The category of sports nutrition continues to evolve and grow. From following at-home videos to hitting local gyms, exercise is on the rise among consumers. Athletes and active consumers looking to perform at their best need to understand that recovery is one of the secrets to success.
While exercise may be the trigger, building and restoration take place in recovery. Intense bouts of exercise tax the body’s muscles and joints and deplete nutrient and energy stores. Three underlying mechanisms mediate post-exercise recovery: skeletal muscle damage, decreased nutritional substrates and accumulation of metabolic byproducts.
Skeletal muscle damage
When muscles undergo intense exercise, such as from resistance training, resulting trauma impacts the muscle fibers. This is a healthy and natural process in muscle growth and development. After a workout, the body starts repairing and replacing damaged muscle fibers through a process in which new muscle fibers are fused together to form new muscle protein strands known as myofibrils. As these new myofibrils increase in number and thickness, the result is muscle hypertrophy, or muscle growth. However, this muscle growth does not occur during training—but rather after, while the body is at rest.
Energy is created to support activity through three main energy pathways.
- Phosphagen system: This energy pathway is the most rapid means for generating and regenerating adenosine triphosphate (ATP), the energy currency of the body. A single reaction occurs whereby the enzyme creatine kinase (CK) catalyzes the metabolite phosphocreatine (PCr) to create ATP. This energy system is utilized during high-intensity activities like sprinting or strength training because ATP is produced quickly and is readily available to the body.
- Glycolysis: This is the second-fastest system for ATP production. Glycolysis is slower at creating energy than the phosphagen system because it includes nine enzymatically catalyzed reactions and has two phases, an energy investment phase and an energy generation phase. Glycolysis is used as the main supply of energy during sustained exercise such as walking.
- Mitochondrial respiration: Also known as aerobic respiration, this pathway is the slowest in terms of ATP production. This form of energy production is a set of metabolic reactions and processes that require oxygen to convert energy stored in macronutrients into ATP. Aerobic respiration is typically used during aerobic exercise such as swimming, running or cycling.
Exercise taxes all three energy pathways. Each pathway has primary substrates needed to generate ATP. During a workout, these substrates are utilized to create energy and support activity. It’s important to ensure adequate substrates are available because the one thing athletes do not want to fall short of is energy.
Accumulation of metabolic byproducts
The ATP turnover rate is elevated during high-intensity exercise. This increased production of ATP results in an accumulation of byproducts, resulting from the various energy pathway systems. One such byproduct is reactive oxygen species (ROS) or free radicals that result from muscles burning calories through oxidation. These free radicals can cause damage to muscle fibers and reduce their ability to contract.1 Other byproducts created during exercise are lactate and hydrogen ions or protons. The production of muscle force depends on contractile mechanisms at cross-bridges within the muscles,2 and lactate and protons can hinder skeletal muscle contraction as they contribute to changes in cross-bridge activity.3
Skeletal muscle damage, decreased substrates and accumulation of metabolic byproducts are all normal responses when the body undergoes intense exercise. The challenge then becomes combatting potential related effects such as post-workout fatigue, inflammation and muscle damage. A variety of ingredients on the market today address the various concerns of exercise recovery.
Ingredients for exercise recovery
One thing athletes do not want to fall short of is energy. A host of nutrients support the energy restoration process within the body.
- Creatine supplementation has proven beneficial in helping athletes recover from intense training. During high-intensity activities, the phosphagen system metabolizes PCr to generate ATP for energy. By supplying the body with supplemental creatine, the body is then able to generate more PCr, thereby increasing energy production. Researchers from Queen's Medical Center, Nottingham, UK, found among 24 males that co-ingesting 5 g of creatine with 95 g of glucose enhanced overall creatine and carbohydrate storage in muscle.4 In addition, Nelson and colleagues examined two glycogen loading protocols among 12 men (ages 19 to 28) and found that creatine loading prior to exercise alongside glycogen loading promoted greater glycogen restoration than carbohydrate loading alone.5
- Highly branched cyclic dextrin (HBCD) can ward off energy shortage by providing quick and sustainable energy. A 2015 study on seven male elite swimmers (ages 18 to 22) demonstrated time to fatigue was 70% longer in the group receiving HBCD when compared to those receiving glucose or water.6 These results suggest that HBCD may help reduce fatigue in athletes following strenuous exercise.
- For those seeking a ketogenic-friendly option to replenish energy stores, medium-chain triglycerides (MCTs) may prove popular. Nosaka and colleagues investigated the effect of two-week ingestion of food containing 6 g of MCTs on energy metabolism during moderate- and high-intensity exercise in recreational athletes.7 Results demonstrated the ingestion of MCTs may suppress the increase in blood lactate concentration and rated perceived exertion (RPE) during moderate-intensity activity and extend the overall duration of high-intensity exercise.
Inflammation is a big concern for athletes and active consumers following a workout, competition or strenuous activity. Damaged tissue can trigger inflammation, which also has a relationship to oxidative stress, which is an imbalance between the production of ROS and their elimination. This imbalance can promote inflammation within the body. Several natural ingredients can help address this imbalance and reduce inflammation.
- Alpha-lipoic acid (ALA) has gained considerable attention as an antioxidant offering many potential benefits. A study with 13 trained and 20 untrained men evaluated the antioxidant effects of ALA supplementation and found it may diminish oxidative damage.8
- Curcumin is a natural compound that has shown some promise in exhibiting anti-inflammatory effects. In a study with 10 male participants, Takahashi and colleagues found that biological antioxidant potential concentrations were significantly elevated following exercise in the curcumin-supplemented group.9 These findings indicate that curcumin supplementation may attenuate exercise-induced oxidative stress by increasing the blood’s antioxidant capacity. In an additional study, 28 male participants were recruited to assess the effects of curcumin on acute exercise recovery, specifically delayed-onset muscle soreness (DOMS).10 Results demonstrated curcumin may elicit anti-inflammatory properties that aid in reducing pain experienced by athletes, allowing them to return to training and activity sooner.
- Montmorency tart cherry concentrate may prove to be an additional natural ingredient to address post-exercise inflammation. Bell and colleagues examined the ingredient’s impact on oxidative stress, inflammation and muscle damage across three days of simulated road cycle racing among 16 trained cyclists.11 Blood samples collected at baseline and immediately pre- and post-trial showed reduction in overall inflammatory markers, suggesting the tart cherry concentrate may prove efficacious in combating post-exercise oxidative stress and inflammatory responses.
During training and exercise, muscle fibers are torn and nutrients are diminished. Addressing this muscular damage and replenishing nutrients lost during training is key in enhancing overall recovery.
- Omega-3 fatty acids have been associated with healthy aging throughout one’s lifetime. Omega-3 long-chain polyunsaturated fatty acids (LCPUFAs), including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are dietary fats that may aid in increasing the rate of muscle protein synthesis (MPS). In a study of 16 healthy older adults, subjects were randomly assigned to receive either omega-3 fatty acids or corn oil for an eight-week period.12 Results demonstrated omega-3 fatty acids increased muscle anabolic signaling activity.
- Dietary protein plays many important roles in countless physiological processes within the body. The popularity of protein supplementation continues to rise as consumers desire increased muscle mass, improved performance and improved markers of recovery. Consuming adequate protein after exercise is essential for maximizing MPS and maintaining net protein balance. In a double-blind, placebo-controlled study with 12 healthy young men, results showed that whey protein supplementation enhanced whole-body net-protein balance over 10 hours of overnight recovery and enhanced recovery exercise performance.13
- The role of magnesium in muscle function has been studied extensively throughout the years. Magnesium participates in the process of energy metabolism and assists in the maintenance of healthy muscle contraction and relaxation. Restoring magnesium levels in the body may enhance athletic performance as it is a co-factor in more than 300 enzymatic reactions, including energy production.14 Lindsy Kass, senior lecturer at the University of Hertfordshire, and colleagues recruited 16 male subjects (ages 19 to 24) undertaking aerobic exercise (>4 hours per week) to aid in investigating the relationship between magnesium supplementation and systolic blood pressure at rest and post-exercise and its overall effect on performance. Results indicated that oral magnesium supplementation significantly reduced resting and post exercise blood pressure.15
Sleep for recovery
At the end of the day, what really impacts exercise recovery is the training status of an individual. The right supplements may aid in exercise recovery but can never make up for bad habits in nutrition, training and sleep. Sleep is one of the most overlooked recovery and performance tools. Athletes and active consumers struggle to give their bodies the rest it needs to support optimal performance.
Sleep is often suggested to be the single-best recovery strategy available to athletes and active consumers. The body recovers and restores during sleep. All the nutritional foods, supplements and ingredients consumed during the day have time to settle in and get to work while the body rests at night. Shortchanging sleep leads to losing out on the cognitive, emotional and physical benefits it can provide.
According to the National Institutes of Health (NIH) National Institute of Neurological Disorders and Stroke, there are five basic sleep stages. Stage 1 is the changeover from wakefulness to sleep. Stage 2 is a period of light sleep before entering a deeper sleep. Stage 3 is where the magic happens in recovery. Stage 3 is non-rapid eye movement (REM) deep sleep marked by a slowed heartbeat, slowed breathing levels and full muscle relaxation. During this muscle relaxation stage 3 sleep, growth hormones rise, helping to grow and repair tissues and muscles. Additionally, inadequate sleep may alter cytokines (signaling molecules) involved in skeletal muscle recovery. One study performed on 11 elite cyclists demonstrated that inadequate sleep led to a decreased maximal jump performance and impaired joint coordination and reaction time, all of which increase risk of injury.16
It is imperative that athletes don’t shortchange sleep and the benefits and mechanisms it has to offer. Melatonin is an endogenous hormone used to signal sleep and may be a beneficial ingredient for athletes who have trouble falling or staying asleep. CBD is another ingredient continually on the rise for its touted benefits for exercise recovery and promoting restful sleep. CBD can be taken in the form of a capsule, tincture, topical or special sleep formula, among other delivery methods. Studies on CBD and sleep show great promise, but more research is needed to understand its full potential and impact, especially on exercise and athletes.17
Recovery is needed to replenish nutrients lost, restore fuel and so much more. Natural ingredients can supplement exercise recovery, but it’s important for athletes and active consumers to develop proper nutrition, training and sleep habits to experience maximum recovery.
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9 Takahashi M et al. “Effects of curcumin supplementation on exercise-induced oxidative stress in humans.” Int J Sports Med. 2014 Jun;35(6):469-75.
10 Mallard A et al. “Curcumin Improves Delayed Onset Muscle Soreness and Postexercise Lactate Accumulation.” Journal of Dietary Supplements. DOI: 10.1080/19390211.2020.1796885.
11 Bell P et al. “Montmorency cherries reduce the oxidative stress and inflammatory responses to repeated days high-intensity stochastic cycling.” Nutrients. 2014 Feb 21;6(2):829-43.
12 Smith G et al. “Dietary omega-3 fatty acid supplementation increases the rate of muscle protein synthesis in older adults: a randomized controlled trial.” Am J Clin Nutr. 2011 Feb;93(2):402-12.
13 West D et al. “Whey Protein Supplementation Enhances Whole Body Protein Metabolism and Performance Recovery after Resistance Exercise: A Double-Blind Crossover Study.” Nutrients. 2017, 9(7), 735.
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17 Kasper A et al. “High Prevalence of Cannabidiol Use Within Male Professional Rugby Union and League Players: A Quest for Pain Relief and Enhanced Recovery.” International Journal of Sports Nutrition and Exercise Metabolism. 2020;30(5), 315-322.