Question: I make adjustments to threshold pace for the duration of a tempo run. How should I adjust threshold pace at altitude? I coach runners at 5,200 feet.
Run SMART Coach Jack Daniels: If using sea level race performances and associated VDOT values (or typical sea-level training speeds) while at altitude, you must adjust the paces. At 5000 feet of altitude, the adjustment for Interval and Threshold runs would be about 8-10 seconds PER MILE (about 2-3 sec per 400) SLOWER than the sea-level paces. No adjustment needed in Rep paces as the duration of rep runs are short enough to not need to adjust, but you may need a little longer recoveries between bouts of work in a Rep session. No adjustment needed in the recoveries in Interval or Threshold work bouts because you are adjusting the training paces.
At 7000 feet of altitude the adjustment is more like 15-18 seconds per mile slower than sea level. To simplify, figure about 1+ seconds per 400 meters (4-5 sec/mile) per 1000 feet above 3000 feet of altitude, at 4000 alt = 4-5 sec/mile, 5000 alt = 8-10 sec/mile, 6000 alt = 12-15 sec/mile, 7000 alt = 16-20 sec/mile, 8000 alt = 20-25 sec/mile, etc.
To calculate your training and race paces at altitude, use Jack’s calculator.
Quick note for anyone who is confused about the technical jargon:
Threshold training is made up of steady, prolonged runs called tempo runs or intermittent runs with brief recoveries called cruise intervals, both of which are run at the same intensity. The purpose of threshold training is to increase endurance. To give you a quick reference in terms of how hard the effort should be on a threshold training run, it’s roughly 88-92% of your heart rate max.
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