The primary goal for endurance athletes is to be able to exercise at low to moderate intensities for hours at a time. Endurance training requires that the majority of the training be done in the Endurance Zone (below the aerobic threshold (AeT). At this intensity, fat metabolism provides more than half of the energy needed for movement. The body metabolizes fat stores for an almost unlimited supply of energy and processes lactate faster than it is produced. The lower intensity training also reduces the stress to the musculoskeletal system so that you can train more often. Another important aspect of Endurance Zone training is that it raises the aerobic threshold over time. This allows training at higher intensities for longer times while still using fat as a primary energy source and processing lactate faster than it is produced.
Keeping Intensity In Check With A Heart Rate Monitor
I highly recommend beginning athletes train with a chest strap heart rate monitor to keep Endurance Zone workouts below the aerobic threshold (it is very easy to drift above the AeT into the Threshold Zone without a monitor!). The Wahoo Tickr with the Wahoo fitness app is the one I use. One of the best features is the ability to download your workout directly to Training Peaks with a single push of the button on the app. To get your target heart rates for Endurance Zone, the MAF 180-age formula is a good way to conservatively estimate the upper end of the Endurance Zone. More information on this: Estimating Aerobic Threshold MAF 180 Formula.
Stay In The Zone With The Talk Test
When training in the Endurance Zone, you should be able to speak comfortably. The ability to speak in full sentences, recite the alphabet, speak for 10 seconds is considered comfortable. This is often referred to as “conversational pace”. As long as you can speak comfortably, you are almost definitely below the aerobic threshold. As you approach the upper end of the Endurance Zone and the aerobic threshold, talking in complete sentences becomes more challenging.
Assessing Endurance Zone With Nose Breathing
A good way to quickly assess that you are training below your aerobic threshold in the backcountry is the ability to breathe through your nose. If you are below the aerobic threshold, you should be able to easily breathe through your nose. As intensity approaches the upper end of the Endurance Zone and the aerobic threshold, nose breathing becomes deep and steady.
Endurance Zone training should make up the majority of your training volume (80+% of training time) if your goal is any activity lasting multiple hours. Next weeks article will discuss the Aerobic Threshold in detail. If you have any questions, please send me an email at email@example.com.
Ventilatory threshold is a great tool for estimating training intensity in the field. The Talk Test was first used by Professor John Grayson of Oxford University in 1939. The talk test was used to advise English mountaineers to “climb no faster than you can talk”. In more recent times, it is referred to as “conversation pace”. Recent research has found a close correlation exists between the ability speak and training intensity.
Below Ventilatory Threshold 1 (<VT1)
Below VT1, the majority of energy production comes from fat and lactate is easily metabolized. The ability to speak comfortably and carry on a conversation is a good way to assess if you are below VT1/aerobic threshold in training and in the mountains. The ability to speak in full sentences, recite the alphabet or speak for 10 seconds is considered comfortable. As you approach the aerobic threshold/VT1, talking in complete sentences will become more challenging.
Ventilatory Threshold 1 (VT1)
Ventilatory Threshold 1 is the point at which ventilation starts to increase in a non-linear fashion. It is the point of transition where the body is using more carbohydrates than fat for energy production. It is also the point at which lactate is produced faster than it can be cleared by the body. At Ventilatory Threshold 1, continuous talking is no longer comfortable. Conversation will become limited to a few words at a time to short sentences. Training at VT1 is approximately the highest intensity that can be sustained for one to two hours of exercise in well trained athletes.
Ventilatory Threshold 2 (VT2)
VT2 is a close approximation to OBLA (onset of blood lactate accumulation). OBLA is the point that blood lactate accumulates faster than the body can metabolize it. Talking at VT2 will be limited to a few words. Training at VT2 is approximately the highest intensity that can be sustained for 30-60 minutes in well trained individuals.
Above Ventilatory Threshold 2 (>VT2)
Exercise above VT2 is very high intensity training. Above VT2, talking is almost impossible. Exercise above VT2 can be sustained for 30 seconds to a few minutes (in elite athletes) due to an accumulation of blood lactate. The higher the intensity you train at above VT2, the shorter the amount of time you can sustain that intensity.
Ventilatory thresholds are a powerful tool for endurance athletes to quickly assess training intensity in the field. Knowing if your pace is sustainable for seconds, minutes or hours is crucial to success on an all day or multi-day endurance effort in the mountains.