Massey Documents by Type
Permanent URI for this communityhttps://mro.massey.ac.nz/handle/10179/294
Browse
10 results
Search Results
Item The Effect of Pre-Exercise Caffeine and Glucose Ingestion on Endurance Capacity in Hypoxia: A Double-Blind Crossover Trial.(MDPI (Basel, Switzerland), 2024-10-25) Chiu C-H; Chen C-C; Ali A; Wu S-L; Wu C-L; Nieman DC; Schroder HThe impact of caffeine and glucose supplementation in a hypoxic environment on endurance exercise performance remains inconclusive. The current study examined the effect of pre-exercise carbohydrate and caffeine supplementation on endurance exercise performance in an acute hypoxic environment. Eight healthy active young males participated in this double-blind, within-subjects crossover study. Participants ingested the test drink 60 min before exercising at 50% Wmax for 90 min on a cycle ergometer (fatiguing preload); there followed an endurance performance test at 85% Wmax until exhaustion in a hypoxic chamber (~15%O2). Participants completed four experimental trials in a randomized order: caffeine (6 mg·kg-1; Caff), glucose (1 g·kg-1; CHO), caffeine (6 mg·kg-1) + glucose (1 g·kg-1; Caff-CHO), and taste- and color-matched placebo with no caffeine or CHO (PLA). Blood samples were collected during fasting, pre-exercise, every 30 min throughout the exercise, and immediately after exhaustion. The caffeine and glucose trials significantly enhanced endurance capacity in hypoxic conditions by Caff, 44% (68.8-31.5%, 95% confidence interval), CHO, 31% (44.7-15.6%), and Caff-CHO, 46% (79.1-13.2%). Plasma-free fatty-acid and glycerol concentrations were higher in Caff and PLA than in CHO and Caff-CHO (p < 0.05). The estimated rate of fat oxidation was higher in Caff and PLA than in CHO and Caff-CHO (p < 0.05). There were no significant differences in ratings of perceived exertion between trials. In conclusion, the ingestion of caffeine, glucose, or caffeine + glucose one hour before exercising in hypoxic conditions significantly improved 85% Wmax endurance performance after prolonged exercise.Item Secondary School Students and Caffeine: Consumption Habits, Motivations, and Experiences.(MDPI (Basel, Switzerland), 2023-02-17) Turner S; Ali A; Wham C; Rutherfurd-Markwick K; Cornelis M; Tauler PAdolescents may be particularly vulnerable to the effects of caffeine due to a lack of tolerance, their small size, changing brain physiology, and increasing independence. Concerns about adolescent caffeine consumption relate to potentially serious physiological and psychological effects following consumption. Motivations driving caffeine intake are not well understood among adolescents but are important to understand to reduce harmful behavioural patterns. This study explored caffeine consumption habits (sources, amount, frequency) of New Zealand adolescents; and factors motivating caffeine consumption and avoidance. The previously validated caffeine consumption habits questionnaire (CaffCo) was completed by 216 participants (15-18 years), with most (94.9%) consuming at least one caffeinated product daily. Chocolate, coffee, tea, and kola drinks were the most consumed sources. The median caffeine intake was 68 mg·day-1. Gender (boy) and being employed influenced the source, but not the quantity of caffeine consumed. One-fifth (21.2%) of adolescents consumed more than the recommended European Food Safety Authority (EFSA) safe level (3 mg·kg-1·day-1). Taste, energy, and temperature were the main motivators for consumption, and increased energy, excitement, restlessness, and sleep disturbances were reported effects following caffeine consumption. This study provides information on caffeinated product consumption among New Zealand adolescents, some of whom consumed caffeine above the EFSA safe level. Public health initiatives directed at adolescents may be important to reduce potential caffeine-related harm.Item Effects of carbohydrate and caffeine mouth rinsing on strength, muscular endurance and cognitive performance(Taylor and Francis Group on behalf of the International Society of Sports Nutrition, 2021-09-24) Karayigit R; Ali A; Rezaei S; Ersoz G; Lago-Rodriguez A; Domínguez R; Naderi ABACKGROUND: Carbohydrate (CHO) and caffeine (CAF) mouth rinsing have been shown to enhance endurance and sprint performance. However, the effects of CHO and CAF mouth rinsing on muscular and cognitive performance in comparison between male and female athletes are less well-established. The aim of this study was to examine the effect of CHO and CAF rinsing on squat and bench press 1 repetition maximum (1-RM) strength, 3 sets of 40% of 1-RM muscular endurance and cognitive performance in both male and female athletes. METHODS: Thirteen male and fourteen female resistance-trained participants completed four testing sessions following the rinsing of 25 ml of i) 6% of CHO (1.5 g); ii) 2% CAF (500 mg), iii) combined CHO and CAF (CHOCAF) solutions or iv) water (PLA) for 10 s. Heart rate (HR), felt arousal (FA), ratings of perceived exertion (RPE) and glucose (GLU) were recorded throughout the test protocol. RESULTS: There were no significant differences in squat and bench press 1-RM, HR, RPE and GLU (p > 0.05) for males and females, respectively. FA was significantly increased with CAF (p = 0.04, p = 0.01) and CHOCAF (p = 0.03, p = 0.01) condition in both males and females, respectively. Squat endurance performance in the first set was significantly increased with CHOCAF condition compared to PLA in both males (p = 0.01) and females (p = 0.02). Bench press endurance was similar for all conditions in both genders (p > 0.05). Cognitive performance was significantly increased with CHOCAF compared to PLA in males (p = 0.03) and females (p = 0.02). CONCLUSION: Combined CHO and CAF mouth rinsing significantly improved lower body muscular endurance and cognitive performance in both males and females.Item Motivations for Caffeine Consumption in New Zealand Tertiary Students(MDPI (Basel, Switzerland), 2021-11-25) Stachyshyn S; Wham C; Ali A; Knightbridge-Eager T; Rutherfurd-Markwick KCaffeine-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.Item Caffeine Consumption Habits of New Zealand Tertiary Students(MDPI (Basel, Switzerland), 2021-04-28) Stachyshyn S; Ali A; Wham C; Knightbridge-Eager T; Rutherfurd-Markwick KAdverse effects associated with excessive caffeine consumption combined with increasing numbers and availability of caffeine-containing products are causes for concern. Tertiary students may be at increased risk of consuming excessive amounts of caffeine due to seeking caffeinated products with well-known wakefulness effects and cognitive benefits. This study explored caffeine consumption habits of New Zealand tertiary students (317; ≥16-years) using a previously validated caffeine consumption habits (CaffCo) questionnaire. Most (99.1%) regularly consumed caffeinated products, especially chocolate, coffee and tea, with coffee, tea and energy drinks contributing most to total caffeine intake. Median estimated caffeine intake was 146.73 mg·day-1, or 2.25 mg·kgbw-1·day-1. Maximum and minimum intakes were 1988.14 mg·day-1 (23.51 mg·kgbw-1·day-1) and 0.07 mg·day-1 (0.02 mg·kgbw-1·day-1), respectively. One-third (34.4%) of caffeine consumers ingested caffeine above the adverse effect level (3 mg·kgbw-1·day-1) and 14.3% above the safe limit (400 mg·day-1). Most caffeine consumers (84.7%), reported experiencing at least one 'adverse symptom' post-caffeine consumption, of which 25.7% reported effects leading to distress or negatively impacting their life. Experiencing 'adverse symptoms' did not, however, curtail consumption in the majority of symptomatic participants (~77%). Public health initiatives directed at tertiary students may be important to reduce potential caffeine-related harm.Item Investigating the impact of genetic variability of CYP1A2, ADORA2A, and AHR on caffeine consumption and responses in New Zealanders : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Nutrition and Dietetics at Massey University, Albany, New Zealand(Massey University, 2019) Tennent, RebeccaBackground: Single nucleotide polymorphisms (SNPs), in three genes encoding for cytochrome P450 1A2 (CYP1A2; rs762551), adenosine A2A receptor (ADORA2A; rs5751876), and aryl-hydrocarbon receptor (AHR; rs4410790) are known to have links to caffeine consumption and metabolism, and its resultant effects. Exploration of the links between genetic profile and caffeine response will advance understanding of the impact of caffeine consumption on individuals with differing genetic profiles. Aim: To examine caffeine consumption patterns and post-consumption responses among New Zealand (NZ) individuals and how these differ with genetic variation of CYP1A2, ADORA2A, and AHR. Methods: Caffeine intake and post-consumption responses were assessed using a caffeine consumption habits questionnaire (CaffCo). Genetic data for the SNPs (CYP1A2, ADORA2A, AHR) was analysed using MassARRAY analysis on DNA extracted from saliva samples. CaffCo data was examined according to genotype for the three SNPs, which were then paired to consider links between genes. Results: 255 participants aged 15 years and over were included in the study. Half (49.4%) of all participants were “fast” metabolisers (CYP1A2 AA) and 10.2% “ultra-slow” metabolisers (CYP1A2 CC) of caffeine. Almost half of the participants carried ADORA2A CT (46.3%), followed by CC (29.0%), and TT (24.7%). Half (51.8%) of the participants carried AHR CT, followed by CC (30.6%), and TT (17.6%) genotypes. Overall, 14.1% of participants reported a caffeine intake >400 mg/day and 52.9% an intake of 80-400 mg/day. Carriers of the genotype ADORA2A TT consumed 65 mg/day less caffeine than carriers of the heterozygote genotype (ADORA2A CT; p= 0.034). No association was found with the other analysed SNPs. Conclusions: This novel research is the first in New Zealand to examine all three genes, identifying the genetic variation and caffeine consumption habits in this population. The data show an association between ADORA2A TT and decreased caffeine consumption in this population. Future studies are needed to assess caffeine response in relation to these three genes, to understand and develop appropriate strategies for informing genotype based advice on caffeine use.Item Secondary school students and caffeine : consumption habits, motivations and experiences : a thesis presented in partial fulfilment of the requirements of the degree of Master of Science in Nutrition and Dietetics(Massey University, 2019) Turner, SophieBackground: Recently, concerns have been raised about adolescent caffeine consumption due to its potentially serious physiological and psychological effects. Adolescents are vulnerable to the effects of caffeine due to their lack of habituation, smaller body mass and changing brain physiology. Increasing independence also exposes adolescents to new caffeinated products and provides greater freedom in their food and beverage decision making. The motivations that drive caffeine intake among adolescents are not well understood, but they are important in order to develop and implement public health strategies to reduce any harmful behavioural patterns and potential adverse effects. Therefore, it is important to determine which groups of adolescents if any are at increased at risk of caffeine-related harm, particularly as previous studies investigating adolescent caffeine intake are limited and outdated, especially within the New Zealand context. Aim: The aim of this study is to explore the caffeine consumption habits of New Zealand adolescents 15 to 18 years; the factors that motivate consumption and reasons for avoiding caffeine, over a range of caffeinated products. Methods: A previously validated caffeine consumption questionnaire (CaffCo) was administered to 217 participants 15 to 18 years via the online survey software Qualtrics. Results: Most (94.9%) New Zealand adolescents consume at least one caffeinated product daily, the most commonly consumed sources being chocolate, coffee, tea and kola drinks. The median daily caffeine intake was 68 mg.day⁻¹. Gender and employment status influence the pattern, but not overall amount of caffeine consumed. Energy drink consumption has risen dramatically over the past decade. One fifth (21.2%) of adolescents consume above the European Food Safety Authority (EFSA) safe level for caffeine intake of 3 mg.kg.⁻¹day⁻¹. Taste, energy and cold temperature were the main motivators for adolescent caffeine consumption. Increased energy, feeling excited, restlessness and sleep disturbances were frequently reported effects following caffeine consumption. Conclusions: This study gives an updated and more detailed view of caffeinated product consumption among New Zealand adolescents. A subset of adolescents consumes caffeine above the EFSA safe level and may benefit from public health strategies to reduce caffeine-related harm. Potential strategies may include education to improve “caffeine literacy” and improved regulations for labelling and advertising.Item The significance of CYP1A2 genotype on caffeine metabolism and exercise performance : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Human Nutrition at Massey University, Manawatu, New Zealand(Massey University, 2015) McGrath, Michelle ClareObjective: The objective of this study was to investigate whether a single nucleotide polymorphism (C to A transversion at position -163 downstream of the first transcribed nucleotide) in the enzyme that metabolizes caffeine (CYP1A2), would explain the variability seen in caffeine related responses in endurance exercise performance. In a double blind crossover trial, well trained male endurance athletes (n=11, mean VO2 max 69±4 mL.kg-1.min-1) ingested either caffeine (5 mg.kg-1) or a placebo 60 minutes prior to performing a lab based experimental protocol involving a two hour steady state cycle (70% VO2 max) followed by a 30 minute time trial to measure performance. The rate of caffeine metabolism over seven hours (inclusive of exercise period) was also determined by the HPLC analysis of plasma caffeine and its major metabolites, paraxanthine, theophylline and theobromine. Caffeine metabolism at rest over a similar seven hour period was also determined in the same manner. Results: Caffeine improved endurance performance by 7.1% (p=0.037) compared to a placebo. Caffeine also significantly elevated heart rate during the time trial (p=0.003); and RPE (p=0.010) and VO2 (p=0.047) during steady state exercise. There was no correlation between caffeine or paraxanthine concentrations at the start of the time trial and subsequent performance and the rate of caffeine metabolism was not significantly different between resting or exercising trials. Furthermore there was no significant interaction between caffeine treatment and CYP1A2 genotype on performance or any other variables measured. However there was a trend for carriers of the C allele showing faster metabolism than those homozygous A/A (p=0.097). Conclusions: Caffeine is ergogenic during endurance exercise, however individual responses were variable. In this study this variability could not be explained by CYP1A2 genotype. However the small sample size in this study especially when subjects were divided into genotype groups, makes drawing conclusions difficult.Item Effect of caffeine ingestion on aspects of endurance performance and cognition in CYP1A2 hetrozygous A/C male recreational athletes : a thesis presented in partial fulfilment for the requirements of a Master of Science in Sport and Exercise Science at Massey University, Albany, New Zealand(Massey University, 2016) Southward, KyleBackground: Globally, caffeine is the most widely accessible psychoactive drug and has been shown to improve endurance performance as well as aspects of cognition, mood and perceptual responses during exercise. However, the ergogenic effects of caffeine between individuals are variable, and the cause of this variability is unknown. The CYP1A2 gene is known to mediate caffeine metabolism and has been suggested as a contributor to the variability of the ergogenic effects of caffeine. Purpose: To investigate the effects of CYP1A2 genotype on exercise performance (10 km time trial), sleep, mood, cognition and perceptual responses following caffeine ingestion in adult male recreational athletes. Methods: 16 recreationally trained athletes (age = 26.9 ± 7.93 y; weight = 77.00 ± 9.04 kg) volunteered for this study. Participants completed a familiarisation session at least one week before the first trial and a saliva sample was collected for testing of the participants’ CYP1A2 genotype. Participants completed two trials one week apart in a randomised double-blind placebo-controlled cross-over design. Participants were asked to abstain from caffeine ingestion and keep a food diary for 24 h prior to the trial. Participants wore an actigraph, and completed a sleep diary and Leeds Sleep Evaluation Questionnaire (LSEQ) every day for the two week duration of the trials starting 3 days before the first trial and ending 3 days after the second trial. The main trial consisted of a set of pre- and post-ingestion measures which included leg power by vertical jump height (squat jump – SJ; countermovement jump – CMJ), leg strength by maximal voluntary concentric and eccentric contraction of the knee extensors (isokinetic dynamometer), perceptual (feeling scale – FS; felt arousal scale – FAS), mood (profile of mood states – POMS), cognition (digit vigilance – DV; Corsi blocks – CB; rapid visual information processing – RVIP) and heart rate. Pre- and post-ingestion urine, saliva and blood samples were also collected for analysis of caffeine metabolism and genotype. Following completion of pre-ingestion measures, participants consumed a capsule containing either anhydrous caffeine (6 mg∙kg-1) or placebo (maltodextrin) and were instructed to rest quietly for 50 min. Following post-ingestion measures, participants completed a 10-km time trial run. Perceptual measures (FS and FAS) including ratings of perceived exertion (RPE) were recorded every 2.5 km and heart rate was recorded every 1 km. A venous blood sample and saliva sample was collected at 5 km and 10 km. At completion of the 10-km time trial all post-ingestion measures were repeated, followed by another 50 min rest period. After the second 50 min rest period the participants completed the perceptual, mood and cognitive measures and further blood, urine and saliva samples were collected. Participants returned 24 and 48 h post-ingestion to repeat all post-ingestion measures and another blood, urine and saliva sample was collected. This protocol was then repeated 1 week later for the alternate treatment (placebo or caffeine). The effect of treatment (caffeine, placebo) and the interaction effect of treatment x time were assessed using a repeated measures ANOVA. A student’s t-test was used to measure differences between Leeds sleep evaluation questionnaire (LSEQ) and actigraph data. Results: Fourteen of sixteen participants were heterozygous A/C CYP1A2 for the CYP1A2 genotype and therefore results based on genotypes could not be compared as originally intended. Plasma caffeine, paraxanthine and theophylline concentrations were all elevated following caffeine ingestion (P < 0.05) peaking at 10-km, 1 hour after the 10-km run and 24 hours post caffeine ingestion respectively. Caffeine did not significantly improve 10-km run times. Eccentric leg strength but not concentric leg strength was improved following caffeine ingestion (P < 0.05). Squat jump height but not countermovement jump height was improved following caffeine ingestion (P < 0.05). Digit vigilance reaction times were decreased significantly following caffeine ingestion (P < 0.05) and a trend of decreased rapid visual information processing (RVIP) reaction times were seen (P < 0.1), however, no improvements in the accuracy during cognitive tests were seen following caffeine ingestion. A trend of increased heart rate (P < 0.1) during exercise was observed following caffeine ingestion, but no significant differences in heart rate before and after exercise were observed. Conclusions: While no overall, significant improvements in run time occurred following caffeine ingestion, 11 of 14 participants had a faster run time following caffeine ingestion compared to placebo. Caffeine, rather than the metabolites of caffeine, is likely the main cause of any observed ergogenic effects following caffeine ingestion as the improvements in reaction times, mood and endurance performance occurred when plasma caffeine concentration was elevated but plasma caffeine metabolite concentrations were low. It was found that caffeine ingestion improves endurance performance and reaction times during cognitive tasks. Taken together, the pharmacokinetics of the caffeine and caffeine metabolite peaks suggest that for athletes with the A/C CYP1A2 genotype ingestion of caffeine 1.5 – 2 h prior to an event may be more beneficial for endurance performance compared to the usual recommendations of taking caffeine 1 h prior to exercise. Keywords: caffeine, endurance exercise, CYP1A2, performance, geneticsItem Effect of caffeine supplementation on metabolism and physical and cognitive function in female intermittent games players : a thesis presented in partial fulfilment for the requirements of a Master of Science in Human Nutrition at Massey University, Auckland, New Zealand(Massey University, 2012) O'Donnell, Jemma MayPurpose: To investigate the effects of caffeine ingestion on metabolism and physical and cognitive performance in female team-sport players taking a monophasic oral contraceptive. Method: In a randomized, double-blind, placebo-controlled crossover design, 10 participants (age 23.6 ± 4.1 y; height 1.62 ± 0.06 m; body mass 59.O2 max 50.0 ± 5.3 ml·kg-1·min-1) completed a 90 min intermittent treadmill-running protocol twice, during days 5-8 and 18-22 of their pill cycle. All participants were taking a monophasic oral contraceptive of the same hormonal composition (Levlen ED, Nordette, Monofeme, or Microgynon). During the familiarisation session participants completed a maximal oxygen uptake test, practiced the cognitive, strength, power testing, and underwent 30 min of the running protocol. Upon arrival at the laboratory for the main trials, hydration status was measured via urine specific gravity (USG) using a handheld refractometer and a heart rate (HR) monitor fitted. A capsule containing 6 mg∙kg-1 body mass (BM) of anhydrous caffeine or placebo (Maltodextrin, 1.62 kJ∙g-1) was administered 45 min before commencing exercise with a 500 ml bolus of water. Further 3 ml∙kg-1 BM boluses of water were provided every 15 min during exercise. Before, during and after the exercise protocol, venous blood samples were taken and cognitive (Choice Reaction Time, CRT; Digit Vigilance, DV; Stroop test), perceptual (Ratings of Perceived Exertion, RPE; Feeling Scale, FS; Felt Arousal Scale, FAS; Profile of Mood States, POMS), and physical tests (countermovement jump, CMJ; strength testing on the isokinetic dynamometer) were administered. These tests were then all performed again at a follow-up 12 h post session in the morning, including a venipuncture blood sample, and the addition of sleep quality assessment using the Leeds Sleep Evaluation Questionnaire (LSEQ). Results: There were no significant effects of caffeine supplementation on HR, USG, CMJ, isometric strength, RPE, cognitive performance or glucose and insulin concentrations. Caffeine supplementation improved levels of pleasure, activation and vigour compared to iv placebo, and reduced levels of fatigue (P < 0.05). Caffeine supplementation also improved average power in eccentric contractions of the knee extensors and flexors, and peak torque in the eccentric contractions of the knee flexors (P < 0.05). Getting to sleep and subsequent quality of sleep was impaired following caffeine supplementation (P < 0.05). Free fatty acid (FFA) concentration increased over the duration of exercise (P < 0.05), and increased at a greater rate on the caffeine trial (P < 0.05). Conclusions: This is the first controlled study to examine caffeine supplementation in female games players who are taking a low-dose monophasic oral contraceptive, using an intermittent based running protocol. These athletes experienced an improved performance in various strength and power aspects, but no improvement in cognitive performance. Perceptual and mood responses were also improved as a result of caffeine supplementation. Metabolically, caffeine had an effect on markers of fat metabolism but not on carbohydrate metabolism.