Firm heart rate cap of 120. Why? Oxygen repairs muscles. When muscles are in motion, they can take up to 84% of the oxygen in your blood. At a heart rate of 120, this is hard enough to qualify as 'work' and maximize oxygen uptake but easy enough to not cause fatigue or damage muscles. These runs at slow paces lubricate and heal your joints and are crucial to training at high levels. You are going to need runs at all kinds of paces from this point forward.- Coach MK's standard instructions for a Recovery Run in TP
Let’s talk about recovery time. ☺ This is a neat little feature that is quickly becoming a standard on Garmins, Polars, and other high-level training assessment tools. What is it telling us, how do we use it?
Short Answer: "Be Careful". (Seriously, that's it, that's all it's saying.)
Longer Answer: That's your Injury Window. It's useful but doesn't carry the prescriptive value we want it to (yet). These companies are doing very cool work trying to use data to solve a huge, serious problem, but data alone does not yet effectively communicate problems back to a coach.
Coach MK-Sized Answer:
Overtraining is a widespread problem with no simple solution. For all the advances we have made in exercise and performance-based sports science, coaches still don't have great mechanisms to catch overtraining before a person is already there. It's also worth nothing that currently we don't have an objective data point to accurately capture muscle soreness. Training Peaks will show me how much stress and strain a runner is carrying, but we don't know where that person's tipping point is before we get there.
Ever heard of the 10% rule? This is where it comes from. "Thou Shalt Not Increase a Client's Training Load Week By Week by more than 10%." It's a rule of thumb, not evidence-based science. It's not a bad rule, it's standard practice for a reason, but some people can handle way more, others way less. Takes 42 days before the data in TP is accurate, that's a long time I could be potentially pushing a person well beyond their limits and not know it. I call that period "Trial and Terror."
This matters because distance runners at every level are highly motivated types who will run themselves into the ground before they will admit they are hurting or need a day off. To many, that's tantamount to failure. This is why I consider daily training logs to be paramount- coaches will 'hear' soreness and overtraining in your written logs long before either of us are willing/able to see it creeping up in your data, and by then it's too late.
Read that again: whether hobbyjogger or elite, by the time we realize you are overtrainING, you are already at least 3-5 days overtrainED. It can take five times that to bring you out of an overtrained state. It can take even longer to figure out how you got there in the first place.
The old-school way to check for overtraining was a first-thing-in-the-morning heart rate reading. As in, "turn off alarm, roll over do not sit up, while still in bed slide on heart rate monitor, roll back over and relax, NOW take your resting heart rate and write it in your training log". If your heart rate was 5-10 beats higher than usual you'd warn your coach.
The companies rolling out recovery features and other cool readings like HRV mean well. I believe that. These assessments aren't harmful, but frankly at the moment they aren't helpful either. Those algorithms tell you 'what' with no account for 'why' so they are limited in prescriptive value for coaches.
For example, if your 4yo is having night terrors and you haven't slept through the night in a few weeks, a normal workout may put way more strain on your body than usual. This doesn't mean that the workouts are too hard and your coach needs to back off, it means you need sleep. But your coach has no way of knowing this unless you mention sleep deprivation in your training logs, and most runners won't. Best we can do is ask what's going on and hope you tell us the truth without getting defensive.
Make sense? Sometimes, we're talking about the running. Most of the time though....not so much.
Now, let's pivot back to the recovery figure on your GPS watch.
The time between the conclusion of a workout and full recovery from that workout, when your body is ready to do that same workout (or a harder one) again, is what I call “the injury window”. Polar, and Training Peaks for that matter, are remarkably good at calculating how long the injury window will be (I can’t speak for other devices since I use Polar for myself and Training Peaks for my clients; I haven’t pulled apart Garmin’s methodologies to have an opinion). Anything you do within the injury window is more likely to injure you than make you stronger so we have to be careful.
Here is how I tell my clients to apply the Injury Window concept: "Oh WOW! That was a hard workout. My Vantage V says I won't fully recover from this workout for 72 hours. That's harder than I expected! Will try to go to bed early tonight."
That's it. That's literally, it.
Your watch did NOT tell you not to run for 72 hours. It did NOT tell you that you are overtrained now, game over. It did NOT tell you that you can't/shouldn't do the workout on your training plan 3 days from now. This recovery figure has no prescriptive value, it cannot tell you what to do or what NOT to do.
Here are some VERY general rules of thumb:
An hour at 120 generates a 7-hour injury window
An hour at 140 generates a 14-hour injury window
above that, the injury window varies based on the overall intensity and duration of the workout. Weeks where harder midweek runs are introduced may be accompanied by a shorter long run.
Incidentally, this is why most plans space Tempo runs on Monday or Tuesday and shorter interval efforts two days later with a rest day+easy day in between the interval run and the long run.
When doing hard workouts, we have to mind the injury window very carefully to make sure we’re building muscle rather than breaking it.
This is also why, if you are a fitness/spin instructor or devoted Crossfitter I steer you away from my most advanced plans with the toughest workouts. It’s not about your level of fitness, the injury window is a Honey Badger and don’t care about your fitness level.
Fun fact for those of you training for stacked races and ultras who have two-a-days on your plan- the reason all those 2-a-days are recovery effort, so light it feels pointless, is to sneak in extra oxygen-burning cardio workout time (aka “mileage”) beneath the injury window. These give just as many benefits as making weekday runs longer without increasing the risks of injury. I advise you to space these out at least 7 hours in between the end of the first workout and the start of the second to ensure we are fully recovered from the first before we start the second, and make sure the second workout ends early enough that you’re fully recovered before your workout the following morning.