Caffeine during High-Intensity Whole-Body Exercise: An Integrative Approach beyond the Central Nervous System

Abstract

Caffeine is one of the most consumed ergogenic aids around the world. Many studies support the ergogenic effect of caffeine over a large spectrum of exercise types. While the stimulatory effect of caffeine on the central nervous system is the well-accepted mechanism explaining improvements in exercise performance during high-intensity whole-body exercise, in which other physiological systems such as pulmonary, cardiovascular, and muscular systems are maximally activated, a direct effect of caffeine on such systems cannot be ignored. A better understanding of the effects of caffeine on multiple physiological systems during high-intensity whole-body exercise might help to expand its use in different sporting contexts (e.g., competitions in different environments, such as altitude) or even assist the treatment of some diseases (e.g., chronic obstructive pulmonary disease). In the present narrative review, we explore the potential effects of caffeine on the pulmonary, cardiovascular, and muscular systems, and describe how such alterations may interact and thus contribute to the ergogenic effects of caffeine during high-intensity whole-body exercise. This integrative approach provides insights regarding how caffeine influences endurance performance and may drive further studies exploring its mechanisms of action in a broader perspective.

Caffeine Improves Simulated 800-m Run Performance without Affecting Severe Exercise-Induced Arterial Hypoxemia

“…Prior investigations have documented that caffeine intake (5-6 mg of caffeine per kg of body weight) led to an elevation in calcium release from the sarcoplasmic reticulum (19), motor-unit recruitment (16), and muscle fiber conduction velocity (15), all of which can increase muscle contraction. Given that caffeine ingestion may increase the force of contraction in fatigued, but not in fresh, muscles as proposed in a recent review article (13), it is plausible that caffeine ingestion might have amplified contractions of fast-twitch muscle fibers during the latter phase of the exercise, thereby enabling participants to sustain the run for an extended period. Alternatively, caffeine may have exerted a mitigating effect on the afferent signaling from the working muscles to the central nervous system, thereby reducing the inhibitory influence of locomotor muscle fatigue on the central motor drive, as previously hypothesized (13).…”

Caffeine Increases Endurance Performance via Changes in Neural and Muscular Determinants of Performance Fatigability

“…There is also some evidence to suggest that CAF acts as a powerful vasoconstrictor of inactive regions (52). This may assist in blood flow redistribution to active muscles, ultimately improving muscle O 2 delivery and reducing intramuscular metabolic perturbation (15). In addition, a reduction in muscle recruitment secondary to O 2 -sensitive signals residing within the own brain cannot be disregarded, as a lower muscle recruitment during high-intensity, whole-body exercise has been reported when arterial O 2 content is saturated (SpO 2 = 100%) via breathing a hyperoxia gas mixture (20).…”

“…Of particular relevance is the ergogenic effect of CAF during high-intensity, whole-body exercise (1,2,9,15). Highintensity, whole-body exercise demands the engagement of a large muscle mass and a significant interaction between various physiological systems (16); thus, determination of the mechanisms behind the ergogenic effects of CAF is a challenge.…”

Effects of caffeine on neurobehavior in different age groups

“…This may result in symptoms such as headaches, vertigo, and poor fine motor coordination. As shown in Figure 2, coffee intake can also have a noticeable effect on endurance in adults [7]. As a result, the regulation of human endurance by regulating the amount of caffeine in the human body enables it to become a comprehensive method that goes beyond the central nervous system.…”