In order to understand the role of rest and recovery time, it’s important to acknowledge exactly what occurs in the body physiologically during and after exercise.
During exercise, the body is challenged and pushed slightly beyond its current limits. This stress creates slight trauma and micro-tears to the muscle and tissue. But when that muscle and tissue is repaired, the body grows stronger and its limits expand.
Therefore, the key to growing stronger is putting just enough stress on the body that the muscles need repair, and then allowing the body time to recover. This recovery time is not only vital to muscle repair— exercise also impacts digestion, hormone regulation, kidney function, immunity, and more, so it impacts the entire body. Without allowing enough rest and recovery time between workouts, the body may not repair properly, which can affect muscles, sleep, mood, and energy levels.
So, when does the body need a break?
Abnormal Heart Rate
Hands down, the best indicator of overtraining or the necessity of a rest day is your heart. Both Resting Heart Rate (RHR) and Heart Rate Variability (HRV) can guide you. Check each of these vitals on training mornings. A higher than normal RHR indicates overtraining, potential hiccups in your current training regimen, or even an oncoming illness.
The body also indicates when it needs a break with a low HRV. An intense workout can keep your heart rate variability low for days as the body recovers. Rather than putting yourself at risk of overtraining, which can lead to muscle damage or mood imbalances, heart rate variance data can keep you active at the most opportune of times. Remember, HRV can be counter-intuitive and the higher the variance— or more sporadic the heartbeat— the better. Low variance in between heart beats— that is, a consistent heartbeat— indicates a dominance of the sympathetic nervous system. This system’s primary process is to stimulate the body’s “fight-or-flight” response but, when experienced without a threat, is signaling stress, overtraining, and inflammation.
With most types of training and cardio, muscle soreness is to be expected, but it’s also another strong sign of the need for recovery time. The key is to put just the right amount of stress on the body, or train just above but not too far beyond your current ability. Soreness is a sign of stress on the muscle that is undergoing repair, which generally should take one to two recovery days for a challenging workout. It’s important you do not train sore muscles, as they are not adequately repaired. Instead, work different muscle on groups on different days, so the previous groups have time to recover before you work them out again. After an intense full-body workout which leaves the entire body sore, take the rest day.
Every body is different and only you can know how you feel from day to day. Trust your instincts and pay attention to your body. If you feel sore, fatigued, just out of sync, or Biostrap indicates abnormal Resting Heart Rate or Heart Rate Variability, take the day off— your body will thank you.