At some point during the past decade, fitness publications began gushing over workouts that emphasized short, hard effort reps, aka high-intensity interval training (HIIT). As the broader public appeared to be discovering the benefits of HIIT, dedicated endurance athletes had an excuse to feel even smugger than usual. After all, high-intensity intervals have been a training staple for runners since at least the mid-20th century, when Emil Zátopek was banging out quarter-mile repeats to become the preeminent distance runner of his day.
Far less prominent is the humble tempo run, which hasn’t received nearly as much mainstream coverage as its HIIT counterpart but is also essential for runners looking to improve their fitness. Unlike short intervals, tempos are moderately hard efforts that you can sustain for extended periods (up to an hour) without exceeding your “lactate threshold”—that is, the pace at which blood lactate waste starts accumulating faster than it can be flushed out and you begin to slow down. If interval training is about feeling the burn, tempo runs are meant to increase the time you can spend close to the fire without getting too hot.
According to Finley, tempo runs serve a dual purpose: training the body to clear the lactate that’s produced at higher speeds while making it more efficient at pumping blood and circulating oxygen. “It’s about increasing the time you can spend with your heart rate right at the 80 to 90 percent range,” Finley says. “Getting your heart rate up and keeping it at that level.”
The Main Challenge: Finding Your Tempo Pace
“The reason a lot people don’t do tempos, or don’t do them correctly, is because they don’t know what their max heart rate is or what their hour-run pace is,” Finley says. He recommends that runners don’t rely too much on heart rate data—for one thing, it can be difficult to measure accurately—and instead use their half marathon race pace as a ballpark figure for their tempo pace. There are obviously some caveats here as well: if you’ve never raced a half marathon, you’ll have to estimate an achievable goal based on your current fitness. Ditto if your half marathon PR came 20 years ago.
The Solution: Tempo Repeats
While professional runners will often have their ideal tempo paces dialed to the second, the rest of us are unlikely to have the resources or self-knowledge to nail it every time. For that reason, Finley recommends doing progressive tempo repeats with short rests between sets. The idea is to start at a pace that is significantly faster than what you would do on an easy day but still a few seconds per mile slower than your half marathon pace and gradually bring it down with each rep. Ideally, you finish the workout running slightly faster than you might for a continuous tempo.
“For anyone who is not in the top 1 percent of athletes, progression runs are absolutely necessary—both from a warming-up perspective, but also because they protect the workout,” says Finley, referring to the widespread tendency among runners of all levels to start off way too fast.
After a few miles of easy running to warm up, start out with ten minutes at half marathon pace. Give yourself one minute of standing or walking to recover and lower your heart rate. Then run eight minutes slightly faster. Repeat the process for six minutes, four minutes, and two minutes. (If you’re feeling good, do two sets.)
After warming up, run two miles at your current half marathon pace. Give yourself 90 seconds of standing or walking rest. Run two more reps of two miles with a 90-second break in between, each one slightly faster so that your final rep is approaching 10K pace.
A Final Note of Caution
The same principle that holds true for longer races applies here as well: you want to start out conservatively. You can always add another rep if you feel like you took it too easy on yourself, but if you’re fried after rep one, your workout is over.
As Finley puts it: “You want to let the workout come to you—instead of trying to force some idea of a workout onto your body.”