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You can also do a step protocol similar to a Conconi test. The only difference is that instead of looking for the HR deflection, which is meaningless, you carefully monitor your breathing in order to detect the ventilatory threshold (VT). The VT is NOT the AeT and it correlates very well with the usual measurements for "lactate threshold" (LT, AT, MLSS, etc). With this test you can find a decent approximation of your threshold HR and check for improvement in the speed at which you reach VT, even though this speed is not your steady-state VT speed.