- Age-based formulas for maximum heart rate can be well off for individuals.
- A field test for threshold heart rate gives you far more useful numbers.
- Keep most of your training easy and a smaller share properly hard.
- In a race, use heart rate as a ceiling in the first half, not a target.
- Chest straps are more reliable than wrist sensors during HYROX-style work.
Why heart rate is useful for HYROX
Heart rate gives you an objective view of how hard your body is working. That helps in two big ways. In training, it stops the most common endurance mistake: running every session at the same moderately hard pace, too hard to recover from and too easy to push your top end. In racing, it gives you an early warning that you are going out too fast.
It is not perfect. Heart rate lags behind effort, drifts upward over long sessions and is affected by heat, caffeine, stress, poor sleep and dehydration. So think of it as one tool among three: heart rate, how you feel and your pace or power. Used together, they give you a clear picture.
It is especially helpful for people new to endurance training, who tend to have one speed: fairly hard. Seeing the numbers makes it obvious when an easy run is not easy, and that single change often improves fitness more than any new session.
Finding your real numbers
The classic formula of 220 minus your age gives a rough estimate of maximum heart rate, but individual values can be well above or below it. Zones based on it can be badly wrong for you, making easy sessions too hard or hard sessions too easy.
A better approach is to find your threshold heart rate: roughly the highest heart rate you can sustain for an extended hard effort. A common field test is:
- Warm up well for 15 minutes.
- Run, row or ride as hard as you can sustain for 30 minutes, evenly paced.
- Take your average heart rate over the final 20 minutes. That is a good estimate of your threshold heart rate.
- Cool down for 10 minutes.
Do the test on fresh legs and repeat it every couple of months, as your numbers will shift with fitness. Running threshold is usually a little higher than rowing or cycling threshold, so if you train on several machines, expect slightly different numbers for each.
Simple zones that are good enough
You do not need a complicated system. Three or five zones, described in plain terms, work well:
- Easy: comfortably below threshold. You can talk in full sentences. Most of your running and engine work lives here.
- Moderate: noticeably harder, but still controlled. Useful in small doses, easy to overdo.
- Threshold: around your threshold heart rate. Comfortably hard, the effort you could hold for about an hour. Tempo runs and longer intervals.
- Hard: above threshold. Short intervals of a few minutes or less.
- Maximal: all-out efforts, rarely needed in HYROX training.
If you prefer percentages, easy work is typically well below threshold heart rate, and threshold sessions sit at or just under it. The labels matter less than using them consistently.
Balancing easy and hard sessions
Endurance research and coaching practice have long pointed to the same pattern: most training should be easy, with a smaller share genuinely hard. Many coaches use a rough split of around 80 percent easy and 20 percent hard. For a HYROX athlete training four or five times a week, that usually means one or two hard sessions, with the rest easy or strength-focused.
Heart rate makes this practical. On easy runs, keep your heart rate in the easy zone even if that means running slower than your ego would like, or walking up hills. On hard days, make sure you actually reach threshold and above. If you are new to structured cardio, the guide to cardio for beginners is a gentler starting point.
Heart rate during a HYROX race
In a race, heart rate climbs steadily over the course of the event, spikes on the SkiErg and burpee broad jumps, and may dip slightly on the row or farmers carry. By the lunges and wall balls, most people are working near their highest sustainable level.
The most useful way to use it is as a ceiling in the first half. If your heart rate is already well above threshold on the first or second run, you are almost certainly going too hard and will pay for it later. Ease off until it settles. In the second half, heart rate matters less; this is where you rely on effort and pace. The guide to HYROX pacing strategy puts this into a full race plan.
Wrist or chest strap?
Wrist-based optical sensors are convenient and reasonably good for steady running, but they struggle during HYROX-style work. Gripping a sled rope, SkiErg handles or kettlebells, and the rapid arm movements of wall balls, all interfere with the reading. A chest strap is generally more reliable for intervals and stations.
Whichever you use, check that the numbers make sense. If your watch says your heart rate is 110 during a hard wall ball set, it is wrong, and you should trust how you feel.
Wear the strap snugly just below the chest muscles, dampen the sensor before you start and replace the battery before race week. A strap that drops out halfway through a race is worse than no strap at all.
Heart rate for recovery
Resting heart rate and heart rate variability can hint at how well you are recovering. A resting heart rate noticeably higher than normal for several mornings, or a sustained drop in heart rate variability, can mean you need an easier day. The guide to heart rate variability explains how to use these without obsessing.
Structured conditioning is where heart rate training comes into its own. Lycan Strength runs Engine classes on Monday and Wednesday evenings and Friday mornings, plus Lycan Shred on Friday evenings, all listed on the timetable. The guide to building your engine for HYROX explains how those sessions fit together.
Members' guide
Keep reading with your free week
The full guide is for members and people on a free trial. Claim 7 days free and it opens straight away on this device, along with every other guide.
Already a member? Log in to read it
Unlock the full guide
Seven days of classes, free. We will be in touch to book your first session.
Questions
What heart rate zone should I train in for HYROX?
Most of your training should be easy, comfortably below threshold, with one or two sessions a week at or above threshold.
How do I find my threshold heart rate?
A common field test is a 30-minute all-out but evenly paced effort. Your average heart rate over the final 20 minutes is a good estimate.
Should I race HYROX by heart rate?
Use it as a ceiling in the first half to stop you starting too fast. In the second half, rely more on effort and pace.
General guidance for healthy adults. If you have a medical condition, injury or are pregnant, check with a health professional before changing your training or diet.