Heart Rate Based Training & Physiological Testing Demystifying the metabolic side of performance Dr. Paul Weiss Chief Program Officer Asphalt Green

Heart Rate Based Training Tonight’s workshop is going to primarily address these three questions: Why is heart rate used as a metric for gauging intensity and for designing a training plan? What physiological markers are represented by the intensity “zones” that describe heart rate based training? How does physiological testing work, and what technology is most important for performance enhancement?

What does your HR actually indicate? HR responds (primarily) to your demand for oxygen As frequency and intensity of muscle contractions increases, fuel consumption quickens, which increases the demand for oxygen As your HR increases, the source of energy for muscle contractions shifts from Fat to Carbohydrate Lipid Metabolism is more efficient/Glycolysis is more immediate Your heart rate and respiration rate will increase to meet the increased sugar/oxygen demand, until physiological limits are met Some of these limits are very trainable (lactate tolerance, capillary bed development), some less so (Anaerobic Threshold or ‘AT’ & VO2 Max)

Religion, Politics and HR Zones 1 2 3 4 5 Range 118 151 152 170 171 177 178 185 186 197 ** % AT 66% 85% 96% 100 100% 107% 111%   Recovery Aerobic Sub-AT AT AT - Power

Zones = Physiological Markers At effort levels below 85% of your AT, you burn more fat than carbohydrate for energy, and your demand for oxygen is low Aerobic threshold, achieved at roughly 85% of AT, is defined by an erosion of lipid metabolism and an increase in glycogen consumption. Aerobic threshold is the “tipping point” when your demand for energy at the cellular level can’t be met by lipids. The aerobic, or “base” training range starts at the aerobic threshold, extends to the point where you are utilizing about 2x as much sugar as fat for energy, which is at roughly 95% of AT

Anaerobic Threshold & Blood Lactate AT is horribly misunderstood (often confused with VO2, which is a very different metric) Metabolically, it is a very simple marker: AT is the tipping point at which you can no longer bring enough oxygen to working muscles to efficiently operate the Krebs Cycle. As a result, waste is produced; the key waste product is Lactic Acid (which isn’t always a bad thing)

What is VO2 max? The maximum amount of oxygen that an individual can utilize in a set period of time (generally expressed as a volume, i.e. liters per min), normalized per kilogram of body weight (i.e. ml per kg BW per min). It is a measurement of the upper limit of an athlete’s oxygen carrying capacity, which includes lung-volume, heart-stroke volume, alveoli development, arterial plasticity, and capillary bed development. Think of VO2 max as a measure of the “size of an athlete’s cardiovascular engine"

Lactic Acid, Buffering, and Toughness Lactic Acid is a waste by-product of metabolizing sugar at the cellular level in a low-oxygen (anoxic) environment Lactic Acid is a fuel source, and can be used at the cellular level for energy (drawn into mitochondria as fuel, replacing ATP) Using a variety of systems, including a modification of lipid metabolism, you can train your muscles to buffer, or neutralize the PH change, caused by lactic acid overproduction The combination of pain tolerance and buffering capacity is the main differentiator between elite and sub-elite endurance athletes…and this is a very trainable ability, but it hurts. A lot.

Improving lactate buffering capacity This capacity is developed in three ways: increasing your capacity to effectively and efficiently stay in high Zone 3 and Zone 4 (building aerobic base and vascularity): TT’s challenging your system with short, explosive 20-30 second ALL OUT efforts in Zone 5 generally training ABOVE race pace in the grey area between Zones 4 and 5 (1-4 minute intervals, often while climbing) Legendary swimming coach Doc Counsilman developed a 5 Zone model, based on research with world class swimmers, referring to the zones as Easy/Moderate/Hurt/Pain/Agony; unfortunately, he’s right, this is how the zones feel

VO2 Max/AT Testing & Blood Lactate A common misconception is that Anaerobic Threshold (AT) and Lactate Threshold (LT) are different Physiological markers. They are the same metabolic shift, measured different ways AT is a leading indicator, LT is a trailing indicator Measuring LT is most appropriate for athletes whose VO2 at AT is 95% of MAX VO2 or higher. Those athletes are elite. Elite athletes, who are very well trained, will have moved their AT nearly as close to MAX VO2 as possible, and improvements in wattage production and velocity will happen at an intensity level above AT, so lactic acid buffering capacity is their most important area of focus

Velocity, Wattage and Speed The most important relationship between heart-rate and training/race performance is velocity or energy production at your target HR. Understanding the concept of “decoupling” Wattage: measure of power (work done during a specified unit of time). 1 watt = 0.73756 ft-lbs/sec, 0.01433 Calories/min, 0.0013 horsepower, or 6.12 kg-meter/minute Using wattage production on a bike as a leading indicator, in combination with HR can be very useful, particularly for the more advanced athlete (see “decoupling” above)

Field Testing for Anaerobic Threshold There are several standard field-testing protocols for establishing AT in run and bike using average HR for a best-effort TT for 20 or 30 minutes What does a field test actually measure? An “adjusted” AT! AT is one of several variables that contribute to a field test result, so the best practices application of a field test is to measure the affects of variables other than AT, which means it is both more AND less accurate Cycling: average HR during a 30 minute effort. Sometimes shorter (20 minutes) for recreational athletes. Can be simulated on a computrainer to insure a non-variable stimulus (flat road) Running: average HR during a 20 minute effort. For elite athletes a 10k distance is often used. For recreational athletes a 5k distance is often used. Can be done on a flat outdoor surface or treadmill.

Testing Technology and Results The Korr Cardio Coach medical-grade gas-exchange analysis unit measures the ratio of exhaled O2 vs CO2, volume of respiration, respiration rate, and changes in PH As more blood sugar is consumed, lipid metabolism is reduced, and AT is approached, the ratio of exhaled CO2 to O2 will shift until AT is achieved, at which point nearly all exhaled gas will be in the form of CO2 The results of a VO2Max test include AT, VO2 Max, VO2 Max @ AT, and rate of recovery. From these numbers HR zones can be calculated very accurately, and % of VO2 @ AT

Summary and Q & A Training: most endurance athletes should do the vast majority of their training in Zone 2 (80%+) Athletes who are VERY well conditioned, with an efficiency level above 95%, will get more benefit from high intensity (Z4+) training than less conditioned athletes Most endurance athletes fall into the same trap: their long easy work is neither long enough, nor easy enough. Their short/high-intensity work is neither short enough, nor hard enough. Training with wattage on the bike can be very helpful, but it’s only truly useful in the context of the heart rate zones associated with wattage production