Before writing about the latest cutting-edge supplements that turn out to be effective or have enough evidence to speed up muscle recovery processes in our athlete (we’ll leave them for a third of the article). We will talk about a key factor that most of the time is overlooked. This is about the state of (eu) hydration, so loved by some and so hated by others.
We know how recovery is also influenced by the amount of exercise-induced muscle damage (EIMD) that occurs when the structural and functional properties of skeletal muscle are altered, especially when performing multiple sessions or numerous competitive events in a short period of time. .
Dehydration mainly refers to the loss of intracellular fluid. Since sweat is hypotonic relative to blood, sweat losses elicited plasma osmolality and decreased blood volume, leading to hyperosmotic and hypovolemic stressors.
EIMD is strongly associated with loss of strength, perception of pain, and elevations of circulating muscle enzymes or proteins (eg, CK, myoglobin…).
Although the optimal stimulus to maximize performance adaptations and optimize recovery is unknown. The proposed mechanisms could explain the decreased performance associated with decreased plasma volume, cardiac filling, and stroke volume. These factors once cause a reduction in blood flow which ends up altering muscle metabolism and hinders correct thermoregulation, especially in hot environments. All of these factors could intensify the EIMD and prolong recovery.
Although the precise role of acute dehydration in EIMD is unclear, rehydration plays an important role in recovery from exercise. Adequate hydration can help alleviate all of these potential processes that can influence EIMD, such as the independent and combined effects of osmotic stress, cellular inflammation (muscle swelling and accumulation of metabolites), and hyperthermia.
At higher levels of dehydration (4-5% loss of body mass), increased blood viscosity increases ROS production through increased vascular tension and the stiffness of red blood cells.
Increased ROS generation in skeletal muscle can damage the sarcolemma, cytoskeleton, and DNA, as well as the contractile units of skeletal muscle, making it difficult for the muscle to contract. It is important to note that the production of ROS is necessary to produce adaptations to stressors such as exercise itself, the problem comes from the excess (like everything in this life) of these free radicals and reactive oxygen species, that is when a maladaptive response.
Dehydration can mainly affect fast twitch fibers which are also preferentially damaged by eccentric exercise potentially creating an additive effect on muscle damage.
Regardless of hydration status, rodent models suggest that hyperthermia has a strong influence on skeletal muscle damage. Muscle temperatures that reach> 40 ° C (104 ° F) during intense exercise have been shown to increase passive tension. This also leads to more muscle damage.
A secondary mechanism is through proteases and phospholipases as these can impede calcium-mediated release of calcium in the sarcoplasmic reticulum, further challenging muscle contraction.
Some studies date as dehydrated athletes higher levels of blood biomarkers related to muscle damage and delayed recovery (aspartate aminotransferase, nitrogen, blood urea, LDH and CK) than the euhydrated groups.
In conclusion and knowing the limitations where the independent effects of exercise can cloud the interpretation of the results, since this alone can cause a greater production of heat, fluid changes and ROS production.
Although there are major methodological problems in human studies, dehydration may increase the severity of muscle damage and prolong recovery, especially in combination with hyperthermia. Therefore, we would talk about staying hydrated can be one of the greatest ergogenic aids.
