Resistance exercise

Background: Caffeine is widely recognized as a potent ergogenic aid commonly used to enhance exercise performance and recovery. However, individual responses to caffeine can vary significantly, a variability that might be explained by genetic differences.Aim: This study aimed to investigate the influence of the CYP1A2 rs762551 SNP on the effects of caffeine (CAF) consumption on growth hormone (GH) and testosterone (TS) levels response to resistance exercise (RE) in male athletes.Materials and Methods: Thirty resistance-trained men (mean age 21.72±4.06 years, weight 77.31±14.07 kg, height 179.31±5.08 cm) participated in a randomized, double-blind, placebo-controlled, crossover study. They consumed either CAF (6 mg/kg) or placebo (PL; 6 mg/kg maltodextrin) one hour before performing a RE protocol including three sets with 85% of 1RM and two-minute rest. CYP1A2 genotyping categorized participants as AA homozygous ("fast" metabolizers) or AC heterozygous ("slow" metabolizers). GH and TS levels were measured by ELISA methods.Results: Repeated measures ANOVA showed significant differences in GH levels across time (F=10.94, P=0.000), with significant time-group (F=4.3, P=0.019) and time-genotype-group interactions (F=3.83, P=0.024). One-way ANOVA indicated significant differences in GH levels between CAF and PL conditions in AA individuals, but not in AC/CC genotypes. For testosterone, significant effects of time (F=14.88, P=0.000) and time-group interaction (F=3.197, P=0.045) were observed. Post-RE CAF supplementation significantly increased serum GH and TS levels in AA individuals compared to PL. Both CAF and PL groups showed increased serum hormone concentrations post-exercise.Conclusion: In conclusion, the study demonstrated that caffeine consumption significantly increased serum levels of growth hormone and testosterone in individuals with the AA genotype of the CYP1A2 rs762551 SNP. These findings suggest that genetic variations play a role in the hormonal response to caffeine, which may have implications for exercise performance and recovery strategies.

Purpose: With the aging population facing an increased risk of ocular conditions such as glaucoma, age-related macular degeneration (AMD), and diabetic retinopathy, finding non-invasive methods to support eye health is essential. This meta-analysis aims to compare the effects of aerobic, isometric, and resistance exercises on visual acuity and overall eye health in the elderly, seeking to identify which type of exercise may be most beneficial for maintaining or improving eye health. Method: A systematic review and meta-analysis were conducted following standard guidelines. Electronic databases, including PubMed, Scopus, and Web of Science, were searched for relevant studies published between 2000 and 2023. The search included terms related to aerobic, isometric, and resistance exercises, visual acuity, intraocular pressure (IOP), retinal health, and elderly populations. Studies were screened and selected based on predefined inclusion criteria, focusing on research involving elderly participants and outcomes related to eye health. Results: A total of 15 studies met the inclusion criteria, encompassing 1,200 participants with a mean age of 68 years. The meta-analysis revealed that aerobic exercise significantly reduced intraocular pressure (mean difference = -2.5 mmHg, 95% CI: -3.2 to -1.8, p < 0.001) and improved retinal health markers (effect size = 0.35, 95% CI: 0.20 to 0.50, p < 0.01). Resistance exercise was associated with enhanced visual acuity (effect size = 0.28, 95% CI: 0.15 to 0.41, p < 0.01) and a reduction in the progression of AMD (relative risk = 0.70, 95% CI: 0.50 to 0.90, p < 0.05). Isometric exercises showed minimal impact on eye health compared to the other exercise types (effect size = 0.05, 95% CI: -0.10 to 0.20, p = 0.40). Conclusion: This meta-analysis supports the idea that aerobic and resistance exercises can protect visual acuity and overall eye health in the elderly, likely due to improved blood circulation, reduced oxidative stress, and enhanced retinal function. In contrast, isometric exercises showed minimal benefits, potentially due to their limited impact on systemic circulation. These findings suggest the importance of specific physical activities for mitigating age-related ocular disease risks, with implications for clinical and public health guidelines aimed at preventing visual decline in aging populations.