Training adaptations occur as a result of two opposing, but equally important stimuli: overload intensity, and intentional rest and recovery. Without the latter, the body may experience a decrease in performance that could last anywhere from a few days to several weeks.

There are three different ways this performance decrement is categorized:

1. Functional overreaching describes a short-term dropoff in performance (up to two weeks) followed by a supercompensation effect, or significantly improved performance and adaptation.

2. Nonfunctional overreaching occurs on a slightly longer timeline, up to four weeks, and is not followed by a super-compensation in performance or adaptation.

3. Overtraining syndrome is the most extreme case of this phenomenon, extending over four weeks and can last several months.

Built-in rest days are a great way to make sure you are giving your body what it needs in order to recover and adapt. If you are worried about ‘missing out’ on gains, there are a few things you can do to take stock of how well you are recovering.

Sleep

Sleep quality is an important factor to hone in on when seeking muscular adaptations and high performance. When it comes to skeletal muscle specifically, inadequate REM sleep (five hours or less) can result in increased cortisol and a significant drop in testosterone levels after just one week (1). These changes not only have a direct effect on mood, focus, stress, and libido but also lead to negative changes in muscle mass, muscular strength, bone density, and more. Sleep is one of the most underappreciated performance enhancers there is and is a great place to start when examining your habits for recovery.

Blood Pressure & Resting Heart Rate

One characterization of overtraining syndrome is an elevated resting heart rate and blood pressure reading (2). It is easier to monitor these vital signs now more than ever, and making a habit of it on your rest day is a great way to keep an eye on how well you are recovering week over week. If experiencing a noticeable increase in both of these measures, consider building in additional rest, taking stock of your sleep, or consulting your doctor.

Nutrition Audit

If you are reading this article, chances are you have an excellent handle on your nutrition and refueling. However, if you are beginning to feel run down and are experiencing a noticeable drop in energy and performance, it is worth checking in on. A common mistake when training in a caloric deficit is the underconsumption of protein, which leads to inadequate muscle protein synthesis (3). Basically, this means muscles are being damaged and broken down without the proper tools available for adaptation.

Conclusion

The human body is capable of some incredible things, but ultimately one of those capabilities is shutting itself down if too much is asked of it (a self-preservation mechanism). Avoid forcing it into this state by being proactive with your recovery. Your rest days deserve the same care and attention as your training, so build them into your training calendar, use them well, and see your gains continue to roll in!

Citations

1. Leproult, Rachel, and Eve Van Cauter. “Effect of 1 week of sleep restriction on testosterone levels in young healthy men.” JAMA vol. 305,21 (2011): 2173-4. doi:10.1001/jama.2011.710
2. Carrard J, Rigort A-C, Appenzeller-Herzog C, et al. Diagnosing Overtraining Syndrome: A Scoping Review. Sports Health. 2022;14(5):665-673. doi:10.1177/19417381211044739
3. Quaglio, Laura. “19 Signs of Overtraining: How to Avoid Excess Fatigue and Ots.” NASM, https://blog.nasm.org/strategies-for-overcoming-overtraining#:~:text=Overtraining%20syndrome%20is%20characterized%20by,et%20al.%2C%202020). .)