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Item Factors influencing the exertional heat stress response in athletic females : a thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy, School of Sport, Exercise and Nutrition, Massey University, Palmerston North, New Zealand(Massey University, 2022) Zheng, HuixinClimate change continues to expose an increasing proportion of the global population to more frequent extreme heat events. Concurrently, our society has seen an increase in the number of women that participate in physically demanding leisure time (exercise and sport) and occupational activity. Yet, limited research has been conducted to understand the female physiological responses to exercise-heat stress, especially when considering their various ovarian hormone profiles. This thesis expands our understanding of the female physiological responses to heat stress from different perspectives. Firstly, previous evidence has demonstrated that ambient heat stress amplifies the increase in the cytokine interleukin-6 following exercise, an up-regulator of hepcidin - the hormone that downregulates iron metabolism. In Chapter Five iron sufficient females’ serum iron parameters and hepcidin levels following a self-paced cycling work trial were compared in temperate and hot conditions, and different menstrual phases. IL-6 and hepcidin both increased post-exercise (198% and 38%, respectively), interestingly, neither were affected by ambient temperature or menstrual phase (all p>0.15). Chapter Six determined the measurement error of a 30-min self-paced cycling protocol in moderate, warm-dry and warm-humid environments using thirty-three athletic women distinguished by their ovulatory status and ovarian hormone concentrations. With an ICC=0.90, p<0.01, and a mean CV of 4.7%, SEM of 3.8 kJ (2.1 W) and reliable bias of -2.1 kJ (-1.2 W), it was confirmed that this protocol has high test-retest reproducibility that is not influenced by ambient environment or a female’s hormonal/ovulatory status. Finally, in order to better predict females’ risk for exertional heat stress, Chapter Seven attempted to clarify the role of the ovarian hormones when explaining the variance of the core temperature response using the 30-min self-paced cycling protocol from Chapter Six in thirty-six trained women. It was found that estrogen contributes minimally, whilst baseline core temperature and power output contribute the most to peak core temperature during exercise. Taken together, this thesis deepens our understanding of females’ physiological responses and testing norms for current sport science practices. Specifically, it details iron metabolism responses when exposed to exercise-heat stress, elucidates the role of ovarian hormones regarding exertional heat strain and adds test-retest norms specific to athletic women to the available literature.Item Metabolic flexibility and endurance performance : a thesis submitted for the degree of Doctor of Philosophy, School of Sport and Exercise, College of Health, Massey University(Massey University, 2017) O'Connor, William JamesThis thesis examined the sex-specific biochemical, physiological and physical performance responses of highly-trained endurance athletes to chronic moderate and low carbohydrate (CHO) training diets. In addition, a novel exogenous ketone supplement was studied to examine its effects on participants’ physiology and performance during the two contrasting diets. STUDY ONE: This study was designed to test whether adaptation to a low CHO diet affects physical capacity during prolonged exercise. Thirteen highly-trained endurance athletes (eight males, VO₂max = 66.0 ± 9.5 mL·kg⁻¹·min⁻¹ ; five females, VO₂max = 50.6 ± 8.4 mL·kg⁻¹·min⁻¹) consumed a moderate (>5 g CHO·kg⁻¹·day⁻¹) or low (<2 g CHO·kg⁻¹·day⁻¹) CHO training diet for four weeks, in a randomised cross-over design. Performance was measured, after a 24 h moderate CHO “loading” regime, through a self-paced time trial to complete a fixed workload, equivalent to five hours at a workload calculated to elicit 55% VO₂max. Although time-to-complete was not significantly different between diets, the average absolute (watts) and relative (W/kg) power outputs were significantly better on the low CHO diet (p = 0.03 and 0.02 respectively). Both sexes responded similarly in terms of performance, whilst only women significantly improved body composition when CHO was restricted (p = 0.02). It was concluded that when CHO is restricted during training, trained endurance athletes show improved ultra-endurance performance relative to their body mass. STUDY TWO: This study was designed to test the sex specific response to a low CHO diet during fasted endurance exercise. The participants and dietary restrictions were the same as outlined in Study One. Physiological measures were collected before, during and after a two-hour ride at a fixed power output, equivalent to 60 % VO₂max. The ride was undertaken after an overnight (>12 hours) fast and completed at three points throughout each dietary intervention (baseline, week two, week four). As expected there were a significant main effect of diet and time on substrate oxidation rates during fasted exercise (p < 0.05). The low CHO diet resulted in lower CHO oxidation and higher fat oxidation (FATox) in both sexes throughout the exercise. The degree of ‘adaptation’ to low CHO intake increased from baseline to week four, with significant interactions between trial and diet (p < 0.05). There was a sex specific negative correlation between the rate of CHO oxidation and perceived exertion (RPE) at the end of the fasted exercise (p = 0.001). Women consistently had a higher RPE at the end of the exercise (p = 0.04). These data show that both men and women can increase their rates of FATox, in a time-dependent manner, when CHO is restricted in the training diet. STUDY THREE: This study was designed to examine the differences in the blood metabolome of highly-trained male endurance athletes (VO₂max = 6.0 ± 9.5 mL·kg⁻¹·min⁻¹)who each underwent two contrasting dietary interventions, in a randomised crossover design as follows: four weeks moderate (> 5 g CHO·kg⁻¹·day⁻¹) or low (< 2 g CHO·kg⁻¹·day⁻¹) CHO. Exercise training was controlled during both conditions. Fasting venous blood samples were collected before and after exercise at 60% VO₂max and the plasma metabolome was analysed using 700 Hz H1 nuclear magnetic resonance (NMR) spectroscopy. Unsupervised (PCA) and supervised (PLSA-DA & OPLS-DA) multivariate statistical analysis models failed to statistically separate the sample groups in regards to the dietary intervention. However, both methods of supervised discriminant analysis (PLS-DA and OPLS-DA) could separate groups based on time (i.e. pre–post exercise). The variable influence on projection (VIP) was used to identify the individual metabolites causing the group separation within the discriminant analysis. Metabolites were analysed using two-way ANOVA and paired t-tests, with the only significant difference being the blood glucose response to exercise at the end of each dietary intervention (p = 0.006). In conclusion, neither the resting nor exercising metabolome is significantly influenced by the CHO content of the diet. This indicates that endurance-trained individuals possess the metabolic flexibility to counter changes in dietary CHO availability and maintain a normal circulating metabolic profile. STUDY FOUR: The aim of this case study was two-fold: to test the effectiveness of a proposed study, and to explore the validity of reports which have claimed that ingesting a ketone supplement can improve endurance performance. One highly-trained male triathlete (VO₂max = 73.0 mL·kg⁻¹·min⁻¹) completed four time-to-exhaustion (TTE) cycling bouts, each preceded by two hours of cycling at 60% VO₂max (power = 213 W). The exercise bouts were completed in a crossover design as follows: ketogenic diet (< 1.5 g CHO·kg⁻¹·day⁻¹) and regular (non-ketogenic) sports drink (K), ketogenic diet with ketone-containing drink (K+KS), high CHO diet (> 5 g CHO·kg⁻¹·day⁻¹) and regular sports drink (CHO), moderate CHO diet and ketone-containing drink (CHO+KS). Ketosis was confirmed with sustained resting blood β – hydroxybutyrate (β-HB) levels of >0.2 mM. Ketone supplementation was associated with better performance following both dietary interventions, with CHO+KS being better than K+KS (12:54 minutes vs 13:32 minutes, respectively). Ketone supplementation resulted in higher [β-HB] during exercise relative to the sports drink (0.63 & 0.78 mM vs 0.20 & 0.25 mM, respectively). VO₂ and blood lactate did not noticeably differ during the fixed intensity ride, but differed greatly during the TTE, with VO₂ beginning higher on the high CHO diet. The results from this study show the potential benefits of ingesting a ketone supplement on endurance performance and suggest that the moderate CHO status of the individual may have an additive effect. Based on these results, it was suggested that a full scientific study be carried out to further test the effectiveness of ketone supplementation on endurance performance. STUDY FIVE: The aim of this study was to test the effects of ingesting a ketone supplement on endurance performance in two different metabolic states, induced by dietary interventions. Six well-trained male endurance athletes (age: 29 ± 9 yrs, mass: 74.1 ± 7.7 kg, VO₂max: 64.1 ± 5.8 mL·kg⁻¹·min⁻¹) underwent a randomised, double-blinded, placebo-controlled protocol, consisting of two dietary interventions, completed as a cross-over design. Following each dietary intervention, a performance session was carried out, during which, participants drank either a ketone-containing (KS) or placebo (PLB) drink. Thus, the performance session was carried out a total of six times; habitual diet (BASE1, BASE2), moderate-CHO diet + PLB (PLB+CHO), moderate-CHO diet + KS (KS+CHO), ketogenic diet + PLB (PLB+K), ketogenic diet + KS (KS+K). Physiological measures were taken during each performance session, which consisted of a 40-minute fixed intensity ride, followed by a self-paced time trial (TT), to complete a fixed workload equivalent to 20 minutes at 75% VO₂ max. There were no main effects or interactions between diet and KS on TT performance or body mass. The KS significantly increased the beta-hydroxybutyrate concentration [β-HB] in the blood at rest and during exercise (peak = 1.1 mM) (p = 0.001). The KS caused an attenuated blood lactate response during the TT compared to baseline and PLB. The respiratory exchange ratio (RER) was significantly lower on the ketogenic diet at rest and throughout fixed intensity exercise but did not differ during the TT. It is concluded that the circulating [β-HB] attained were not high enough to significantly contribute to muscular energy provision via oxidative phosphorylation and that future research into ketone supplements and exercise performance should ensure that a minimum of 2 mM [β-HB] is obtained. Further, the CHO status of the individual can be largely ignored as supplementation appears to be equally effective irrespective of the CHO status.Item Ground reaction forces and electromyography in a parkour obstacle course : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Sport and Exercise Science at Massey University, Wellington, New Zealand(Massey University, 2019) Austmann, MarcelParkour is a physical discipline that involves athletes, also known as traceurs, using specific skills and movements to overcome obstacles in an urban environment. A typical parkour landing involves an ever-changing combination of variables such as speed, agility, and multiple movement skills that in turn may affect the forces placed on the body. The purpose of the present study was to design a field- based protocol that measured and compared the forces athletes are exposed to in their natural training environment. Methods: A parkour specific obstacle course was designed and five experienced traceurs completed the series of obstacles in succession. Between obstacle comparisons were made for ground reaction force (GRF), time to maximal ground reaction force (TTP), and rate of force development (RFD). Additionally, electromyography was assessed to help better describe underlying mechanisms associated with differences in landing forces. Electrodes were placed bilaterally on the vastus lateralis (VL), gastrocnemius (GM), and the tibialis anterior (TA) and area (%MVIC) was used to represent muscle activation. Results: GRF was highest in obstacles with larger drop heights as well as increased momentum from previous obstacles which includes obstacles 2a-floor, 4-floor, and 2c-floor. The lowest TTP values were associated with obstacles involving short landing contact time due to limited space which includes obstacles 3-4, 2c-floor, and 1-floor. RFD was greatest in obstacles 2a- floor, 3-4, 4-floor, 9-floor, and 2c-floor which all required explosive power upon landing in order to complete subsequent obstacles. EMG data showed that the GM and VL had greater activation on obstacles requiring either a change in direction such as 6b-7 and/or a rapid descent such as obstacles 7-8 and 8-floor. TA showed higher activations on obstacle 9-floor and 2b-2c, but activations were similar across most obstacles. The activation of the TA may be due to its role in eccentrically contracting during initial foot strike during landing. Conclusion: Due to the dynamic nature of parkour, athletes are often exposed to a variety of landings which would produce diverse kinetic demands. By using a parkour specific course, this study provided force data that was a close representation of the forces traceurs are exposed to in a typical parkour run.Item Can backward sled towing potentiate five metre sprint performance? : a thesis presented in partial fulfilment of the requirements for the degree of Master of Sport and Exercise at Massey University, Palmerston North, New Zealand(Massey University, 2019) Monaghan, Daniel JohnPost-activation potentiation (PAP) describes an augmentation within muscle properties, with the ability to enhance muscular performance. Due to the complexity of this highly individualised phenomenon, PAP has the greatest effect in well-trained populations. Back squat, sled towing, and sled pushing protocols have shown to acutely improve 20 m sprint performance. Potentiating activities that reflect the specific movement profiles of the performance activity are proposed as most effective, suggesting a possible relationship between muscle specific potentiation and augmented sprint performance. Therefore, the use of a quadriceps dominant sprint related exercise (i.e., backward sled towing) may acutely enhance sprint performance. The objectives of this study were to determine whether backward sled towing can elicit a PAP response to enhance 5 m sprint performance, and to determine if sled loading via a reduction in velocity can elicit an improvement in 5 m sprint performance. A randomised design was used to examine the effects of forward and backward sled tow loading of 35% and 55% reduction of individual’s maximal velocity (rVelmean) on 5 m sprint performance. Eighteen participants performed one familiarisation session, followed by four intervention sessions (55% rVelmean backward; 55% rVelmean forward; 35% rVelmean backward; 35% rVelmean forward) separated by a minimum of 24-hours. Intervention sessions included baseline un-resisted 5 m sprints, and the collection of maximum voluntary contractions of lower limb musculature via surface electromyography (EMG), followed by three loaded sled tows over a distance of 3.2 m or 5 m for heavy and light loads, respectively. An un-resisted 5 m sprint was then completed following 6 and 12 min rest. Mean sprint velocity, EMG, and sprint kinematic and temporal data were collected during each session. EMG was used to determine if a potentiated effect was due to changes in neural excitation. Sled towing, irrespective of load or rest period, produced no significant change in 5 m sprint velocity (p > 0.05). Significant difference was found between both 35% and 55% backwards calculated velocity reduction and actual velocities during towing (p < 0.01). There was no significant change in EMG across sessions. Kinetic and temporal data suggested no significant changes in baseline measures; however, current findings highlight the importance of vertical force production during sprint acceleration. Sled towing to potentiate sprint performance using a reduction of velocity requires further investigation. The author acknowledges that greater time under tension during conditioning activities may result in greater sprint related potentiation. However, further research is required to assess the legitimacy of this speculation.Item Nutrition knowledge, muscle strength and physical activity participation in independently living older men and women : a thesis completed as part of the requirements for Master of Science in Nutrition and Dietetics at Massey University, Albany Campus Auckland, New Zealand(Massey University, 2019) De Villiers, BaronAim: To investigate nutrition knowledge and characterise the physical typologies of older men and women residing in a retirement village based on their age, anthropometry and levels of physical activity. Methods: A single-centred cross-sectional study among 43 older New Zealand men and women living independently in a retirement village. Participants (20 men and 23 women) completed a nutrition knowledge questionnaire and anthropometry, body composition (bioelectrical impedance analysis; BIA), grip strength (handgrip dynamometer), Five Times Sit to Stand (FTSS), gait speed and physical activity (accelerometer) testing. Results: Four distinct physical typologies: ‘strong sedentary’, ‘weak sedentary’, ‘overweight active’ and ‘lean active’. The two sedentary typologies scored in the normative ranges in the three physical measures. Strong sedentary and overweight active men were stronger (P<0.05) and had a higher BMI (P<0.001). Lean active women recorded higher weekly step counts (P<0.001), higher levels of light and moderate activity (P<0.001) and were less sedentary (P<0.001). High levels of nutrition knowledge with mean NAK-50+ questionnaire score >74% for both men and women. No significant nutrition knowledge associations were found between men and women (P=0.372). Each typology scored above frailty cut-offs in each physical function test (handgrip, FTSS and gait speed). Conclusions: Among Four distinct physical typologies there were no significant nutrition knowledge associations between the groups. More research is needed to further understand the role of nutrition knowledge in older adults related to body composition and typologies. High levels of physical activity and function were evident among these independent older adults indicative of low risk for loss of independence.Item The effects of post-training hot water immersion on concurrent training load and treadmill running performance in the heat : a thesis presented in partial fulfilment of the requirements for the degree of Master of Sport & Exercise in Exercise and Sport Science at Massey University, Albany, New Zealand(Massey University, 2019) Stewart, JoshuaBackground: Team-sport athletes of both elite and sub-elite status are often required to travel to hot and/or humid environments for competition; however, preparing for these environmental challenges can be difficult within a team-sport setting. Heat acclimation (HA) strategies for team-sports can typically involve the use of expensive equipment, or travel in advance of competition to naturally acclimatise to the competition environment; these may also affect the quality of concurrent training. These logistical challenges often faced by team-sports when preparing for competition in hot environments often dictate what is (un)available to them. Post-training hot water immersion (HWI) has emerged as a passive approach that is logistically friendly for sporting teams to use during a preparatory period for competition in the heat. Aim: To investigate if 6-days of post-training HWI is an effective HA strategy for sub-elite, male, team-sport athletes, has any detrimental effects on concurrent training load and if it can improve aerobic capacity in the heat. Methodology: In a randomised control study, fifteen, non-acclimatised, moderately-trained males performed an intermittent running protocol in temperate outdoor conditions (18°C, 67% RH) for six consecutive days followed by a post-training cool-down (CON; n=8) or an additional 40 min of HWI in 38°C (n=7). Three days before and two days following the intervention, participants completed a RAMP treadmill run in the heat (33°C, 30% RH). Results: The HWI group displayed a reduced mean heart rate (p=0.02) during immersion from day-1 to day-6 (by 14±10 beats‧min⁻¹) and improved feelings (by 0.9±0.5 AU; p=0.003). Daily HWI had no detrimental effects on concurrent training as no significant differences (all p<0.05) were found between groups for total distance run, session RPE and the composite measure of training load (duration x RPE). Treadmill VO2peak improved from pre-post for the HWI group (by 2.1 ml‧kg⁻¹‧min⁻¹or 4.2%; p=0.003) but not the CON group (0.2 ml‧kg⁻¹‧min⁻¹ or 0%; p=0.88). Conclusions: Six consecutive days of post-training HWI induces partial HA in moderately trained team-sports athletes with no detrimental effects on concurrent training load. This provides a practical acclimation strategy for sporting teams to implement when preparing for competition in the heat that acknowledges the logistical challenges often faced.Item Investigating eating behaviours as predictors of body composition and dietary intake in New Zealand European, Māori and Pacific women - the women's EXPLORE study : a thesis presented in partial fulfilment of the requirements for the degree Master of Science in Nutrition and Dietetics, Massey University, Albany, New Zealand(Massey University, 2018) Shepherd, Katrina JadeBackground/Aim: Internationally, eating behaviour has been linked with an optimal and adverse body composition in women. However no study to date has examined eating behaviour in female New Zealand ethnic groups. Therefore, the aim of this study was to investigate eating behaviours as predictors of different body composition factors and dietary intake in New Zealand European (NZE), Māori and Pacific women, aged 16-45 years, participating in the women’s EXPLORE study. Methods: Women (N=368) were assessed for basic anthropometry, total adiposity, regional adipose distribution and lean mass using height, weight, circumferences, dual x-ray absorptiometry and air-displacement plethysmography. Body composition profiles (normal-fat, hidden-fat and apparent-fat) were established using parameters of body mass indices and body fat percentages. The validated Three-Factor Eating Questionnaire (TFEQ) and New Zealand Women’s Food Frequency Questionnaire were both used to examine eating behaviour and dietary intake, respectively. The TFEQ examined Restraint (Flexible and Rigid), Disinhibition (Habitual, Emotional and Situational) and Hunger (Internal and External). Combinations of behaviour (sub-groups) were established from the main categories and also examined. Results: Restraint was significantly higher in NZE than Pacific women (p = 0.015). Disinhibition was significantly higher in the apparent-fat profile than normal-fat profile (p < 0.001). Likewise, Hunger was significantly higher in Pacific (p < 0.001) and the apparent-fat profile (p = 0.034) than NZE women and women with normal-fat profile, respectively. Adverse tendencies of Habitual Disinhibition, and External Hunger were more prominent in Pacific and the apparent-fat profile than NZE women and normal-fat profile, respectively (all p < 0.05). External Hunger was more prominent in the hidden-fat profile than normal-fat profile (p = 0.001). When accounting for age and ethnicity the most significant predictors of BMI and BF % were Restraint (p = 0.007 and p = 0.005 respectively), Disinhibition (both p < 0.001), Habitual Disinhibition (both p < 0.001) and Emotional Disinhibition (both p < 0.001). Non-ideal behaviour combinations (Low Restraint High Disinhibition and High Hunger High Disinhibition) generally corresponded to significantly higher body composition markers and dietary intake (p < 0.05). Pacific women were three times more likely to have High Hunger High Disinhibition than NZE women (p = 0.004). Low Restraint High Disinhibition and High Hunger High Disinhibition increased by 12% and 11%, respectively from the normal-fat profile to hidden-fat profile (both p < 0.001). Conclusions: The TFEQ eating behaviour categories, sub-categories and sub-groups can significantly vary between ethnicities and body composition groups. Tailored interventions to promote Restraint (particularly Flexible Restraint) and counteract Disinhibition (particularly Habitual Disinhibition and Emotional Disinhibition), Hunger (particularly External Hunger), Low Restraint High Disinhibition and High Hunger High Disinhibition could enhance eating behaviour and dietary intake and help optimise weight management in young New Zealand women.Item Biomechanics of stationary exercise : an option for weight management : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Massey University, Wellington, New Zealand(Massey University, 2018) Yaghoubi, MostafaChildren carrying excess mass have difficulty performing exercises requiring whole body movement with horizontal displacement, such as walking and running. While previous research strongly suggests that overweight children adapt their gait to accommodate for moving excess mass horizontally, very little research has investigated the biomechanical characteristics of simple exercises that focus on vertical displacement, such as stationary exercise. In addition, aquatic exercise has not been considered as an alternative solution for this population. Therefore, the purpose of this thesis was to compare the biomechanical differences between aquatic- and land-based stationary exercises in normal-weight and overweight children. Methods This thesis involved four parts; literature review, technical note, biomechanics of land- and aquatic-based stationary exercise. The literature review includes a summary about the prevalence of paediatric obesity and its related physical dysfunction, as well as the drafted literature review manuscript on biomechanical differences in exercises overground and within shallow water. It is followed by a technical note study to examine the accuracy of the camera setup by comparing the angular kinematics collected using a recreational, low-cost sports video camera (GoPro, Inc) and commercial inertial motion sensors, in both land and water environments. Following the validation study, there are two cross-sectional studies that investigate the differences in lower extremity kinematics, spatiotemporal parameters, rate of perceived exertion (RPE) and muscle activation patterns, in normal-weight and overweight children during water- and land-based stationary exercises. Results The literature review revealed that the previous aquatic biomechanical research is limited to aquatic gait in adults and elderly people. The lack of aquatic research in children is of great concern, as aquatic sports provide a low weight bearing activity that diminishes the likelihood of injuries in children and provides a solid foundation for physically activity throughout the lifespan. We demonstrated that the GoPro camera derived angular velocity measurements underwater and in air are accurate when compared to data from inertial sensors and known motion of the clock's second hand and a driven limb segment model. Thus, the accuracy of thesis protocol was established. The findings of the two cross-sectional studies demonstrated that children with excess body mass experienced significantly greater RPE and muscle activation with more extended joints during land-based stationary exercises. However, these differences diminished between groups in water with a lower RPE in overweight children and a more upright posture for both groups. Conclusions These findings suggested that children with excess body mass may adopt a more active neuromuscular strategy and a more upright posture in order to provide greater stability and propulsion during land-based stationary exercises. Higher RPE scores could indicate a greater level of difficulty and lack of enjoyment when performing stationary exercise on land. However, these differences did not exist in water. Thus, these findings support stationary exercises in water as a desirable way to reduce functional differences and subsequently promote physical activity in overweight children.Item Human temperature regulation during exercise in the heat : effects of the menstrual cycle and ambient thermal profile : a thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy, School of Sport, Exercise and Nutrition, Massey University, Palmerston North, New Zealand(Massey University, 2018) Lei, Tze-HuanBehavioural thermoregulation is the most effective means with which we regulate our body temperature at rest and during exercise. Yet, research into behavioural thermoregulation during exercise is still at an emergent stage, as it has not included females, or investigated different thermal profiles. In particular, limited studies are available to describe the behavioural and physiological differences between dry and humid heat for both sexes. Furthermore, it remains unknown whether ambient humidity or temperature alone contribute to the initiation of the behavioural responses during exercise in the heat. Therefore, the first part of this thesis investigated the effects of endogenous and exogenous female ovarian hormones on behavioural and autonomic responses, in both dry and humid heat environments matched according to the heat stress index, WBGT (Chapter Five and Six). The results from Chapter Five clearly show that behavioural and autonomic responses were less affected by menstrual phase, but were affected by the environmental conditions. In particular, trained women reduced their power output in order to nullify the autonomic strain from a humid heat environment. Chapter Six then extended this observation to (trained) women taking combined hormonal contraception, compared to eumenorrheic women in Chapter Five. The results from Chapter Six indicate that greater autonomic strain was observed in women with hormonal contraception, compared to eumenorrheic women, in both dry and humid heat, whilst the behavioural response was similar between those two groups. Furthermore, the behavioural response was different between dry and humid heat, with power output being lower in the humid heat environment compared to dry heat. The second part of this thesis investigated the effects of ambient temperature per se on the interaction of thermoregulatory, cardiovascular and perceptual responses to exercise (Chapter Seven), as well as assessing different exercise modalities (variable-intensity versus fixed-intensity exercise) and their effects on thermoregulation when the duration and average power output were matched (Chapter Eight). The results from Chapter Seven indicate that thermoregulatory and cardiovascular responses were not affected by ambient temperature but that perception was, when vapour pressure was matched between two different thermal profiles. The results from Chapter Eight indicate that self-pacing (behaviour) did not modulate thermoregulatory strain, when both self-paced and fixed-intensity were matched at the same exercise intensity and duration. In conclusion, this thesis extends the knowledge-base on behavioural thermoregulation in trained women and also provides evidence that behavioural and autonomic thermoregulation is influenced more by vapour pressure than ambient temperature of the environment in men. Furthermore, the findings of this thesis confirm that behavioural thermoregulation is effective in modulating physiological strain only when there is a reduction in metabolic heat production.Item The relationship between daily mood and salivary immunoglobulin A : a thesis presented in partial fulfilment of the requirements for the degree of Master of Arts in Psychology at Massey University(Massey University, 1991) Binnie, Jan ElizabethThe aim of the present study was to examine the influence of daily positive and negative mood on secretory immunoglobulin A (S-lgA) concentrations in human saliva. An instrument was constructed for the measurement of daily mood, based on current theories in the psychobiology of affect, neuroendocrinology and behaviour. With this instrument the average intensity, peak intensity and duration of eight moods, two from each pole of positive and negative affect dimensions, were measured. From these scores three positive affect variables were created by combining scores on positive dimension moods, and three negative affect variables created by combining scores on negative dimension moods, and these variables were used for multivariate analysis. Twenty female subjects between the ages of 18 and 60 years were studied for 28 consecutive days. They were each required to capture 1.5 ml of free flowing parotid saliva, fill in the mood questionnaire, and record whether or not they had taken medication, exercise, alcohol, tobacco or menstruated on each evening of the study. These last variables were subsequently used as control variables in the multivariate analysis. Concentrations of S-lgA in the saliva were measured with an enzyme-linked immunosorbent assay (ELISA). No significant associations between S-lgA levels and positive or negative mood variables were detected. The lack of significant effects of mood variables on S-lgA is discussed in the context of the psychoneuroimmunological literature, and with particular emphasis on measurement issues.