Runners understandably focus on their long runs while training for races from the 5K to marathons and ultras. Your ability to run long determines how well you run your longest races, and long runs help build the aerobic capability that carries you through races of all distances.
However, the long run also receives too much focus. I’m not going to call the long run overrated, because long runs definitely are not overrated. They’re important. But long runs are one component of a successful training plan, and building your aerobic endurance and performance requires more than getting your long run in every week.
And no, I don’t mean doing your speedwork. In fact, improving your aerobic capability requires no speedwork at all (though speedwork can certainly help your running economy, and is valuable for maximizing your race day speed).
We fixate on the length of our long runs. We fixate on the speed at which we run our speedwork. But we don’t pay much attention to the length of our regular runs, and it turns out the latter is as important (if not more important) to developing our aerobic endurance.
To briefly summarize and blow over a ton of science:
Aerobic development in a distance run usually maximizes from about 60 minutes into a run to about 90 minutes into a run. There is certainly mitochondrial development in runs shorter than 60 minutes or runs longer than 90 minutes, but not as much as that prime window.
And for runs longer than 90 minutes, diminishing returns at some point begin to get outweighed by the physical damage done to a tiring body, especially once glycogen stores begin to run low.
You see elite long distance runners putting in 80-120+ mile weeks and doing 12 mile midweek runs, but what many people overlook is that they’re finishing those midweek runs in 60-90 minutes. They can run their easy runs at a 6-7 minute per mile pace. A 12 mile run for a world class runner whose easy pace is 6:30/mile takes less than 80 minutes. Sure, that runner’s recovery runs are 4.5 miles, but if they’re “coasting” at 7:00 per mile, that recovery run is over in about half an hour.
Meanwhile, if you tried to stretch out and do a 12 mile midweek run when your typical run pace is 10:00/mile, you’re going to be out there two hours. And that’s certainly too much for just a regular run when you’ve got several other (likely tougher) workouts to do that week.
Likewise, you might see the elites doing 20 reps at 800 meters and think you should build up to the same. But that elite’s running those reps at a 5:00/pace and finishing those reps (with rest breaks) in about 75-90 minutes.
If you need 4 minutes to run 800 meters and you try to do this workout, you’re going to be out there over 2.5 hours, if you don’t collapse from exhaustion first.
That’s a bit of a tangent, but I point this out to note that when an elite logs 20-24 miles in a long run, their easy running pace allows them to knock that run out in 2.5 hours. It’s not that much more demanding for them than their other workouts. You, meanwhile, may take 4 hours to run that kind of distance, and that workout will certainly be a monster compared to the rest of your training plan… if it doesn’t derail subsequent workouts entirely.
It’s more valuable for most runners to focus on maximizing the time in their regular runs than to try and max out their mileage on their longest runs.
This does not mean you should do your regular runs faster. Absolutely not! Any sustained attempt to outrun your current pace capabilities will just get you burned out or injured.
The point is not to say run as many miles as you can on midweek runs, but to aim to run easy for up to 60-90 minutes on those regular runs as consistently as possible. You do just as much for your aerobic development by hitting that sweet spot every day you can, as you do with speedwork or by trying to max out the long run.
In fact, if you get your long run to, say, 1.5 to 2.0 hours (90-120 minutes)… you could just leave your long run at that distance/time for a while, and focus on stretching out your midweek regular runs as reasonably as you can.
If you usually run 30 minutes, gradually stretch them out at an easy pace until you get to at least 60 minutes. If you already run about 60 minutes a day, try to get one or more of your regular runs up to 90 minutes.
Don’t worry about running faster at all. In fact, you might even want to pull back on your pace a bit and run even easier while stretching out (again, most runners do their long runs too hard and too fast… yet wonder why they get injured or burned out so much).
Just focus on maintaining an uninterrupted easy run for the needed time. Your pace will naturally improve as you get more physically comfortable with running longer periods of time. This will take time.
But, if you struggle with your long run, you may be better off keeping your long run at the longest distance you can consistently run… and focus instead on boosting the amount of time you spend on those easy runs.