Going out for a second run of the day may hardly sound like recovery. What is a recovery run, anyways, and what’s the point? How do you distinguish between junk miles and recovery miles? Understanding this workout and the benefits it can provide can help you level up your running, recover faster, and increase your running fitness.
Why Do a Recovery Run?
Recovery runs are best executed after a moderate- or high-TSS effort like a workout, race, or strength training session. Endurance athletes often suffer from sore muscles after these types of workouts, and recovery runs are meant to loosen up the body by increasing blood flow and flushing out waste. This is vital to performance, as stiffness and soreness can limit your mobility, diminish your power output, and make workouts uncomfortable and daunting to complete.
When you work out, especially at high intensities, several physiological processes take place that increased blood flow can help remedy, as seen in the chart below.
For athletes that are training more than 50 miles per week or practice multiple sports (like triathletes and duathletes), a recovery run can be a great way to flush the major movers and jump-start the recovery process.
How Are Recovery Runs Different From Easy Runs?
There isn’t a distinct difference between an easy aerobic run and a recovery run other than the intention of the workout. Your day-to-day aerobic run that’s solely focused on maintaining a Zone 1 or Zone 2 heart rate meets the definition of a recovery run. However, an aerobic run and recovery run begin to look different when they are completed.
Recovery runs — which generally consist of 20-30 minutes of aerobic running — are intended to follow a hard effort as a way to remove waste (as covered above). Runs longer than 30 minutes begin to produce metabolic waste and, depending on your fitness level, can take you longer than 8-12 hours to recover from. These types of runs certainly don’t qualify as recovery runs!
Active v. Passive Recovery
There are two types of recovery: active recovery and passive recovery. Going out for a recovery run, completing an easy spin on your bike, or doing 20-30 minutes of yoga are examples of active recovery. Using a percussion massager or compression boots, taking a nap, or getting a massage would be considered passive recovery.
The biggest differentiation is that active recovery increases heart rate and blood pressure, resulting in vasodilation (i.e., the dilation of blood vessels) and the transportation of metabolic waste.
Which Is Right for Me?
How you choose to approach your recovery should always come down to understanding your body and where you’re going to get the most value. If you’re physically beat up from your last run, an easy run may not provide recovery and instead could increase your recovery time. The variables to consider are numerous, and it will take some experience to determine if a recovery run is the best solution to optimize your recovery.
If you’re injury prone or currently run less than 24 miles per week, a 20-30 minute recovery run might actually put you in a worse position. If your body has a tough time recovering from high-impact sports like running, you might want to consider an easy ride or yoga session as a recovery option. Conversely, if you’re training between 40 and 60 miles per week, a 20-30 minute run later in the day after a difficult workout might be the right fit to help you increase mileage, recover, and get an additional training benefit.
*A special note for ultrarunners: training on tired legs is commonplace and often a desired training state. If you’re curious to learn more about how we generate fatigue, you can listen to one of my recent podcast episodes, The Biology of Fatigue, on the Defining Endurance Podcast.
Does Sex Influence Recovery?
In short, yes. A recent study compared a population of men and women after a half marathon to assess muscular function, power development, and the influence of delayed onset muscle soreness. The greatest finding was that the women, on average, showed earlier functional recovery than the men. This is potentially due to the fact that women have lower muscle mass, force, and power output than men at the same relative intensity and are therefore considered less fatigable. This may also be due to the direct and indirect influence of sex hormones (i.e., estrogen versus testosterone), which in women produce a lower amount of metabolites and metabolic waste. The aforementioned study showed that estrogen might lower the impacts of exercise-induced skeletal muscle damage, therefore reducing the impacts of delayed onset muscle soreness (DOMS) as compared to men.
One of the greatest influences on recovery for female athletes is where they are in their menstruation cycle, as fatigue is higher during menstruation. Menstruation also plays a role in metabolic demands during recovery. One study showed that menstruation raises basal metabolic rate by more than 6%, which will have a significant impact on glycogen stores, recovery, and overall perception of fatigue. This increase in caloric demand occurs over a period of three to five days as women move through their menstrual cycle, which can complicate fueling procedures leading into and during a race. If you want to learn more, check out this podcast about how ultrarunner Camille Herron raced the Western States 100 on the first day of her period.
Using Metrics to Assess Recovery
Assessing the quality of your recovery requires experimentation and introspection; there is no specific metric that can truly determine your ability to perform. However, using a metric like TSB (aka, Training Stress Balance or Form in TrainingPeaks) can give you a guesstimate of how you’ll feel in your next workout and ultimately give you a gauge of how ready you are to perform at race-level effort. The closer your TSB is to a score of 0, the more recovered you are. On the other hand, a score of -20 or -30 indicates that you need to take a few easy days to recover your body.
At the end of the day, performance can only improve by applying stress to the body and then recovering adequately. Increased adaptation to training stimuli leads to improved fitness as well as the ability to manage greater fatigue. In other words, the fitter you get, the less time you need to recover.
So, it can reasonably be said that a true recovery run can exist, meaning you can simultaneously apply a small stress load, increase blood flow to muscles, and recover. Simply put, recovery runs are a straightforward way to get real performance benefits.
References
Macchi, R. et al. (2021, March 18). Sex Influence on the Functional Recovery Pattern After a Graded Running Race: Original Analysis to Identify the Recovery Profiles. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8012843/
Romero, S.A. et al. (2017, February 2). The cardiovascular system after exercise. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5407206/
Solomon, S.J. et al. (1982, October). Menstrual cycle and basal metabolic rate in women. Retrieved from https://pubmed.ncbi.nlm.nih.gov/7124662/
