rate reserve:
HRsession=(65×116100)+65=140bpmHR_{\text{session}} = \left( \frac{65 \times 116}{100} \right) + 65 = 140 bpmHRsession​=(10065×116​)+65=140bpm.

Now you know how your program calculates your session intensity!

See you soon on Decathlon Coach!