Ramp tests and interpreting the results.

We are currently in that time of year when you might have taken a brief break from cycling and training in general, and now you're ready to get back into the routine.

Many athletes begin by performing a test to determine their current fitness baseline and to identify key training zones, especially their threshold power and heart rates.

A straightforward and repeatable test is the ramp test. It's also easy to pace, unlike a 20-minute test, which requires more skill to perform effectively.

Beyond just obtaining an approximate FTP / Anaerobic threshold you can also glean a bit more info from looking at the data, in particular the heart rate profile.

Below are 3 different ramp tests from different athletes.

I’ve tried to indicate two key points on each of the tests which show inflection points, these are often good indicators of your physiological markers.

The two primary physiological inflection points are:

First Ventilatory/Lactate Threshold (VT1 or LT1) – Often this marks the transition from moderate intensity to heavy.

At this point the blood lactate concentration will begin to rise above resting levels. This should also correspond to the top of your Z2.

Second Ventilatory / Lactate Threshold  (VT2 / LT2) – This marks the transition from heavy to severe intensity.

This is the point where lactate accumulation exceeds the bodies ability to clear it, also referred to anaerobic threshold or OBLA (onset of blood lactate accumulation). Exercise at this intensity can only be sustained from a limited period of time, up to around one hour in highly trained individuals.

Athlete A

Ramp test result with markers for inflection points

Athlete B

Ramp test result with markers for inflection points

Athlete C

Ramp test result with markers for inflection points

The Big Picture: Efficiency and Fitness

At its core, the HR-to-Power relationship is a measure of cardiovascular efficiency. A more efficient athlete will produce more power for a given heart rate. The trends you see illustrate how well your body is delivering oxygen to your muscles and how effectively those muscles are using it.

Key Insights from the HR/Power Trend

1. The Shape of the Curve: Linear vs. Curvilinear

Ideal Scenario: A Linear Relationship (at first)

What it looks like: For the first several minutes of the test, your heart rate increases in a straight, predictable line with the increasing power.

What it means: This indicates good cardiovascular efficiency and a well-conditioned aerobic system. Your body is comfortably meeting the energy demands by increasing cardiac output and oxygen utilization.

The Inflection Point: The HR "Turn" or "Decoupling"

What it looks like: As you approach your maximum effort, the HR line will start to "bend" upwards. It's no longer a straight line; it takes a sharper, steeper curve. This is the Heart Rate Inflection Point. In reality it can also appear as a sudden jump as the body responds to the increasing demand – this is evident in the three examples above.

What it means: This is the point where your body can no longer meet the energy demand aerobically and has to rely increasingly on anaerobic metabolism. It's a sign of extreme physiological strain and is a very strong indicator of your functional performance limit. The power at which this occurs is often very close to your FTP or Lactate Threshold (LT2).

2. The Slope of the Line: Aerobic Efficiency

A Flatter Slope (Lower HR for a given power)

What it means: This is a sign of high efficiency and superior aerobic fitness. Your heart doesn't have to work as hard to produce the same power. This is the goal of endurance training. You might see this improve over a season of training.

A Steeper Slope (Higher HR for a given power)

What it means: This indicates reduced efficiency. This can be caused by several factors: Fatigue/Overtraining: Your body is stressed, and your cardiovascular system is working harder to do the same work.

Lack of Fitness: Your aerobic engine simply isn't as developed.

Dehydration or Heat Stress: Both force your heart to work harder to cool the body and maintain cardiac output. Illness: Even a minor bug can significantly elevate your HR.

3. Heart Rate Lag and "HR Drift"

The Lag: At the very start of the test, power will increase immediately, but your heart rate will take 30-60 seconds to "catch up." This is normal.

HR Drift (Cardiovascular Drift): In longer ramp tests or if you are dehydrated, you might see your HR continue to creep up even when the power is held constant on a step. This is a sign of cardiovascular strain and thermoregulatory load.

4. Maximum Heart Rate (HRmax)

The test will give you a good, effort-based estimate of your current HRmax. This is valuable for setting accurate training zones. Compare it to previous tests—a significant drop in achieved HRmax could be a major red flag for overtraining or fatigue.

Practical Application: Putting It All Together

Lets compare the three tests pictured above.

The first thing, if you look closely you can make out key inflection points, which give approximate indications where those key physiological markers likely sit.

For Athlete A – the first inflection point is less obvious than athletes B and C, however you can see a small plateau before rising

Athletes B and C have a more pronounced change in heart rate, you’ll note that I have placed the arrows prior to the inflection as it’s this point, before the HR changes which represents the theoretical VT1/LT1 and VT2/LT2. The reason being is that heart rate is a lagging indicator.

If we then look at the distance between the two inflection points, you can also get a sense of the phenotype for each athlete.

Athletes A and C have a slightly shorter gap between the two points, however they continue for longer beyond the second inflection point. This points to these two athletes having a slightly higher anaerobic capacity compared to athlete B.

Athlete B is likely more of an aerobic athlete and possibly lacks the same anaerobic contribution.

So if you are interpreting your own ramp test results it’s worth trying to understand what your phenotype is, a high anaerobic capacity could result in a high final 1 minute power but could end up overstating your FTP estimate. Similarly of you are a time triallist then you might lack that top end punch and therefore taking the standard 75% might understate your FTP.

This is why having a mix of data points is useful so you then have more context in which to interpret the ramp test result.

Limitations and Caveats

HR is Influenced by Many Factors: Caffeine, stress, sleep, and temperature all affect heart rate. Don't over-interpret a single data point.

It's Not a Direct Measure of Lactate: While the inflection point correlates well with lactate threshold, it is not a direct measurement. For true precision, a blood lactate test is needed.

Compare Like-with-Like: Always compare tests done under similar conditions (time of day, nutrition, equipment) for the trends to be meaningful.

Also dual record if you can, I’ve seen so many really bad power meters, particularly Wattbikes and some home trainers.

Summary: What to Look For

Observation	What It Likely Means
Flatter HR/Power slope	Improved aerobic fitness & efficiency
Steeper HR/Power slope	Fatigue, dehydration, or lack of fitness
Higher Initial HR	Fatigue, stress, or insufficient warm-up
Clear, late Inflection Point	Well-defined threshold & good test execution
Low or Unachieved HRmax	Overtraining or incomplete test effort
HR consistently lower for same power	Positive adaptation from training

By analysing both the power number and the heart rate story behind it, you transform a simple fitness test into a powerful diagnostic tool for guiding your training.

I go into some detail in my YouTube video so check it out - https://youtu.be/KajPDGTMA_8?si=gNheF3pEalioVLWP