Nicotine supplementation enhances simulated game performance of archery athletes

Effects of caffeinated chewing gum-induced sympathetic activation and diuretic effect on the rapid rate of weight loss in bodybuilders: a double-blind crossover study

BACKGROUND

The purpose of this study was to investigate effects of caffeinated chewing gum-induced sympathetic activation and diuretic effect on the rapid rate of weight loss in bodybuilders.

METHODS

Fourteen current elite natural bodybuilding athletes (age: 26 ± 7 years old; BMI: 26.9 ± 7.1 kg/m2; muscle mass: 40.4 ± 7.1 kg; %body fat: 15.5 ± 4.4%) were included as participants. After confirming the specific gravity of the urine, the participants chewing either caffeinate Gum containing 3 mg/kg of caffeine (CAF trial) or placebo gum without containing caffeine (PL trial) for 10 min, with a randomized, double-blind, cross-over design. Following a 15-minute period of rest, the participants undergo a weight reduction process by engaging in cycling on a bicycle with an adjustable resistance level. The cycling is performed until the participant has experienced a dehydration state, resulting in a weight reduction of 2% of their initial body weight. Record time, heart rate, heart rate variability (HRV) urination volume and energy expenditure from exercise to completion of dehydration.

RESULTS

The urination volume (P = 0.040) and sympathetic activation were significantly higher in the CAF trial than in the PL trial during dehydration exercise (P < 0.05). Time to dehydration (P = 0.024) and the rating of perceived exertion (RPE) score during exercise were significantly lower in the CAF trial than in the PL trial. There were no significant differences in heart rate and energy expenditure during dehydration exercise between the two trials (P < 0.05).

CONCLUSIONS

This study found that chewing caffeinated gum increased sympathetic nerve activity and accelerated dehydration in bodybuilders.

TRIAL REGISTRATION

This study was registered in ClinicalTrials.gov (Date: 04/08/2024; ID "NCT06431035"; https://register.

CLINICALTRIALS

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Posttraining Dry Cupping Treatment Elevates Heart Rate Variability in Taekwondo Athletes

ABSTRACT

Elite taekwondo (TKD) athletes require physical strength and mastery of complex techniques to excel in a highly competitive environment. This study aimed to investigate the effects of dry cupping posttraining on heart rate variability (HRV) and recovery in TKD athletes. Fourteen male TKD athletes participated in a crossover study and were randomly assigned to either a dry cupping (Group CUP) or a placebo group without cupping (Group PLA) after completing a standardized TKD-specific training program. A 28-day washout period was implemented between the two treatments to minimize potential carryover effects. HRV and rated perceived exertion (RPE) were evaluated at three-time points: before training (Pre), immediately after training (Post), and 30 min after rest or dry cupping (Post30) in both groups. The results indicated that heart rate (HR) at Post and Post30 was significantly higher than at Pre in both groups. Low frequency (LF) and the LF/high frequency (HF) ratio at Post were significantly elevated compared to Pre in both groups. However, at Post30, these values remained significantly higher in Group PLA but not in Group CUP. HF at Post was significantly reduced compared to Pre in both groups, but at Post30, this reduction persisted only in Group PLA and not in Group CUP. Significant differences in the levels of LF, HF, and the LF/HF ratio were observed between Group PLA and Group CUP at Post30. The CUP group also showed significantly lower RPE compared to the PLA group at Post30. In conclusion, dry cupping treatment after TKD training significantly improved HRV parameters and reduced perceived fatigue, suggesting its potential as an effective method for enhancing recovery in TKD athletes.

Acute Effects of Nicotine on Physiological Responses and Sport Performance in Healthy Baseball Players

There is interest in whether nicotine could enhance attention in sporting performance, but evidence on the acute effect of nicotine on physical response and sports performance in baseball players remains scant. This was an observational study to examine whether nicotine gum chewed before exercise could provide acute effects on physiological responses and sport performance. Accordingly, heart rate variability (HRV), saliva cotinine concentration and α-amylase activity, cognitive function, muscle strength, and baseball-hitting performance were measured. Thirteen healthy male non-smoker baseball players were recruited. Conducting two sequences with 7-day intervals, they chewed nicotine gum (nicotine group) or flavor-matched placebo gum (placebo group) for 30 min. HRV and saliva analyses were conducted before gum consumption (S1), after gum consumption (S2), and after test completion (S3). Cognitive, muscle strength, and baseball-hitting performance tests were performed after nicotine or placebo gum chewing. The outcomes of all assessed variables were compared within and between the groups. Significant changes in HRV, α-amylase, testosterone, and cortisol were observed in the nicotine group at S2 and S3 (p < 0.05). Compared with the placebo group, the nicotine group exhibited enhanced motor reaction times, grooved pegboard test (GPT) results on cognitive function, and baseball-hitting performance, and small effect sizes were noted (d = 0.47, 0.46 and 0.41, respectively). Nicotine could induce changes in endocrine and sympathetic nerve activity and enhance cognitive function and baseball-hitting performance. However, no increase in muscle strength was observed after nicotine intake.