Recording-2025-03-24T15:49:51.332Z

Heart Rate Reserve (HRR) and Exercise Intensity

• Definition and Importance

  • Heart Rate Reserve (HRR) is calculated using the difference between maximal heart rate and resting heart rate. It's crucial for understanding relative intensity in exercise programming.

  • Heart rate acts as the body's speedometer for cardiovascular effort, reflecting how hard one is working.

  • It is auto-regulatory, influenced by various factors such as dehydration and sleep deprivation.

• Influencing Factors on Heart Rate

  • Dehydration increases heart rate due to lower stroke volume.

  • Sleep deprivation leads to an elevated heart rate.

  • Stimulants (e.g., caffeine or drugs) also increase heart rate levels.

• Heart Rate Reserve vs. Percentage of Max Heart Rate

  • HRR considers resting heart rate, making it more accurate compared to merely using the percentage of maximum heart rate, which doesn’t account for individual variations in resting heart rates.

  • %HRR provides individualized intensity measures that better correspond to physiological responses than %MHR.

Relative Intensity and RPE (Rate of Perceived Exertion)

• Explaining Exercise Intensity

  • Relative intensities are expressed through both HRR percentages and Rating of Perceived Exertion (RPE).

  • A practical method for athletes is to equate RPE to HRR percentages, e.g.,

    • 60% HRR ≈ RPE of 6

    • 70% HRR ≈ RPE of 7

    • 80% HRR ≈ RPE of 8

• Application in Programming

  • Prescribing exercise intensity via RPE offers a more relatable measurement for people unfamiliar with specific heart rate values.

  • Absolute measures (like speed, grade, or METs) need to be determined through calculated or observed data to ensure effective programming.

Lactate Threshold (LT) in Graphed Training

• Understanding Lactate Threshold

  • The lactate threshold is important for determining exercise intensity and is measured by a point where lactate accumulates rapidly in the blood.

  • LT is affected by muscle oxygen levels and the reliance on glycolysis versus aerobic metabolism. Key points:

    • Low muscle oxygen leads to increased glycolysis, resulting in a buildup of pyruvate that ultimately forms lactate.

    • The accumulation of lactate is associated with a drop in pH, leading to a more acidic environment (acidosis) and resulting in fatigue.

• Training Implications

  • Well-trained athletes can perform at a higher percentage of their VO2 max before reaching LT; for example, elite distance runners may sustain efforts much closer to bodily limits for longer periods.

  • Training can shift an individual's lactate threshold to a higher intensity, thereby enhancing performance, especially in endurance events.

• Components Influencing Lactate Threshold

  • Both genetics and training impact lactate threshold.

  • Increases in mitochondrial density and capillary networks can lead to better lactate buffering, thereby improving athletic performance.

Types of Training Relative to Lactate Threshold

• Types of Training Approaches

  • Various training methodologies are structured around lactate threshold, notably:

    1. Endurance Training - Targets aerobically relevant thresholds.

    2. Tempo Training - Maintains exercise above the aerobic threshold but below maximal lactate steady state.

    3. Lactate Threshold Training - Engages the body just above lactate threshold to improve tolerance and clearance.

    4. VO2 Max Training - Utilizes efforts beyond the maximal lactate steady state to improve maximum aerobic capacity.

• Training in Different Intensities

  • Effective exercise prescription involves knowing where a client or athlete is relative to their lactate threshold and establishing a suitable training strategy that targets specific performance goals without exceeding tolerable exertion levels.

Practical Implications of HRR and Lactate Threshold

• Client Examples and Measurements

  • Individual exercise programs based on HRR consider varying resting heart rates and maximum heart rates; calculations are needed to achieve precise target heart rates.

  • Calculations for HRR become essential for tailoring fitness programs for clients, ensuring appropriate intensity levels are prescribed.

  • Example Calculation: For a theoretical 25-year-old with resting heart rate 70 and wanting to exercise at 65% HRR:

    1. Max HR = 220 - Age = 220 - 25 = 195 bpm

    2. HRR = Max HR - Resting HR = 195 - 70 = 125 bpm

    3. Target HR = (HRR × % intensity) + Resting HR = (125 × 0.65) + 70 = 151.25 bpm

• Applications in Special Populations

  • Programming guidelines must take into account individual capabilities, especially in unique populations (e.g., cardiac patients) by monitoring intensity effectively through HR measurements and lactate levels.