Tempo run complications

There are 30+ definitions of "lactate threshold".

Stop this ex phys bs. Get a coach that focuses on paces not bogus science.

Because your body doesn't know goal pace. It knows effort. Do your tempo runs by effort and you will make progress.

mrtalent wrote:

my heart rate never goes above 165 during my tempo run, staying around 160. Why is my heart rate so low even though I get tired and cant hit my goal pace?

Your maximum heart rate varies according to the amount of plasma in your blood. More plasma = lower heart rate at rest and during exercise. So using your highest recorded heart rate is completely unreliable as a guide.

And your pace will vary for many reasons. You are likely to be slower on a warm day in summer than a cool day in spring.

There are thousands of tempo run threads telling you to run by feel and not some imaginary target pace. Follow that advice.

OP, I have the same issue. I can never seem to hit my target tempo pace - usually off by 10-15sec/mile. My legs just get tired. Tempo runs often turn into marathon pace runs for me. I'd like to tell myself to run by effort and feel, but usually end up trying to hit the prescribed pace.

Stop using your watch. I don't wear one. It really helps you get a better feel for running. I know this is too weird for all you ocd runners, but what is your main priority, learning how to run faster naturally or obsessing over silly numbers?

Everyone giving the "run by feel, not by pace" advice is giving you good advice. Pace will vary with heat, wind, rain, running surface, topography, recent workouts, changes in running volume, natural body rhythms, hangovers, eating habits and more.

That being said, I still find myself using pace as my primary guide, using experience to make small adjustments based on the above factors. But just because I arguably do it more wrong than right doesn't mean you shouldn't heed the advice of the other posters, particularly if you are relatively inexperienced.