General Discussion Triathlon Talk » LT HR compared to Aerobic threshold HR Rss Feed  
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2009-04-09 6:18 AM


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Subject: LT HR compared to Aerobic threshold HR
Just a random question, but how do these two thresholds vary? Do they share a  similar HR? I ask as  I did a vo2 test and had a Aerobic threshold HR of 176, and field tests have shown my LTHR at 177.

Thanks


2009-04-09 7:31 AM
in reply to: #2073040

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Champion
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Subject: RE: LT HR compared to Aerobic threshold HR
In my (non-professional) experience, you'll see different definitions of these terms in different places.  For example, some will say that LT is the point at which lactic acid concnetration in the blood begins to increase.  Others say that LT is the point at which it becomes 4 mmoL/l.  Still others call the latter OBLA.  And others instead call the latter anaerobic threshold.  The term 'ventilatory threshold' also gets thrown around in this context -- one by-product of lactic acid 'clearing' is CO2, which is expelled by breathing, so when CO2 production goes up, respiration increases, and I've seen 'ventilatory threshhold' used to describe the point at which this occurs.

I've read things that suggest that there is an order to these events:  first LT occurs (lactic acid concentratin begins to increase); then you hit AT (4 mmoL/l), at which point, supposedly, anaerobic energy streams -- especially anaerobic glycosis -- become important; then you hit VT (to expel the CO2 that results from converting lactic acid to lactate, which is then used as energy, causing the release of CO2).

I don't think there is any significant practical upshot.  From what I've read, even if you care to make these distinctions, the differences in HR are less than the error involved in measuring them.

Edited by Experior 2009-04-09 7:33 AM
2009-04-09 8:09 AM
in reply to: #2073040

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Subject: RE: LT HR compared to Aerobic threshold HR
Bani - 2009-04-09 6:18 AM Just a random question, but how do these two thresholds vary? Do they share a  similar HR? I ask as  I did a vo2 test and had a Aerobic threshold HR of 176, and field tests have shown my LTHR at 177.

Thanks
VO2 max is the maximum volume of oxygen that your  body can consume during intense exercise. This volume is expressed as a rate of either: liters per minute (L/min) or millilitres per kilogram of  body weight per minute (ml/kg/min). Since oxygen consumption is related to energy expenditure thus when we measure oxygen consumption, we are also measuring an individual's maximal capacity to do work aerobically. Lactate Threshold OTOH is scientifically defined as the increase of 1 mmol/liter over the athletes's exercise baseline (rest), however what we usually refer to LT on tri  and endurance training is related to Maximum Lactate Steady State which is defined as the highest steady state exercise intensity one can maintain while keeping balance between the elimination of blood lactate and difussion of lactate into the blood.

These two intensity levels usually happen at different rates hence your HR at VO2 max in general will be higher than your LT. The point of training is to increase your VO2 max and LT and bring the latter as close to the former as possible. Highly trained individuals usually show values closer to each other while untrained ones the differences are more significant; in your case my guess is that your VO2 max and LTHR are different. How did you test VO2max and LTHR?
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General Discussion Triathlon Talk » LT HR compared to Aerobic threshold HR Rss Feed