Pace Calculator

Training with Pace and Heart Rate

When it comes to endurance training, two key metrics often come into play: pace and heart rate. Pace refers to the speed or rate at which someone is moving, usually measured in minutes per mile or kilometer. Heart rate, on the other hand, is the number of times your heart beats per minute (bpm). These two are closely linked—generally, as your pace increases, so does your heart rate.

Using both pace and heart rate together in your training can help monitor your fitness level, avoid overtraining, and track your progress more effectively over time.

How to Measure and Estimate Heart Rate Zones

You can measure heart rate in a few different ways—either by using a heart rate monitor or manually checking your pulse at the wrist or neck. Key heart rate values to understand include:

• Resting Heart Rate (RHR): This is your heart rate when you’re relaxed and at rest. A normal range for adults is often considered to be 60–100 bpm, though some health professionals argue a better range is 50–90 bpm. Generally, a lower RHR suggests better cardiovascular fitness, but extremely low or high values may indicate a health issue.

• Maximum Heart Rate (MHR): This is the highest heart rate your body can achieve during intense exercise. The most commonly used formula to estimate it is:
  MHR = 220 – your age

While this formula offers a simple estimate, it doesn’t account for individual differences or provide a margin of error. The most accurate way to determine MHR is through a clinical stress test. However, this formula is often used to set heart rate zones for training, such as:

• 60–70% of MHR: optimal for fat burning

• 70–80% of MHR: aerobic training zone

• 80–90% of MHR: anaerobic zone

Aerobic vs. Anaerobic Training

Aerobic Exercise

Aerobic activity is performed at moderate intensity over a longer duration—such as jogging or cycling—and uses oxygen to fuel your muscles. Typically done at 70–80% of your MHR, this type of training helps improve cardiovascular endurance and burn fat efficiently. A heart rate intensity of 55–85% of MHR for 20–30 minutes is commonly recommended for optimal results.

Anaerobic Exercise

Anaerobic exercise involves high-intensity efforts, like sprints or heavy lifting, done in short bursts. At around 80–90% of your MHR, your body shifts to using glycogen for energy, leading to a build-up of lactic acid in your muscles. This buildup causes the “burning” sensation and can limit how long the activity is sustained.

Although some lactic acid is produced during aerobic activity, it is cleared quickly from the bloodstream. In anaerobic workouts, however, excess lactic acid can accumulate, causing fatigue unless properly managed with rest.

Understanding Threshold Paces in Training

When training for endurance events like marathons, identifying your aerobic threshold pace is essential. This is the fastest pace you can maintain while still primarily using oxygen (aerobic energy). Improving this threshold allows you to run faster over long distances without fatigue.

The anaerobic threshold pace, sometimes called the lactate threshold, is when the body begins to rely more on stored glycogen for energy, leading to quicker fatigue. While this pace is not ideal for long-distance runs, training near or slightly above it can boost overall fitness and speed.

How to Estimate Your Thresholds

Lab testing is the most accurate method for determining aerobic and anaerobic thresholds, but practical alternatives exist:

• 30-Minute Time Trial Method:
  Run for 30 minutes at maximum effort. Track your heart rate throughout and calculate the average heart rate from the final 20 minutes. This is a good estimate of your lactate threshold heart rate (LTHR).

  • If training with others, extend the run to 60 minutes for a more accurate result.

  • To estimate your aerobic threshold heart rate, subtract 30 bpm from your LTHR.

By training near your threshold, you can delay the point at which fatigue sets in, helping you perform better over longer distances.