Rest and recovery days are equally, if not more important than workout days. Only with these days in your schedule, will you be able to train in a quality way on your hard days. Many people beginning their running journey either rest too much or too little, but many highly driven individuals have a hard time giving themselves the rest they need and deserve. Let's first look at the benefits of rest and recovery days, then discuss possible reasons why people don't give themselves enough of this.
Stress + Rest = Growth
This concept can be applied to many things in life. Specifically with regard to running, a hard workout is stress, and requires rest and recovery in order to improve. In fact, your body will try to improve itself in a process called supercompensation, in order to better tolerate the workout load next time. If you do not give yourself the rest you need, you body will plateau and eventually decline. Remember, this concept applies not only to individual workouts, but also to training blocks as fatigue is cumulative. That means you not only require rest and recovery days built into your schedule after hard workouts, but you also need rest and recovery weeks built into your training cycles. When you don't give yourself these necessary components to training, you put yourself into a negative cycle in which your body undercompensates, unable to make gains, resulting in stagnation, overtraining, and you will not improve.
Fatigue: Tissue Breakdown, Cardiovascular, Musculoskeletal, Hormones, and Mental Fatigue.
When you have a hard training day, your muscle tissue breaks down, you deplete glycogen stores in your muscles, you get tired, your tendons and bones have been highly impacted, your heart has worked hard, your hormones/adrenals have been taxed, and you've put in a serious effort mentally. All of these systems require rest, recovery, and require different forms and amounts of rest and recovery. For instance, in order you replenish the glycogen stores in your muscles, you must immediately eat good carbohydrates after a hard training session. In order to rebuild the tissue breakdown and musculoskeletal system after high impact, nutritious BCAAs and quality sources of protein is necessary. To repair that mental fatigue from a hard effort, you may need a long shower, some meditation time, or maybe a snuggle with your dog. With regard to hormones, different forms of exercise effect different hormones. For example, intense workouts increase cortisol levels, while easy runs decrease cortisol. This means actually easy runs, not too-fast-for-easy-runs that you've somehow convinced yourself are easy even though they're really moderate, or even hard when your body hasn't fully recovered.
Supercompensation
After a hard workout, your body is initially in a deficit and requires rest and recovery to bounce back from that stimulus. This resilience building cycle is called supercompensation. You essentially tax your body to the appropriate degree, at a maximal effort, then your body adapts to be able to perform the same task or harder task. This looks like a wave that gradually get higher and higher at each crest. If you push yourself too hard, your body won't be able to adapt to improve, and will stagnate. If you push WAY too hard, your body will remain in a deficit. If you don't push hard enough, you will also stagnate. Finding that sweet spot is really important. Additionally, if you do another moderate to intense effort before your body has supercompensated, you will decline and will get no benefit from your hard work.
Rates of Recovery
Studies show that it takes a full 24 hours to recover from a standard bout of exercise, NOT a maximal effort. It can take from 2 days to 2 weeks to recover from a true maximal effort. What impacts a person's rate of recovery? Factors include but are not limited to: age (it takes longer to recover the older you get), quality of sleep, quality of nutrition, being a woman (men recover faster due to higher testosterone), other stress. Remember, your body doesn't know the difference between good, exciting stress, work stress, exercise stress, etc. If you run too hard or too long on your recovery days, you are preempting the supercompensation phase and not allowing yourself to reap the benefit of your hard work.
Why Don't People Give Themselves the Rest & Recovery They Need?
-The individuals who are so highly driven, often need to be reigned in. Often, these individuals will run their recover runs too hard or too long, then they under perform in their next hard training day, and instead of giving themselves rest, they push even harder in their next recovery run. Logically, this does not make sense. To keep pushing harder when your body is unable to perform? It would seem obvious that the body needs rest. But often, human beings do not act in logic, we act in emotion. These highly driven, highly motivated individuals has convinced themselves they must work harder. This creates a loop that is inescapable until they've completely burned themselves out or broken themselves and need to take an extended break.
-People may understand on a cognitive level that by foregoing rest days & by running recovery days too hard or long, that they are doing damage, yet are unable to refrain from doing so! This decision may not be guided by logic or sense, but by emotion and psyche. The masochist may unconsciously perceive their underperformance in a workout as something that needs to be reprimanded by pushing harder, doing more, not deserving the rest and recovery.
-The need to be a human doing and not a human being is real. Some times, doing nothing, (even if you're actually doing something very important) is intolerable. What happens when you rest? What happens in your head when you sit still? What happens in your mind when you are not going, moving, doing, and just being with yourself? This is a real thing that we need to evaluate within ourselves. What happens in our brains when we slow down? These thoughts and feelings that come up can make a serious impact on our willingness to take action, sometimes promoting too much action. Repairing this requires active attention as well. Some times scheduling meditation or restorative yoga or a rolling session in place of a run or cross training session is a necessary change to implement. These things ALSO make you stronger.
Bottom line is, we are complex creatures. We need to train our whole being. Giving yourself rest is incredibly important. I mean, think about it...we sleep A LOT. We wouldn't do that if it wasn't a necessary part of every day life. Rest is necessary.