Abstract
Background: Caffeine ingestion improves athletic performance, but impairs sleep quality. We aimed to analyze the effect of caffeine intake on 800-m running performance, sleep quality (SQ), and nocturnal cardiac autonomic activity (CAA) in trained runners. Methods: Fifteen male middle-distance runners participated in the study (aged 23.7 ± 8.2 years). In a randomized and comparative crossover study design, the athletes ingested a placebo (PL) or caffeine supplement (CAF; 6 mg∙kg−1) one hour before an 800-m running time-trial test in the evening. During the night, CAA and SQ were assessed using actigraphy and a sleep questionnaire. A second 800-m running test was performed 24 h after the first. Time, heart rate, rating of perceived exertion, and blood lactate concentration were analyzed for each running test. Results: No significant differences in CAA and performance variables were found between the two conditions. However, CAF impaired sleep efficiency (p = 0.003), actual wake time (p = 0.001), and the number of awakenings (p = 0.005), as measured by actigraphy. Also, CAF impaired the questionnaire variables of SQ (p = 0.005), calm sleep (p = 0.005), ease of falling asleep (p = 0.003), and feeling refreshed after waking (p = 0.006). Conclusion: The supplementation with caffeine (6 mg∙kg−1) did not improve the 800-m running performance, but did impair the SQ of trained runners.
Highlights
Scientists and coaches are continually looking for techniques to develop more effective and efficient methods to improve exercise performance [1]
Caffeine is frequently used in sport as an ergogenic aid to improve athletic performance and endurance [3]
A randomized and comparative crossover study was conducted to test the effects of caffeine intake or placebo before an 800-m running time trial on actigraphic sleep quality (SQ), the subjective quality of sleep, nocturnal autonomous cardiac activity, countermovement jump (CMJ), and the 800-m performance of athletes at international and national levels
Summary
Scientists and coaches are continually looking for techniques to develop more effective and efficient methods to improve exercise performance [1]. One of the popular methods commonly used by athletes to maximize their physical performance is the intake of legal ergogenic aids [2]. Caffeine is a xanthine alkaloid that increases central nervous activity by the blockade of central and peripheral adenosine receptors [5] This stimulant action produces a greater recruitment of motor units [6], improves the Na+ –K+ pump response [7], and increases the rate of calcium release from the sarcoplasmic reticulum [8] and the mobilization of free fatty acids [9]. Caffeine ingestion improves athletic performance, but impairs sleep quality. We aimed to analyze the effect of caffeine intake on 800-m running performance, sleep quality (SQ), and nocturnal cardiac autonomic activity (CAA) in trained runners.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have