Pseudoephedrine and circadian rhythm interaction on neuromuscular performance

Abstract

This study analyzed the effects of pseudoephedrine (PSE) provided at different time of day on neuromuscular performance, side effects, and violation of the current doping cut-off threshold [World Anti-Doping Agency (WADA)]. Nine resistance-trained males carried out bench press and full squat exercises against four incremental loads (25%, 50%, 75%, and 90% one repetition maximum [1RM]), in a randomized, double-blind, cross-over design. Participants ingested either 180 mg of PSE (supra-therapeutic dose) or placebo in the morning (7:00 h; AM(PLAC) and AM(PSE)) and in the afternoon (17:00 h; PM(PLAC) and PM(PSE)). PSE enhanced muscle contraction velocity against 25% and 50% 1RM loads, only when it was ingested in the mornings, and only in the full squat exercise (4.4-8.7%; P < 0.05). PSE ingestion raised urine and plasma PSE concentrations (P < 0.05) regardless of time of day; however, cathine only increased in the urine samples. PSE ingestion resulted in positive tests occurring in 11% of samples, and it rose some adverse side effects such us tachycardia and heart palpitations. Ingestion of a single dose of 180 mg of PSE results in enhanced lower body muscle contraction velocity against low and moderate loads only in the mornings. These mild performance improvements are accompanied by undesirable side effects and an 11% risk of surpassing the doping threshold.

Use of nutritional supplements and ergogenic aids in professional tennis players

“…Increasing prevalence of NtS and EA use among athletes has alerted health and sports authorities, since a non-negligible amount of NtS and EA are contaminated with harmful/banned substances (6). This could endanger athlete's health or cause competition ban if containing doping substances (7). Although the use of NtS and EA is generalized in all the spectrum of performance (i.e., from recreational to elite athletes), only a few EA (e.g., creatine, sodium bicarbonate, caffeine) have been demonstrated to result in enhanced sports performance (8).…”

Effects of pseudoephedrine on parameters affecting exercise performance: a meta-analysis

“…However, this was accompanied by a larger effect on increasing HR. A recent study looking at neuromuscular performance effects using these more effective higher PSE doses (180 mg) noted adverse side effects such as tachycardia and heart palpitations 24 h after exercise [ 18 ]. This suggests it will be increasingly difficult to get ethical approval to test the most effective doses of PSE, making it important to carry out the most complete analysis of the studies that have already been performed.…”

“…Studies must have used PSE as the only substance in the intervention, and they were excluded if the substance was not specifically being investigated for its ergogenic effect [ 17 ]. Also excluded were studies investigating the effects of PSE on strength and neuromuscular coordination because data were incomparable with included articles [ 10 , 18 ]. Studies that investigated other substances were included if participants were not administered both substances simultaneously [ 7 , 12 , 19 ].…”

Muscle contraction velocity, strength and power output changes following different degrees of hypohydration in competitive olympic combat sports

“…Our neuromuscular bench press testing is highly normalized and has high reproducibility [ 23 ] and sensibility [ 34 – 36 ]. However, neuromuscular function is influenced by circadian rhythm [ 34 , 37 ].…”

“…However, neuromuscular function is influenced by circadian rhythm [ 34 , 37 ]. We have reported 5.6–8.6 % reductions in bench press muscle power in the morning (8:00 h) in comparison to the afternoon (i.e., 18:00 h; [ 34 , 36 , 37 ]). Thus, the lack of increase in bench press muscle power in the group that recovered 1.2 % of their body mass (i.e., HYP) could be partially due to the fact that the test after rehydration (POST) was conducted in the morning (between 8:00 h and 10:00 h), while the hypohydrated test (PRE) was conducted in the evening (between 16:00 h and 19:00 h).…”