The Art of The Easy Run
Finding the right pace for your easy runs is important; running these too fast may jeopardize future workout quality and dampen training adaptations to recently completed sessions. Properly paced easy runs enhance recovery, bolster adaptations to hard training, and prepare you for the next hard workout. Easy runs promote blood flow to healing tissues, stimulate beneficial hormone & enzyme release, and improve general cardiovascular & structural endurance. So, how should you find your easy run pace? Unfortunately, there is not an exact formula for this. While there are many online pace charts and "zone calculators" that may tell you an exact pace, it's really nothing more than an educated guess. Depending on your unique physiology, training history, training volume, and more, you may do best with easy runs paced a little faster or slower than "normal". Not all your easy runs should be the same pace either. The duration, proximity to other workouts, and other factors may allow for faster or slower easy runs.
Recommendations for Easy Running:
My general recommendations are below. You can use a variety of systems / metrics to help find the right pace, or a combination of many. Not every method below will yield the exact same results, but for the majority of people, each one will be "good enough".
RPE (rate of perceived exertion). This is simple. On a scale of 1-10, how hard was the session? For easy runs, you should generally be running at an RPE of 4-6.
Pace. There are a lot of ways to calculate a good easy pace based on different race paces. A 1 mile time trial is convenient to test and most people know what their mile pace is within about 10 seconds of accuracy, so this is what I use to calculate easy paces. The vast majority of athletes will do well with easy paces between 40-60% slower than their 1 mile race pace. If you are a fast-twitch dominant athlete or training for your event from the speed side, keeping your easy runs on the slower end (~60% slower) is best. If you are a slow-twitch dominant athlete coming at your event from the endurance side, then "faster" easy runs (~40% slower) are usually okay. If you aren't sure, keeping easy runs right at 50% slower than 1 mile pace is a safe bet.
Breathing Rhythm. Breathing rhythm refers to the number of steps you take per respiration cycle. For easy runs, I recommend using a 5 or 7 step breathing rhythm. A 5 step rhythm should definitely be possible with ease, and a 7 step breathing rhythm may be possible with a little focus. Athletes with a lot of experience using breathing rhythms should eventually be able to hold a 7 step breathing rhythm comfortably on easy runs, but this may be challenging at first.
Heart Rate. Your heart rate for easy runs will typically be between 65 and 75% of your max heart rate. 75% is a good upper limit for easy runs. Extreme heat / humidity may cause your heart rate to be higher than expected, so you should consider relying on other metrics when training in these conditions.
Mindset. Easy runs are an ideal time to destress through moving-meditation. They can also be an ideal time to practice running form and reinforce good habits. Unless you have specific instructions from a coach, the details of how you choose to spend this time, mentally, are not important. The important thing is that you allow this time to be productive. Whether it means exploring new trails with a friend, listening to your favorite music, or refining your skills and technique, do something on every easy run that serves a social, emotional, or physical purpose. Not every runner has the time to regularly practice yoga, but every runner can make an effort to practice mindfulness and awareness during their regular training. The easy run is the perfect time to try since you're unlikely to be distracted by physical discomfort or detailed workout instructions.
The easy run limbo: how slow can you go?
While most new runners fall into a trap of doing their easy runs too fast and not pushing hard enough on other workouts, making your easy runs even easier isn't always the answer. Just how slow can you go and have an effective easy run? It depends who you ask. Many runners will stick to heart rate zones or pace zones for their easy runs, but there are plenty of examples of elite 4 minute milers who still do recovery jogs at an 8 to 9 minute mile. If you're worried that a 9 minute mile is too slow for you, remind yourself that some of the best runners in the world manage to jog that slowly on recovery runs and do just fine. However, most of these runners are also running hundreds of miles each month much closer to or at race pace, so they can "afford" - and need - to do some slow jogs/shuffles from time to time. If you don't run nearly as much, spending a higher percentage of your training time closer race pace is worth the trade off, so easy runs at a faster pace may be best. My genera tips? If you're a low mileage runner, I recommend keeping your easy runs relatively structured and stick to the 40-60% "rule" most of the time. If you run a lot, allowing a few of your easy runs to become "very slow" won't hurt. However, you should also consider swapping some of these out for other forms of active recovery such as aqua-jogging, incline walking, sled pulling, biking, etc.