Should You Train with A Power Meter or Heart Rate Monitor?

By : Mr Mamil
Updated :

This site is supported by its audience. We may earn an affiliate commission when you purchase through links on this site.

Now you’re ready to get back on board using technology to improve your performance, but you aren’t sure if a heart rate monitor or a power meter is the answer.

Or maybe both?

  • What’s the difference between heart rate and power?
  • Is one a better choice?
  • And how much will it cost?

Ideally, you want to train with both power and heart rate as they give you the complete picture of your training.

The table below shows a quick summary and comparison between training with power vs heart rate.

PowerHeart rate
CostCosts from $300 upwardsCosts below $100
Pacing toolVery reliable, the gold standardNot as reliable due to HR lag
Learning curveSteep learning curveQuick and easy
Training metricsMany metrics Straightforward and easy to understand
External factor influencePower numbers are absolute, regardless of external factorsHR readings can vary
Power vs heart rate training

Training with heart rate pros

Heart rate monitors pick up your heartbeat through electrical signals sent to a measuring device like a watch, strap, or other smart devices. How the signal is registered varies, but the most accurate among them is using a strap for its large surface area and proximity to the heart.

Affordable for most cyclists

It’s not news that first and second-generation tech devices cost a bundle. Such was the way of the heart rate monitor, but one of its major advantages today is its affordability.

A dependable heart rate monitor costs well under $100, a sum attainable by most cyclists.

Many heart rate monitor models are available today from leading brands such as Polar, Garmin, and Wahoo.

Easy-to-understand metrics

HR ZoneIntensity% of HRmax
1Very light50 – 60%
2Light60 – 70%
3Moderate70 – 80%
4Hard80 – 90%
5Maximum90 – 100%
Heart rate training zones

Heart rate monitors are best on prolonged efforts, like long uphill climbs and time trials. You don’t need an advanced degree to read and understand the data a heart rate monitor provides. Once you’ve established training zones based on maximal effort, you’ll see how fast your heart beats during exercise.

The established heart rate zones guide your exercise intensity based on your training objective.

The resulting data also tips off which energy source you use in each zone. The higher the heart rate, the greater the calories burned as carbohydrates vs fats. If your goal is burning fat and calories to lose weight, you can ride in Zone 2.

Training with heart rate cons

While there are many benefits of training with a heart rate monitor, there are disadvantages too.

Heart rate lag and external influences are two primary disadvantages.

Susceptible to heart rate lag

A heart responds to changes in exercise intensity, but that isn’t immediate.

The delay is known as Heart Rate Lag, which can be anywhere between 30 to 180 seconds, depending on the intensity.

The lag means that training with a heart rate monitor isn’t practical for evaluating high-intensity intervals of one minute or less. The same lag applies when the effort ends, so take a few extra moments during recovery to reach your base before starting again.

Easily affected by external factors

Another drawback to training by heart rate is how other factors influence your heartbeat. The data shown may not be an accurate depiction of your actual state.

Heart rate varies on many things, such as how much caffeine you drank, if you’re dehydrated, overtrained, lacking sleep, jet-lagged, and even based on the weather and ambient temperature.

While heart rate monitors remain an excellent training tool, they must be used in situations that complement their advantages and limit their disadvantages.

They are best reserved for extended exercise efforts with fewer rate fluctuations, like long and steady hill climbs or time trials, and not for high-intensity intervals (HIIT).

Training with power pros

While a heart rate monitor shows you what’s happening to your body, a power meter displays the result of your efforts and your output in real time.

One significant advantage to training with a power meter is the lack of external influences on the results. What you see is what you get. This rapid return of data comes in handy for longer and shorter, high-intensity intervals, allowing you to fine-tune your training while providing a treasure chest of insight to comprehend your strengths and weaknesses.

Power numbers are absolute

SRM PC8

The watt is the most accurate means of measuring effort; 250w is 250w. They represent how your body responds to increased or decreased effort related to heart rate.

Power is absolute and not affected by a lag in response.

If you’ve accurately established your Functional Threshold Power (FTP), the power zones are more reliable and useful when using a power meter for training.

The accuracy of the data means you’ll reap the most benefit from your training.

Quantifiable results

The power meter was once a tool reserved for professional cyclists with a price to match. Today, they are more affordable and indispensable for cyclists who want to train efficiently.

Take the guesswork out of your training with quantifiable results.

A quality power meter provides accurate, dependable data to assist your training.

The major differences between power meters are their accuracy (1% vs 2%) and design (left crankarm, crankset spider, pedals). One might not be much better than another, but take the time to compare brands and models before purchasing.

Excellent pacing tool

Power meters are fantastic pacing tools and ideal for less experienced cyclists.

Once you’ve established your Functional Threshold Power (FTP), they will prevent you from going too hard too soon, so you can say goodbye to blowing up on the hill or not making it to the finish line.

When paced correctly, with the help of your meter, you’ll theoretically flatten out any ride as your effort will be more consistent over the course length, regardless of the terrain.

The power meter’s pacing capabilities are especially practical for time trials and sportive events.

Less susceptible to external influences

Many external factors can affect heart rate, but this is not the case with a power meter.

Power is the most reliable measure of exercise intensity over heart rate or perceived exertion alone.

The power data isn’t compromised by factors such as fatigue, environmental conditions, or dehydration.

Training with power cons

There are many benefits to training with a power meter; however, it’s important to note they have a few disadvantages too. Cyclists may become data-obsessed, which can lead to overtraining.

Or less time is spent enjoying the ride or beautiful scenery as they are fixed on their head unit.

Steep learning curve

A Performance Management Chart

Today’s power meters offer enormous amounts of information that can be challenging to interpret, especially for beginners.

Not everyone is comfortable with technology; it takes time to learn and understand power terminology, data, and the software that analyzes it.

There are many metrics, such as Average Power, Normalized Power (NP), Training Stress Score (TSS), and Intensity Factor (IF), among others, to interpret.

But without this data, riders may not get the most out of their investment nor improve their training and performance.

Power meters cost more

A decade ago, only professional cyclists used power meters because of their high cost, leaving them out of reach of the general public.

Things have changed, and prices have come down considerably. While power meters remain more expensive than heart rate monitors, many entry-level models are available for $200 to $400.