Sorry, Strength Training Is Not Considered a Zone 2 Exercise.

Heart rate zones are all the rage in the fitness world these days, and any smartwatch or fitness tracker will happily tell you what “zone” you’re in when you do a workout—any workout. Even strength training. Even yoga. So you might be tempted to interpret this data in terms of the benefits of training in zone 2 . If my heart rate is in zone 2 when I lift weights, that means I just spent an hour training in zone 2, right? Unfortunately no.

Heart rate zones are designed for cardio.

The idea of ​​dividing your heart rate into “zones” came from cardio training. In fact, the very idea of ​​heart rate monitoring for sporting (rather than medical) purposes originated with the Finnish ski team and then spread to other athletes. Your heart rate can tell you how hard you are working compared to your past performance, and you can use this information to evaluate whether you should work harder or easier. Or, as Finnish triathlete Pauli Kiuri is quoted in an article in Polar magazine : “At some point during a run you get the feeling that you can’t go any further. But if your rate is still only 160 beats per minute, you just have to believe that yes, you can!” (Polar was the manufacturer of these first heart rate monitors.)

Heart rate training makes sense for endurance sports because the harder you work, the faster your heart beats. So you can use this relationship in reverse: the higher the number on your heart rate monitor, the harder you have to work. Your heart rate is a good indicator of the work you are doing.

But this relationship with heart rate does not extend to other types of exercise. Your heart rate during yoga does not indicate how deeply you are stretching. Your heart rate during strength training doesn’t tell you whether you’re lifting light or heavy weights. This is why heart rate doesn’t matter during strength training .

Heart rate zones tell you what your whole body is doing, not what your heart is doing.

Heart rate, when used correctly, is a so-called indirect indicator. We don’t track heart rate because heart rate matters; We track our heart rate because it tells us something else important—in this case, the intensity of our cardio exercise.

We get certain benefits from zone 2 cardio: burning calories without fatigue , increasing mitochondrial and capillary density, and improving VO2max , to name a few. These benefits come from the fact that our entire body is doing the exercise.

Our muscles are constantly contracting, which requires our mitochondria to work harder to fuel them. These mitochondria need more fuel, so our cells become more sensitive to insulin and can absorb sugar from the blood more efficiently. To do all this, we need more nutrients and oxygen to reach our muscle cells, so we grow more capillaries to supply them and remove metabolic byproducts.

This big picture is what Zone 2 training is all about. Simply increasing your heart rate without doing all these other things will not lead to good adaptation in zone 2.

This is why sitting through a stressful meeting at work for 30 minutes is not the same as going for a run. Watching a horror movie is not the same as doing a HIIT workout. And unfortunately, sauna lovers, the sauna is not a substitute for exercise . (Sauna sessions seem to improve the health of your blood vessels somewhat, but they don’t do everything else.) When you think about it, cardio zone 2 has a lot more in common with zone 3 (or even zone 5). ) cardio than “zone 2” lifts.

What zone should strength training be in?

Tricky question! Zones don’t matter for strength training. There are many ways to gauge how hard you’re working when you lift weights, but none of them involve using a heart rate monitor. Here are some common ways to evaluate your efforts:

• Compare the weight on the bar to the heaviest weight you’ve ever lifted : for example, you can squat 80% of your maximum.

• How many reps do you do at a given weight : Five reps at 80% are harder than one rep at 80%.

• How fast you move when performing a rep : the harder it is, the slower it will move; there are even gadgets to measure this. This property is sometimes called “bar speed”, as in how fast the bar moves.

• How many more reps do you think you could have done : If you had three reps “under your belt”, this is an easier set than if the last rep you did was the last rep you could do.

• How sore, tired, or “pumped” a muscle is: In some training styles, this can help you determine how much work the muscle group received during the day’s workout.

Some things that don’t correlate with how much strength you build include how out of breath you are after a set of exercises or how fast your heart beats during or after exercise.

The truth about heart rate when lifting weights is that your heart rate can be higher, your breathing heavier, and your rest time longer if your cardio training is poor . This is a sign that you might want to improve your fitness by doing real cardio (Zone 2 or otherwise) so that you get those adaptations and don’t have to sit and suck the wind for long periods of time between sets. But your cardio training only plays a supporting role here; it is not a strength training goal and is not a useful metric for assessing your effort.

Or to put it another way: when you perform five sets of five squats at 80% of your maximum, you get the same strength gains whether you do it with three minutes of rest and a smile on your face or with eight minutes of rest and a smile on your face. sky-high pulse.

Okay, but what are the normal zones for strength training?

In fact, you will see your heart rate jump up and down during strength training. During rest, your heart rate may be in zone 1 or 2; During short bouts of exercise, you may notice your heart rate spike to zone 3 or higher.

You’ll most likely notice a higher heart rate during sets of many reps (sets of 10 reps may result in a higher heart rate than sets of three reps). It doesn’t really matter what heart rate zone you’re in.

The only thing that really matters, if you check your heart rate graph afterwards, is that your strength training has peaks and valleys. If it looks relatively flat, you may not be getting enough rest . For comparison, here are my graphs for a recent run (upper zone 2/lower zone 3) and a strength workout that included snatches, deadlifts, and squats. Notice the longer pauses and higher lifts towards the end of the workout when I was squatting heavily for six reps at a time.

If zones don’t matter, why does my app tell me what zone my strength training was in?

The short answer is because they can, not because they have to.

When endurance athletes first started training with heart rate, it was a replacement for running against the clock or just by feel. They realized that it was an indicator of how hard their entire body was working while running or skiing.

It’s different in the modern era, where every watch measures your heart rate. The truth is that heart rate zones are present on all results screens because your watch easily measures your heart rate, the zones are easily calculated by your app, and because the company that makes the app and watch wants to please you with a whole bunch of cool graphs after each workout.

Heart rate zone graphs make your workout more meaningful, and viewing them is like a little reward sticker that will help you maintain the habit (and, from the company’s perspective, using its product). Enjoy the graphs if they look pretty, but keep an eye on the important metrics, which for strength training include almost everything except heart rate.

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