Effects of Caffeine Intake on Cardiopulmonary Variables and QT Interval after a Moderate-Intensity Aerobic Exercise in Healthy Adults: A Randomized Controlled Trial

Caffeine is considered a widely consumed natural and legal psychoactive stimulant with several effects on the body. The present study attempted to investigate the effects of caffeine consumed before and after a physical exercise on cardiovascular and cardiorespiratory functions in healthy adults. 36 healthy adult males were recruited and randomly allocated to one of the three (3) groups: group I (exercise without caffeine consumption), group II (caffeine beverage intake before exercise), and group III (caffeine beverage intake immediately after exercise). The heart rate (HR), QTc interval, blood pressure (BP), respiratory rate (RR), oxygen consumption (VO₂), and carbon dioxide emission (VCO₂) were measured at 0, 5, 10, and 15 min after the exercise. We observed a significant difference in all measured outcomes during the different recovery times in all the groups ( p < 0.05 ). HR, RR, SBP, VO2, and VCO2 gradually decreased with time, DBP contrarily increased with time, and the QTc showed an irregular pattern. We can affirm that ingestion of caffeine before and after moderate aerobic exercise slows down the parasympathetic stimulation, heart rate recovery, and the recovery of HR and QTc with no major effects on BP, RR, VO₂, and VCO₂ in healthy adult men.

Caffeine Consumption Influences Lidocaine Action via Pain-Related Voltage-Gated Sodium Channels: An In Vivo Animal Study

Several factors might influence the duration and efficiency of local anesthesia. This study investigates the effect of habitual caffeine intake on lidocaine action and explores the potential involvement of voltage-gated sodium channels in the interaction effect. Wistar rats were divided into four groups: (i) control (Ctrl), (ii) lidocaine intraplantar injection (LIDO), (iii) habitual caffeine intake (CAF), and (iv) lidocaine intraplantar injection and habitual caffeine intake (LIDO + CAF). Behavioral assessments, consisting of a paw pressure test for mechanical pressure sensation and a paw withdrawal latency test for thermal pain sensation, were performed at 0, 30, 60, and 90 minutes following lidocaine injection and after 10, 11, and 12 weeks of CAF intake. Pressure sensation was significantly reduced in the LIDO + CAF group compared with the control group. Moreover, the LIDO + CAF group exhibited reduced sensation compared to LIDO alone group. The LIDO + CAF combination exerted a synergistic effect at 30 and 60 minutes compared with the control. This synergistic effect was noted at 60 minutes (11 weeks of CAF intake) and at 30 minutes (12 weeks of CAF intake) compared with LIDO alone. Augmented thermal pain-relieving effects were observed in the LIDO + CAF group at all weeks compared to the control group and at 10 weeks compared to LIDO alone group. The molecular analysis of dorsal root ganglia suggested that CAF upregulated the mRNA expression of the Nav1.3, Nav1.7, and Nav1.8 sodium channel subtypes. Chronic caffeine consumption potentiates the local anesthetic action of lidocaine in an experimental animal model through mechanisms that involve the upregulation of voltage-gated sodium channels in the dorsal root ganglia.

Caffeine Induces G0/G1 Cell Cycle Arrest and Inhibits Migration through Integrin αv, β3, and FAK/Akt/c-Myc Signaling Pathway

Lung cancer is recognized as a major cause of mortality worldwide owing to its metastatic activity. Given the lack of solid information regarding the possible effects of caffeine, one of the most consumed natural psychoactive substances, on molecular signaling pathways implicated in the aggressive behavior of lung cancer, our study aimed to evaluate the effect and mechanism of caffeine on metastasis-related mechanisms. The results revealed that caffeine treatment at concentrations of 0–500 µM caused no direct cytotoxic effects on NCI-H23 cells. Treatment of cells with caffeine showed good potential to inhibit cell proliferation at 48 h and induced significant cell cycle arrest at the G0/G1 phase. Concerning metastasis, caffeine was shown to reduce filopodia formation, inhibit migration and invasion capability, and reduce the ability of cancer cells to survive and grow in an anchorage-independent manner. Moreover, caffeine could attenuate the formation of 3D tumor spheroids in cancer stem cell (CSC)-enriched populations. With regard to mechanisms, we found that caffeine significantly altered the integrin pattern of the treated cells and caused the downregulation of metastasis-associated integrins, namely, integrins αv and β3. Subsequently, the downstream signals, including protein signaling and transcription factors, namely, phosphorylated focal adhesion kinase (p-FAK), phosphorylated protein kinase B (p-Akt), cell division cycle 42 (Cdc42), and c-Myc, were significantly decreased in caffeine-exposed cells. Taken together, our novel data on caffeine-inhibiting mechanism in relation to metastasis in lung cancer could provide insights into the impact of caffeine intake on human diseases and conditions.

The Association between Coffee and Caffeine Consumption and Renal Function: Insight from Individual-Level Data, Mendelian Randomization, and Meta-Analysis

IntroductionBy applying on two-sample Mendelian randomization and systematic review and meta-analysis we investigated the association between caffeine and coffee intake with prevalent CKD and markers of renal function.Material and methodsFor the individual data analysis we analysed the NHANES data on renal function markers and caffeine intake. MR was implemented by using summary-level data from the largest ever GWAS conducted on coffee intake (N=91,462) and kidney function.ResultsFinally, we included the data of 18,436 participants, 6.9% had prevalent CKD (based on eGFR). Caffeine intake for general population was 131.1±1.1 mg. The percentage of participants with CKD, by caffeine quartile was 16.6% in the first (lowest) quartile, 13.9% in the second, 12.2% in the third and 11.0% in the top quartile (p<0.001). After adjustment, for increasing quartiles for caffeine consumption, mean urine albumin, albumin-creatinine ratio and estimated glomerular filtration rate (GFR) did not change significantly (p>0.234). In fully adjusted logistic regression models, there was no significant difference in chances of CKD prevalence (p-trend=0.745). In the same line, results of MR showed no impact of coffee intake on CKD (IVW=β: -0.0191, SE: 0.069, p=0.781), on eGFR (overall= IVW= β: -0.0005, SE: 0.005, p=0.926) both in diabetic (IVW= β: -0.006, SE: 0.009, p=0.478), and non-diabetic patients (IVW= β: -6.772, SE: 0.006, p=0.991). Results from the meta-analysis indicted that coffee consumption was not significantly associated with CKD (OR: 0.85, 95%CI 0.71-1.02, p=0.090, n=6 studies, I2=0.32).ConclusionsBy implementing on different strategies, we have highlighted no significant association between coffee consumption with renal function and chance of CKD.

Caffeine Prevalence, Daily Consumption, and Factors Associated with Use among Active Duty United States Military Personnel

Background: Although representative data on caffeine intake in Americans are available these data do not include US service members (SMs). The few previous investigations in military personnel largely involve convenience samples. This cross-sectional study examined prevalence of caffeine use, daily consumption, and factors associated with use among United States active duty military service members (SMs). Methods: A stratified random sample of 200,000 SMs were asked to complete a questionnaire on their personal characteristics and consumption of caffeinated products. Eighteen percent (n=26,680) of successfully contacted SMs (n=146,365) completed the questionnaire. Results: Overall, 87% reported consuming caffeinated products ≥1 time/week. Mean ± standard error per-capita consumption (all participants) was 218±2 and 167±3 mg/day for men and women, respectively. Caffeine consumers ingested 243±2 mg/day (251±2 mg/day men, 195±3 mg/day women). On a body-weight basis, men and women consumed respectively similar caffeine amounts (2.93 vs 2.85 mg/day/kg; p=0.12). Among individual caffeinated products, coffee had the highest prevalence (68%), followed by sodas (42%), teas (29%), energy drinks (29%) and gums/candy/medications (4%). In multivariable logistic regression, characteristics independently associated with higher use prevalence (≥1 time/week) included female gender, older age, white race/ethnicity, higher body mass index, tobacco use or former use, greater alcohol intake, and higher enlisted or officer rank. Conclusion: Compared to National Health and Nutrition Survey Examination data, daily consumption (mg/day) by SMs was higher, perhaps reflecting higher mental and physical occupational demands on SMs.

Overview of the Effect of Complementary Medicine on Treating or Mitigating the Risk of Endometriosis

Objective Endometriosis is a hormone-dependent chronic inflammatory disease with symptoms such as pelvic pain, which affect the physical, emotional, and social health of women in reproductive age. The current overview article aims to explore the effect of complementary medicine on the treatment or in mitigating the risk of endometriosis. Methods This is an overview article done in Iran. Two separate researchers systematically searched 3 databases (Medline, Scopus, and Cochrane Central Register Trials) until September 2020. The methodological quality of each study was assessed using the assessment of multiple systematic reviews (AMSTAR) tool. Results The results of two reviews suggested that physical activity, tobacco smoking, diet, coffee and caffeine intake had no effect on mitigating the risk of endometriosis or improving its treatment, but acupuncture successfully reduced pain and related marker (serum CA-125) levels. Conclusion As endometriosis is an annoying disease with many complications and is hard to diagnose and treat, related studies in complementary medicine can help patients with endometriosis. Based on the relevant literature review, among the complementary medicine available for the treatment or to mitigate the risk of endometriosis, only acupuncture seems to alleviate the pain of endometriosis.

Caffeine increases performance and leads to a cardioprotective effect during intense exercise in cyclists

The present study was designed to investigate the effects of different caffeine dietary strategies to compare the impact on athletic performance and cardiac autonomic response. The order of the supplementation was randomly assigned: placebo(4-day)-placebo(acute)/PP, placebo(4-day)-caffeine(acute)/PC and caffeine(4-day)-caffeine(acute)/CC. Fourteen male recreationally-trained cyclists ingested capsules containing either placebo or caffeine (6 mg kg−1) for 4 days. On day 5 (acute), capsules containing placebo or caffeine (6 mg kg−1) were ingested 60 min before completing a 16 km time-trial (simulated cycling). CC and PC showed improvements in time (CC vs PP, Δ − 39.3 s and PC vs PP, Δ − 43.4 s; P = 0.00; ƞ2 = 0.33) and in output power (CC vs PP, Δ 5.55 w and PC vs PP, Δ 6.17 w; P = 0.00; ƞ2 = 0.30). At the final of the time-trial, CC and PC exhibited greater parasympathetic modulation (vagal tone) when compared to the PP condition (P < 0.00; ƞ2 = 0.92). Our study provided evidence that acute caffeine intake (6 mg∙kg−1) increased performance (time-trial) and demonstrated a relevant cardioprotective effect, through increased vagal tone.

Motivations for Caffeine Consumption in New Zealand Tertiary Students

Caffeine-related health incidents in New Zealand have escalated over the last two decades. In order to reduce the risk of substance-related harm, it is important to understand the consumers’ motivations for its use. This is especially true for tertiary students who are presumed to be at a higher risk due to seeking out caffeine’s well-known cognitive benefits as well as the targeted marketing of such products to young adults. This study examined the habits and motivations for caffeine consumption in tertiary students in New Zealand. A previously validated caffeine consumption-habits (CaffCo) questionnaire was administered online to 317 tertiary students (n = 169 females), aged ≥16 years. Of the 99.1% of participants who regularly consumed caffeine, coffee (76.3%) tea (71.6%) and chocolate (81.7%) consumption were the most prevalent. Motivations for caffeinated-product consumption differed according to caffeine source. Tea was consumed for the warmth and taste, coffee was consumed to stay awake and for warmth, and chocolate, for the taste and as a treat. Marketing was not identified by participants as influencing their consumption of caffeinated products. Knowledge of motivations for caffeine consumption may assist in identifying strategies to reduce caffeine intake in those New Zealand tertiary students who regularly consume amounts of caffeine that exceed safe level.

Predictors of CRC Stage at Diagnosis among Male and Female Adults Participating in a Prospective Cohort Study: Findings from Alberta’s Tomorrow Project

Colorectal cancer (CRC) is a leading cause of morbidity and mortality in Canada. CRC screening and other factors associated with early-stage disease can improve CRC treatment efficacy and survival. This study examined factors associated with CRC stage at diagnosis among male and female adults using data from a large prospective cohort study in Alberta, Canada. Baseline data were obtained from healthy adults aged 35–69 years participating in Alberta’s Tomorrow Project. Factors associated with CRC stage at diagnosis were evaluated using Partial Proportional Odds models. Analyses were stratified to examine sex-specific associations. A total of 267 participants (128 males and 139 females) developed CRC over the study period. Among participants, 43.0% of males and 43.2% of females were diagnosed with late-stage CRC. Social support, having children, and caffeine intake were predictors of CRC stage at diagnosis among males, while family history of CRC, pregnancy, hysterectomy, menopausal hormone therapy, lifetime number of Pap tests, and household physical activity were predictive of CRC stage at diagnosis among females. These findings highlight the importance of sex differences in susceptibility to advanced CRC diagnosis and can help inform targets for cancer prevention programs to effectively reduce advanced CRC and thus improve survival.