For this reason, LTHR testing is preferred.
Before performing the test, it’s important to buy a good heart-rate strap.

Chest and arm straps from brands such as Garmin, Wahoo, Polar, Coros and CooSpo are much more accurate and responsive than the wrist-based sensors in smartwatches.
HOW TO PERFORM A LACTATE THRESHOLD HEART-RATE TEST
The most widely used test for LTHR was developed by elite endurance sports coach and author Joe Friel. British Cycling endorses this test, and they offer a useful zone calculator, into which you can put your LTHR test result.
The test is a 30-minute, all-out effort. The aim is to go as hard as you can for 30 minutes at a steady output without fading significantly at the end.
A common mistake when performing this test is starting too hard, so start conservatively, and as Joe Friel recommends, evaluate your effort every five minutes to see if you can go harder in the following five-minute block. Correct pacing is required to get an accurate result.
Your LTHR is your average heart rate for the last 20 minutes of the 30-minute effort. This information can be obtained through training software or apps like Garmin Connect or Wahoo Fitness. Alternatively, you can use the Lap function on your head unit, smartwatch or indoor-training platform after 10 minutes. This separates the analytics of the last 20 minutes from the first 10.
The FTHR test is best performed on a long, flat road without traffic lights; a long, steady climb; or on an indoor trainer. If you don’t get the pace right the first time you perform this test, repeat it again a few days later to get a more accurate result. Also, you’ll get the most accurate number by doing it when you’re well rested.
ARE CYCLING HEART-RATE ZONES BY AGE ACCURATE?
The formula Max Heart Rate = 220-Age is commonly understood to be a quick way to estimate MHR. However, the margin of error (10-12bpm) is so large that the formula is almost useless, as the authors of this study conclude.
Testing your max heart rate and using that number to calculate training zones is less accurate than using your lactate threshold heart rate, so using an arbitrary formula to calculate your max heart rate and set your training zones is a waste of time.

HEART RATE VS. POWER: WHICH IS BETTER FOR CYCLING TRAINING AND WHY SHOULD CYCLISTS TRAIN BY HEART RATE?
Your heart rate is an indicator of your body’s response to physical exertion, which is why it’s a good metric for structuring cycling workouts.
Training with power-based zones is regarded as the gold standard for accuracy, but a power meter is much more expensive than a heart-rate monitor (HRM). In general, heart-rate training is accurate enough for non-competitive cyclists to make consistent performance gains, and all that is required to train by heart rate is a good HRM and a way to see it while training, such as on your indoor trainer, smartwatch or bike computer.
With this equipment, you can perform a max heart rate or lactate threshold heart-rate test and plug your result into a training zone calculator to get your personalized zones. This information can then be used to follow your preferred cycling training plan.
There are various ways to test your threshold power in order to set power-based zones. Training with power is more accurate than training with heart rate, as fewer external factors influence the numbers once the device is calibrated before each ride. You can also use power to measure maximal efforts, which isn’t possible with heart rate.
LIMITATIONS OF USING HEART-RATE TRAINING FOR CYCLING
It’s worth noting that using heart rate as a training metric has its limitations. Firstly, your heart rate is affected by multiple external factors.
For example, if you’ve slept poorly or are feeling physically tired or mentally stressed, you may have a higher average heart rate. In contrast, if you’ve had several days of poor sleep or done multiple hard days of training, your max heart rate and average heart rate may be lower.
Temperature also plays a big role in heart rate. On hot days, you will certainly have a higher average heart rate than on cold days. Dehydration or inadequate fueling can also raise your heart rate.
Another important consideration is cardiac drift. This is the gradual increase of heart rate during a long workout, even while maintaining the same effort.
Lastly, heart rate doesn’t increase or decrease quickly enough to be used as a metric for short efforts. For example, if you do a short 10-second max-effort sprint and stop riding straight away, your heart rate will not reach its maximum. In this example, it will likely take several seconds to reach a certain point, then start decreasing again, and even longer to return to baseline. Therefore, in the absence of a power meter, short efforts of below three minutes, such as in interval-style workouts, should be carried out using perceived exertion. In Dr. Coggan’s table, Zones 6 and 7 are as follows:
- Zone 6 (30 seconds to 3 minutes) >7 out of 10 perceived exertion
- Zone 7 (<30 seconds): Maximal perceived exertion
WHAT HAPPENS IF YOU HIT YOUR MAX HEART RATE WHILE CYCLING?
Reaching your max heart rate in cycling is very uncomfortable and typically occurs only after you’ve sustained near-max effort for several minutes, ending with a sprint until failure.
In a healthy individual with no underlying cardiac risk factors, hitting max heart rate, or close to it, is perfectly safe, and it’s necessary for cyclists who wish to compete, as many races finish with these sorts of efforts.
Before adding vigorous-intensity exercise to your routine, be sure to speak with your doctor, who may suggest certain tests first. That said, underlying issues can also be triggered by less-intense efforts, so understanding your cardiac risk is generally good practice.
When exercising, if you notice anything unusual, such as a heart rate that’s much higher than normal for a given output, stop what you’re doing and schedule an appointment with your doctor. Likewise, if you experience chest pain, dizziness, lightheadedness, an irregular heartbeat, unusual shortness of breath, or nausea, seek medical advice.
HOW TO USE HEART RATE-ZONES IN REAL CYCLING WORKOUTS
Once you’ve tested your LTHR or MHR, you can use that information to create or follow a training plan that matches your goal, be it a mountainous sportive or a local crit race.
All general training plans will include a mix of sessions of varied lengths with efforts of different intensities and dedicated recovery between efforts and training sessions.
If your goal is overall fitness, you can follow a general plan, but if, for example, your goal is a multiday long-distance ride, you may prioritize longer Zone 2 and 3 efforts over short high-intensity interval sessions, as these intense efforts will increase the time needed to recover and potentially reduce your ability to do goal-specific training.

Let’s say you have seven hours available for your cycling training each week, you could break that into four sessions as follows:
Monday: 30min - 7min Zone 2 (warm-up), 18min 3x3min Zone 5/Zone 1 intervals, 5min Zone 1 (cool-down)
Wednesday: 2 hours - 2x20min Zone 4 + Zones 1-2
Friday: 1.5 hours - 2x30min Zone 3, 30min Zone 1
Saturday: 3 hours - Steady ride Zone 2-3
In the example above, there’s a full day of rest after the two higher-intensity sessions.