Categories: Train
Tags: cycling

A holistic approach to cycling with power and heart rate

March 27, 2018

When power meters became part of main stream cycling more than a decade ago, many athletes tossed their heart rate monitors to the side in favor of new technology. Cycling power meters were dubbed by many as being more accurate, better for pacing, and easier to use for tracking fitness gains.

While it’s true that heart rate data can be affected by variables such as core temperature, fatigue, hydration, and stress, has this “old school” training tool really become useless in today’s modern peloton?

I sat down with Polar Cycling Product Specialist and power meter expert Jason Crowe to discuss the differences between power meters and heart rate monitors and how they can and should be used together in cycling.

The Value of Power

Whether you’re riding on a flat road in the middle of winter or going up a mountain in the summer, cycling power meter metrics provide you with a way to measure your effort regardless of terrain, weather, or any other physiological factors.

It’s also used by many to gauge the overall strength of one rider when compared to another by calculating wattage output per kilogram of body weight.

Power meters and wattage metrics are a reference to muscular workload.

“Power meters and wattage metrics are a reference to muscular workload,” Crowe says. “Just as you go into the gym to push a certain number of kilos, cycling power will give you an idea of how hard you are pushing on the bike. When you train with power, it is specific training for the muscles. Watts are a constant value, just as the weights are on a bench press.” 

Gauging power numbers is one way to easily test your fitness gains for short periods of time.

If you follow the professional peloton, you’ll see lots of power meter metrics being thrown around. Bradley Wiggins can put out 450 watts on a 30-minute climb, and Mark Cavendish has been known to reach outputs as high as 1,500 – 1,800 during a sprint.

For many cyclists, gauging these numbers during their own training rides and races is one way to easily test their fitness gains for short periods of time when outside variables can be minimized.

The Importance of Heart Rate

While the value of heart rate monitors has been minimized by many cyclists who favor power meters, according to Crowe the “one is better than the other” philosophy is a flawed concept.

A watt is a watt, but the physiological cost of the watts you produce can vary.

“You hear cyclists say a lot that a watt is a watt. While this is true, the physiological cost of the watts you produce can vary. Holding 250 watts up Mount Ventoux after several easy days of riding is not the same as holding the same average power on day 15 of the Tour de France,” Crowe explains.

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“I like to compare it to running your dishwasher or washing machine at home. For most people, you run your appliances at night as opposed to during the day when the cost of electricity is less. You can think of the watts you produce on the bike the same way. Monitoring your heart rate allows you to see what it costs physiologically to produce those watts, and it’s not always the same.”

“Power is a very specific indication of the workload on your leg muscles, whereas the heart rate is an indication of the condition or state of readiness of your body as a whole.”

Your body’s response to the stress of exercise will directly impact your performance on the road. By measuring heart rate data during your daily workouts, you can monitor signs of overtraining, how recovered you are from the previous day’s efforts, and other signs of fatigue that could be related to lack of sleep or stress that you won’t get if you are relying solely on power meter metrics.

“Power is a very specific indication of the workload on your leg muscles, whereas the heart rate is an indication of the condition or state of readiness of your body as a whole,” Crowe says. 

Why power and heart rate make a great team

For athletes who are serious about performance and looking to see improvement in their training and racing, it’s important to look at power and heart rate as two pieces of a much bigger puzzle.

“For cyclists, you need to gather as much information as possible. Heart rate, power, cadence, sleep, nutrition, the weather, stress levels, and the time of day you train are all part of understanding your body, how it reacts to the stress of training, and the various stimuli in our environment,” Crowe explains.

Only looking at one metric, or valuing one more than the other, can often lead cyclists to overtraining or injury and negatively impact training.

Only looking at one metric, or valuing one more than the other, can often lead cyclists to overtraining or injury and negatively impact training.

“If you look only at cycling power, then you will miss the fact that your body is having to work more or less to produce the given workload. The result of this is that you will end up digging yourself into a very deep hole that can be very difficult to get out of,” Crowe says.

If you see that your heart rate is not rising normally, that can be a sign that your body is tired and unable to perform the desired workload.

“Conversely, if you see that your heart rate is not rising normally, that can be a sign that your body is tired and unable to perform the desired workload. A good rule of thumb is that if you have to work much harder than normal to get your heart rate up to normal levels, then it’s probably best to get some rest.”

As athletes, it is important to remember that we are all different and subject to our own daily fluctuations. How tired you are, your level of motivation, or expectations placed on you by others or even yourself can alter your physical abilities from day to day.

This is why taking a more holistic approach to training and racing by gathering as much information as possible as it relates to heart rate, power, and other metrics is important in order to understand the bigger picture.

“The beauty of training is that it’s more art than science,” Crowe says. “Even though the general physiological principles apply to everyone, we all respond individually.”