Cycling Training with Power vs Heart Rate – Which is Best?

Are you ready to bring your training to the next level? Of course you are. And to do that, you’ll want to know the difference between training by heart rate versus by power meter (you will!). Well look no further, I’m here to explain both, and help you decide which one (or both, or neither!) is best for you.

Cyclists in general are a bunch of data nerds. While we certainly love the wind in our hair, sometimes it’s all about being King (or Queen) of the Mountain on Strava. And Kings and Queens know all about power.

Chances are you have at least a basic bike computer. You’ve been tracking your speed, cadence, and distance for sometime. There’s nothing more exciting than telling your riding mate that you averaged 45 km/hour on your recent ride (Monty: bloody hull, averaging 45km/h!).

Speed is an important training metric, but at the end of the day, it’s just not that accurate.

Speed has many external variables that affect it, from road incline, wind speed, rider weight, and tire width. If you’re looking to upgrade your training program than it’s time to consider investing in either a heart rate monitor or power meter or maybe both.

Both devices, especially power meters, can be big investments. So which is best – power meter or heart rate monitor?

What is heart rate training?

Heart rate training involves using a heart rate monitor to train in specific zones to improve your speed, fitness, and body composition. If you’re looking to take your training to the next level, purchasing a heart rate monitor is the next natural step.

Heart rate monitors are relatively cheap. Your bike computer might already be capable of reading and tracking heart rate. If that’s the case then you just need to purchase a compatible heart rate strap. If not, it’s time to upgrade your bike computer to a model that can read heart rate.

Many cyclists track heart rate already, but very few know what the numbers actually mean. Some cyclists even love bragging about how high they got their heart rate in their recent ride. But, that’s not the goal of heart rate training.

By training in specific heart rate zones, you can increase your endurance, speed, and strength on and off the bike. In order words, you can become a stronger and more efficient cyclist.

What is power training?

A power meter is one of the best investments you can make in terms of your training. And, an investment it is. Power meters are expensive, although prices have been decreasing over the years with new technology.

A power meter is a device that attaches to your crankset, wheel, or pedal axle that bends when you push down the pedals. A strain gauge then coverts this flex into electrical resistance that is sent to a computer and read as torque. Torque is simply how hard you are pushing on your pedals multiplied by your cadence.

Power meters are essentially truth meters. They tell you how hard or easy you are working in a quantitative number. Similar to heart rate training, you train in specific power zones to increase your strength, speed, and overall cycling fitness. Almost all professional cyclists train with power meters today.

What’s the difference between power vs. heart rate training?

Power and heart rate tell you two different things. Power measures the amount of work you are doing or simply your output. Heart rate measures your body’s response to your effort or its input.

Power meters don’t lie. Heart rate can. Heart rate can be affected by numerous external factors, like fatigue, temperature, and hydration. Additionally, there is a lag time in heart rate response due to exertion change. For example, your heart rate will not rise until you’re about 15 to 30 seconds into your hill climb.

Despite the disadvantages of training with heart rate, heart rate training is still beneficial. Heart rate training allows you to track your fitness over time. It’s also useful to spot overtraining as one of the main telltale signs of overtraining is a higher than usual resting heart rate that lasts for several consecutive days.

How do I train with power or heart rate?

Heart rate and power specific training is similar. Both work towards the same goal – a stronger and fitter cyclist – through targeting specific training zones. Training zones refer to the intensity in which you are riding. Different training zones bring about different physiological adaptations therefore allowing you to target specific improvements to your cycling fitness, like endurance or anaerobic power.

Training zones vary slightly depending on the model, but they are essentially the same. Training zones are broken down below for both power and heart rate.

ZoneFitness Target% Max HR% FTP Power
OneActive Recovery50-60%Less than 55%
SevenNeuromuscular Power100%Greater than 150%

Each zone has a specific purpose that aims to induce a specific physiological reaction in your body to improve your overall fitness. As long as you train using zones, the device that you use doesn’t really matter.

What does each training zone mean?

Zone 1 (Active Recovery) – Zone one is an easy pace that allows you to stay active without becoming fatigued. It is used mostly during recovery rides and between hard intervals.

Zone 2 (Endurance) – You’ll spend most of your time here as zone two teaches your body to burn fat as fuel and produce more mitochondria, the part of the cell that produces energy.

Zone 3 (Tempo) – Zone three is a moderate pace that feels slightly hard, but can be ridden comfortably for an extended time. Zone three stimulates your body to increase glycogen storage, but also induces fatigue.

Zone 4 (Threshold) – Your body starts to switch from aerobic to anaerobic energy. Zone four produces a large amount of lactic acid so your body can learn how to metabolize it for energy.

Zone 5 (VO2) – Zone five is a pace that you can only hold for about three to eight minutes. Your legs will feel like they are on fire. Zone five aims to increase your cardiac output so your heart can pump more blood to your muscles.

Zone 6 (Anaerobic) – Zone six is maximum effort. It can only last for up to three minutes before you fatigue. Zone six is used mostly when you’re trying to attack during a race.

Zone 7 (Neuromuscular Power) – Zone seven is another maximum effort pace that only lasts for under a minute. It is used to increase muscle size and power. Think sprint power.

So, which is better power or heart rate training?

The right answer is both if you can afford it. Unfortunately, due to the cost of power meters, it’s not realistic for many cyclists. Remember that power meters measure output whereas heart rate monitors measure input. Both are helpful devices to improve your overall cycling fitness.

If you must choose one, start with heart rate monitor as heart rate specific training will improve your overall cycling fitness. As you’re training you can start to save up for a power meter if you choose to go that route. Once you have a power meter, you can start training in power zones. But keep your heart rate monitor, as it will help monitor your body’s response to producing power and fatigue levels.

About the author

Katelyn Michaud is an American roaming in Australia. Having not ridden a bike for over 15 years, she purchased her first road bike in 2008 because “cycling looked fun”. Whilst she has dabbled in the dark side (triathlon), she remains a passionate road cyclist. Katelyn is a certified USA Cycling Level III coach, USAT Level I Triathlon coach, and personal trainer specializing in endurance athletes.  

Monty - Sportive Cyclist
Monty is an enthusiastic road cyclist with only moderate talent. He started Sportive Cyclist in 2013 to record the journey to his first 100 mile ride, the RideLondon 100. Over time the blog has expanded to include training advice, gear reviews and road cycling tales, all from the perspective of a not-very-fit MAMIL. Since you're here, Monty would also like you to check out his YouTube channel. Also, Monty really needs to stop referring to himself in the third person.

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