Hey hey readers! I am so glad you are here! In this month’s blog post, which is part 2 of my Recovery in Fitness blog series, I will give an overview of what happens in our bodies when we recover from our physical training. If you haven’t read part 1 of this series yet, you might want to check that out first (click here), so you are all caught up with what recovery means from a fitness perspective.
Physical fitness training, whether that be running, cycling, swimming, or something else entirely, essentially should involve two components – stress (from the workouts themselves) and rest (aka recovery). To adequately train, the body MUST recover from that training. Recovery is where the gains from your training actually occur. Professional and Olympic athletes know the importance of incorporating recovery into their training regimen, but a lot of recreational athletes still tend to overlook this super important aspect of training. And listen, I totally get it. Recreational athletes are typically working full-time jobs outside of their training and/or raising kids, so time is definitely a factor. Plus, recovery isn’t as “exciting” so to speak as say tracking your weekly swimming or running mileage. But, without adequate recovery, the body will not adapt at all, or as well, to the training, and injury and burnout are way more likely. Thus, prioritizing recovery into your training plan is key to both your short-term and long-term success, regardless of what sport or fitness endeavor you engage in.
A lot of really cool and fascinating things happen in our bodies immediately following a workout as well as in the days and weeks following a workout. But, these events can only occur if the body is given time to recover. So, let’s talk about what happens biologically and psychologically during recovery. Stay tuned for part 3 of this series (released in December 2024), which will go over different evidence-based strategies for recovery.
Recovery is a Two-Part Process
So, recovery from a workout can be thought of as a two-part process. The first part of recovery occurs right after finishing a workout, where the body works to reestablish homeostasis (aka balance). This so-called homeostasis recovery begins within minutes after finishing your workout, and can last for approximately several hours. The second part of recovery occurs over the days and weeks following exercise, where the body adapts and responds to the repeated exercise. This so-called adaptation recovery is where the gains are made from the workout and where the body begins to make cellular, physiological, and psychological changes so that the next time you workout, the body is better able to handle that stress. Because adaptation occurs outside of the actual physical workout, inadequate recovery means inadequate adaptation. If enough recovery is provided between stressors (aka workouts), muscles, tendons, bones, and other tissues can recover and adapt, and injury is way less likely to occur. Let’s chat about each of these two parts in greater detail below.
What Happens in Homeostasis Recovery?
During the first stage of recovery, the body works to restore balance. Immediately following a workout, especially an intense one, fatigue is high. The mind and physical body have been stressed during the workout (and I am using the term “stress” here in a positive way), which put pretty much all bodily systems a little out of whack. Over the next few hours or so, the body will work to return all these systems back to their happy, resting state.
Right after the exercise ends, the body is compromised physically and mentally, and it needs rest. For example, muscle glycogen (i.e. the storage form of carbohydrates used in our bodies for work) is depleted, or at least diminished greatly. Cortisol levels are elevated because the sympathetic nervous system (SNS) was activated, which is the body’s stress response system (aka fight-or-flight system – click here to read more about this division of the nervous system). The SNS causes the release of cortisol and adrenaline, as well as a host of other changes in the body, to accommodate and navigate the stress the body is under. Neurons (i.e. nervous system cells) show decreased activation. Serotonin levels are reduced in the brain, which causes mental fatigue. And so much more.
Over the minutes and hours following the workout, the homeostasis recovery begins. Basically, the body returns all of the altered systems back to their usual functioning. For example, here are some things that are restored during this early phase of recovery (and side-note, these specific actions are a huge reason why your post-workout nutrition matters so much – it allows these things to return to normal so much easier, but more on that in part 3):
Heart rate and body temperature decreases (this is why a cool-down of some type is super important after your workout).
Glycogen, creatine phosphate (i.e. an important molecule involved in a certain type of anaerobic energy production), and the body’s “ready-to-go” cellular ATP get resynthesized (this is where that post-workout carbohydrate snack is super important).
Intracellular (i.e. within the cell) electrolyte (e.g. sodium, potassium) concentrations get restored (this is where consuming something with electrolytes post-workout can help, such as Gatorade).
The acid-base balance of the blood and tissues gets restored (this is where breathing exercises can be really helpful).
Any tissue damage from the stress gets repaired (this is why protein is so important for post-workout nutrition).
Psychological restoration begins to occur, where neurotransmitter levels return to baseline, and the mind itself gets a break from the stress, renewing the desire to keep training.
Also, interestingly, the body consumes more oxygen after the workout, even more than when the body is at rest. This extra oxygen consumption is needed to restore and reestablish homeostasis. This phenomenon is known as excess postexercise oxygen consumption (EPOC). So, now that the body has returned to its resting state, so to speak, what occurs in the days and weeks, or even months, following exercise?
What Happens in Adaptation Recovery?
The human body is wonderful at adapting to stress, as long as it is given enough recovery time between doses of that stress. If not enough recovery time follows the stress, exhaustion, injury, and/or burnout can result. Many people use the term “overtraining” to describe a condition in the body from too much intense training without recovery, but what might better explain what’s going on in the body from that scenario is really “under-recovery.” There has to be recovery between intense workouts in order to actually reveal the effect of the hard training you’ve done. I can absolutely attest to this, personally. I have always been a distance runner. In my 20’s, I ran many half- and some full marathons, but I had zero recovery practices. I was almost always getting injuries, like shin splints, or muscle pain, like in my hip flexors. I plateaued in my running, and sometimes found running to be more of a chore than something that felt amazing. In my 40’s, in which I now include recovery work in to my training, I can run longer, and it is so much more enjoyable. I am able to swim and cycle and do triathlons. I am a way stronger athlete now at age 41 than I was at 21, and this is because of my recovery. I allow my body and mind time to adapt from my training, so my training actually improves. And, I stay injury-free.
So, how does the body adapt? Muscle cells can detect a variety of signals during exercise, including mechanical, metabolic, neural, and hormonal signals. These different signals ultimately lead to different genes (and subsequently proteins), being expressed as a way for the body to better cope with the stressors imposed on it during training. There are many many cellular steps and events that occur leading to the eventual production of proteins (as the image below shows), but that is way outside the scope of this post to discuss. So, for the purposes of this post, just know that exercise-induced cell signaling results in an increased accumulation of various proteins in the cell. Once the proteins are produced, they then get transported to the different places that they will function inside the cell to either be used for structure (e.g. myosin or actin filaments used in muscle contraction, as is the case in strength training – click here to read more about these muscle proteins) or function (e.g. to create more mitochondria to be used for aerobic energy production, as is the case in endurance training). These increased proteins allow the body to be better able to cope with the demands of your training, so that your training and fitness improves, and you can remain free from injury.
So, what adaptations occur when recovering from training? Well, truth be told, the specific adaptations will largely depend on the specific workout being completed, although there are some overlap and commonalities. I myself am a long-distance runner and swimmer, as well as a yogi, so my knowledge of training adaptations is much greater for these particular sports and movement practices. Thus, that is what I will discuss here in this post. However, some of these adaptations will also be seen in other forms of training, such as resistance training and team sports. For a more thorough overview of the adaptations caused by exercise other than endurance work, I would recommend the reader check out PubMed for published scientific articles in the sport of your interest (e.g. for resistance training adaptations, try searching “adaptations from resistance training” into the search line on PubMed). Below is a very simple summary of some of the adaptations that occur from endurance training during the adaptive recovery period:
Mitochondrial biogenesis – aka the creation of new, additional mitochondria as well as current mitochondria increasing in size, which enhances one’s ability to generate energy aerobically, increasing aerobic power (VO2 max), fat-burning capacity, and aerobic capacity – this translates to being able to run for longer, at a faster pace, with less fatigue; even just one long run causes a cascade of molecular events to trigger mitochondrial biogenesis.
Muscle capillarization- aka the creation of new capillaries (i.e. the tiny, little blood vessels surrounding and traversing individual cells, sort of like a spider web) around muscle cells. The increased muscle capillaries result in more oxygen getting inside the muscle cells much faster, and this oxygen can then be used to help power the aerobic energy-producing pathways in the mitochondria. Endurance exercise is one of the few circumstances that prompt an expansion of this capillary network. The sheer stress and mechanical forces applied to the capillaries from the constant “push” of blood through these small vessels during endurance exercise triggers new vessels to sprout from existing vessels, creating a larger “highway system” (so to speak) for delivering oxygen to the muscles.
Greater fuel storage – running long enough causes depletion (or severe lowering) of muscle glycogen, the stored form of carbohydrate. Since carbohydrate is the muscles’ preferred source of fuel, getting low on glycogen is bad for muscle function – think “hitting the wall,” which if you’ve ever experienced that as an endurance athlete, you know how terrible that feels. So, endurance training causes muscle cells to synthesize and store more glycogen than was previously present, increasing your endurance and ability to run for a longer time. It’s like emptying a full glass and getting a refilled with a larger glass in its place, and this adaptation occurs during recovery.
Greater reliance on fat – when muscles run out of carbohydrate, they’re forced to rely on fat to produce energy for muscle work. Endurance training, especially beyond one hour in length, causes the body to become better able to efficiently use fat for fuel during workouts. This is partly due to mitochondrial biogenesis, but also due to increased enzymes in the fat oxidation pathways as well as increased ability to transport fat to, and within, the muscle cell. This adaptation is actually very important for long-distance runners because fat yields far more ATP (i.e. the energy currency used in the body to create work) than carbohydrates do, allowing the runner to run for longer, at a faster pace, without getting fatigued.
Stronger muscles, bones, tendons, and ligaments – endurance training, especially running, can be tough on the muscles and joints, so these tissues adapt during recovery by becoming stronger to handle the stress of pounding the pavement. Remember when I mentioned how some proteins produced during adaptive recovery are used for structure? Well, during adaptive recovery, some of these proteins are used to reinforce the structure of muscles, tendons, ligaments, and bones. This translates to less risk of injury and stronger tissues to endure the higher mileage/intensity from your endurance training.
Erythropoiesis – aka the formation of new red blood cells (RBCs). When you exercise aerobically, like run or cycle, on a regular basis, you make more RBCs, and you increase your total blood volume, both of which increases your ability to transport oxygen, which is absolutely necessary for helping to power aerobic energy-producing pathways in the mitochrondria. More oxygen delivery to muscle cells translates to more energy produced (via aerobic pathways), which leads to faster, longer, and more intense training before you fatigue or risk injury.
Greater psychological strength – when someone runs for a long time, or cycles or swims, his or her legs/arms aren’t the only body parts that get tired. The mind fatigues, too. One of the large adaptations that occurs during recovery is an increase in mental fortitude and a renewed desire to keep training and to train harder. I have definitely felt mental burnout from overtraining (aka under-recovery), and it is legit real. After my first marathon in my early 20's when I did not do any recovery work, I was so under-recovered that I didn't want to even think about running for months, so I had to take a several-month break from running. But, after my recent marathon that did include recovery work, I was so excited to run again just two days after the race. Point is, recovery makes a massive difference for the mind. Don't ignore your recovery!
Of course there are many other adaptations that occur from endurance training specifically and exercise in general. The list described above is just a sample of some of the amazing things that occur in the body during adaptive recovery. Without adequate recovery time, these wonderful adaptations would not occur, resulting in your training plateauing, your mind developing burnout from your training, and your body likely getting injured. If you want to perform better, you must must must allow adequate time to RECOVER! See below for an image of the different parts of a typical, skeletal muscle cell, including the capillary, mitochondria, nuclei (where the DNA is housed that ultimately leads to the production of proteins), and the muscle filaments, where the actual contraction occurs (e.g. myson, actin), as these are some of the cellular components that can change during the adaptive recovery discussed above.
Summary
Wow! That was a lot of information, so thank you so very much for sticking with me until the end of this post. I am a huge believer in the power of recovery work. As I stated in part 1 of this post, as well as in this post, I am a perfect example of the benefits of doing regular recovery work and how one’s performance can suffer greatly without recovery work. I know how hard it is for an athlete to take a break and allow time for resting and recovery. It takes a certain level of patience and faith that your body really does need this time to heal itself and that this time away from training will actually improve your training. There are many factors that influence how quickly and completely an athlete recovers from their workout, including age (younger athletes tend to recover faster), training intensity (more intense training typically requires longer recovery time), environment (altitude and cold weather can slow recovery), nutrition/hydration (better nutrition and hydration speeds up recovery), psychological stress (more stress slows down recovery), and level of cardiovascular fitness (better cardiovascular fitness causes faster recovery since recovery is an aerobic process). Treat recovery as a vital part of your training, which it should be. Try approaching your recovery work with the same diligence, discipline, and excitement as you do for your regular training routine. Letting go, resting, and relaxing are so important for your short-term and long-term success as an athlete. If you want to reap the benefits from all your hard work during training, then you must recover. There is no other way around that. Just like you honor your body by pushing it to its limits during training, be sure to honor your body by allowing it time to heal, repair, and restore. Thank you so much for reading this post! Stay tuned for part 3 to be released in December, which will go over the different evidence-based recovery strategies that you can employ to have a long-lasting, fulfilling exercise career.
As always, the information presented in this blog post is derived from my own study of human movement, anatomy, and yoga. If you have questions about recovery work for your body, please follow up with your physician, physical therapist, or personal trainer. If you are interested in private yoga and/or personal training sessions with me, Jackie, email me at info@lotusyogisbyjackie.com for more information about my services. Also, please subscribe to my website so you can receive my monthly newsletters (scroll to the bottom of the page where you can submit your email address). This will help keep you "in-the-know" about my latest blog releases and other helpful yoga and wellness information. Thanks for reading!
~Namaste, Jackie Allen, M.S., M.Ed., CCC-SLP, RYT-200, RCYT, NASM-CPT, NASM-CES
References:
Roundtree, S. (2011). The Athlete’s Guide to Recovery – Rest, relax, & restore for peak performance. Velo Press. Boulder, CO.
Karp, J.R. (2022). Foundations and Applications of Running Technique and Programming. International Sports Sciences Association. Phoenix, AZ.
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