Oral application of L-menthol in the heat: From pleasure to performance

When menthol is applied to the oral cavity it presents with a familiar refreshing sensation and cooling mint flavour. This may be deemed hedonic in some individuals, but may cause irritation in others. This variation in response is likely dependent upon trigeminal sensitivity toward cold stimuli, suggesting a need for a menthol solution that can be easily personalised. Menthol’s characteristics can also be enhanced by matching colour to qualitative outcomes; a factor which can easily be manipulated by practitioners working in athletic or occupational settings to potentially enhance intervention efficacy. This presentation will outline the efficacy of oral menthol application for improving time trial performance to date, either via swilling or via co-ingestion with other cooling strategies, with an emphasis upon how menthol can be applied in ecologically valid scenarios. Situations in which performance is not expected to be enhanced will also be discussed. An updated model by which menthol may prove hedonic, satiate thirst and affect ventilation will also be presented, with the potential performance implications of these findings discussed and modelled. Qualitative reflections from athletes that have implemented menthol mouth swilling in competition, training and maximal exercise will also be included

An effect of physical exercise-induced fatigue on the vital sign parameters: a preliminary study

Vital sign monitoring is an important body measurement to identify health condition and diagnose any disease and illness. In sports, physical exercise will contribute to the changes of the physiological systems, specifically for the vital signs. Therefore, the objective of this study was to determine the effect of physical fatigue exercise on the vital sign parameters. This is significant for the fitness identification and prediction of each individual when performing an exercise. Five male subjects with no history of injuries and random BMI were selected from students of biomedical engineering, Universiti Teknologi Malaysia. Based on the relationship between physical movement and physiology, the parameters considered were heart rate, blood pressure, and body temperature. Subjects were required to run on the treadmill at an initial speed of 4 km/h with an increase of 1 km/h at every 2 minutes interval. The effect of exercise was marked according to the fatigue protocol where the subject was induced to the maximum condition of performance. All parameters were measured twice, for pre and post exercise-induced protocol. The analysis of relationship of each parameter between pre and post fatigue was p<0.05. The results revealed that the heart rate and gap between blood pressure’s systolic and diastolic were greater for all categories except underweight, where the systolic blood pressure dropped to below 100mmHg at the end of exercise. Also, the body temperature was slightly declined to balance the thermoregulatory system with sweating. Hence, the vigorous physical movement could contribute to the active physiological system based on body metabolism. Heart rate and blood pressure presented significant effects from the fatiguing exercise whereas the body temperature did not indicate any distinguishable impact. The results presented might act as the basis of reference for physical exercise by monitoring the vital sign parameters

Health State Estimation

Life's most valuable asset is health. Continuously understanding the state of our health and modeling how it evolves is essential if we wish to improve it. Given the opportunity that people live with more data about their life today than any other time in history, the challenge rests in interweaving this data with the growing body of knowledge to compute and model the health state of an individual continually. This dissertation presents an approach to build a personal model and dynamically estimate the health state of an individual by fusing multi-modal data and domain knowledge. The system is stitched together from four essential abstraction elements: 1. the events in our life, 2. the layers of our biological systems (from molecular to an organism), 3. the functional utilities that arise from biological underpinnings, and 4. how we interact with these utilities in the reality of daily life. Connecting these four elements via graph network blocks forms the backbone by which we instantiate a digital twin of an individual. Edges and nodes in this graph structure are then regularly updated with learning techniques as data is continuously digested. Experiments demonstrate the use of dense and heterogeneous real-world data from a variety of personal and environmental sensors to monitor individual cardiovascular health state. State estimation and individual modeling is the fundamental basis to depart from disease-oriented approaches to a total health continuum paradigm. Precision in predicting health requires understanding state trajectory. By encasing this estimation within a navigational approach, a systematic guidance framework can plan actions to transition a current state towards a desired one. This work concludes by presenting this framework of combining the health state and personal graph model to perpetually plan and assist us in living life towards our goals.Comment: Ph.D. Dissertation @ University of California, Irvin

Non-Invasive Examination of the Role of Local Muscle O2 Delivery in Determining VO2 Kinetics During Moderate-Intensity ‘Step’ and Ramp Incremental Exercise

This thesis was undertaken to examine the physiological mechanisms that interact to govern the adjustment of O2 uptake (VO2) during the on-transient of moderate-intensity exercise as well as during incremental exercise, using non-invasive measures. Particular emphasis was placed on the information provided by pairing breath-by-breath pulmonary VO2 measures with near-infrared spectroscopy (NIRS)-derived measures to investigate the role of local muscle O2 delivery in the determination of VO2 during various exercise challenges. The main findings were that: 1) local muscle O2 delivery likely plays a rate-limiting role in the determination of τVO2p (at least when τVO2p is greater than ~20 s), even in young, healthy adults; 2) τVO2p can be reduced by augmenting local muscle O2 delivery (with heavy-intensity ‘priming’ exercise) and increased by impairing local muscle O2 delivery (with acute, mild hypoxia); 3) the relative slowing of the VO2 on-kinetics response when moderate-intensity exercise is initiated from an elevated baseline WR does not appear to be the result of reduced local muscle O2 delivery in older adults; 4) whereas the effects of moderate-intensity work rate (WR) increment were heterogeneous with respect to τVO2p in those with fast versus slow VO2 kinetics, increasing WR increments were associated with increasing O2 costs (i.e., functional gain; G = ΔVO2/ΔWR) regardless of the rate of adjustment; this suggests that τVO2p and functional G may be dissociated; and 5) the appropriateness of a sigmoid regression to characterize the overall Δ[HHb] response to incremental exercise (at least for comparative purposes) was challenged, and a ‘double-linear’ model was proposed as an alternative

Characterisation of cardiorespiratory responses to electrically stimulated cycle training in paraplegia

Functional, electrically stimulated (FES) cycle training can improve the cardiorespiratory fitness of spinal cord injured (SCI) individuals, but the extent to which this can occur following high volume FES cycle endurance training is not known. The effect of training on aerobic endurance capacity, as determined by the appearance of respiratory gas exchange thresholds, is also unknown. The oxygen cost (O2 cost) of this type of exercise is about 3.5 times higher than that of volitional cycling, but the source of this inefficiency, and of the variation between subjects, has not yet been investigated. The electrical cost of FES cycling, measured as the stimulation charge required per Watt of power produced (stim/Pt), has neither been calculated nor investigated before. It is also not known whether a period of FES cycling can alter the O2 cost or the stim/Pt of this unique form of exercise. Additionally, the acute metabolic responses to prolonged, high intensity FES cycling after a 12-month period of high-volume training have not yet been characterised for this subject group. Accordingly, these parameters were investigated over the course of a 12-month homebased FES cycle training programme (up to 5 x 60 min per week) in 9 male and 2 female individuals with paraplegia. Outcomes were investigated using a novel, sensitive test bed that accounted for both internal and external power production (Pt). The test protocol permitted high resolution analyses of cycling power and metabolic thresholds, and a sensitive training dose-response analysis, to be performed for the first time in FES cycling. Efficiency estimates were calculated within a new theoretical framework that was developed for those with severe disability, and the stim/Pt was determined using a novel measure designed for this study. The current training programme resulted in significant improvements in cardiorespiratory fitness and peak cycling power, but only over the first 6 months when training was progressive. These improvements were positively related to the number of training hours completed during this time. It is not known whether the plateau in training response that was found after this time was due to a physiological limitation within the muscles, or to limitations in the current stimulation strategy and of the training protocol used. The efficiency of FES cycling was not significantly altered by any period of training. However, the stim/Pt of cycling had reduced over the first 6 months, probably as a result of a fibre hypertrophy within the stimulated motor units. The relationship that was found between variables after this time suggest that differences in the efficiency of FES cycling ii between subjects and over time related primarily to the stim/Pt, which determined the number of motor units recruited per unit of power produced, rather than to metabolic changes within the muscle itself. The aerobic gas exchange threshold (GET) was detected at an oxygen uptake (˙VO2) equivalent to that normally elicited by very gentle volitional exercise, even after training. This provided metabolic evidence of anaerobic fibre recruitment from the outset, as a consequence of the non-physiological motor unit recruitment pattern normally found during FES. The cardiorespiratory stress of training was found to be significantly higher than that elicited by the incremental work rate tests, calling into question the validity of using traditional, continuous incremental work rate tests for establishing the peak oxygen uptake (˙VO2peak) of FES cycling. The respiratory exchange dynamics observed over a 60 min training session were characterised and provide a unique insight into the remarkable aerobic and anaerobic capacity of trained paralytic muscles. For this particular highly motivated subject group, training for 60 min per day on more than 4 days of the week was demonstrated to be feasible, but not able to be sustained. Further work is therefore recommended to develop and to evaluate different stimulation patterns and parameters, loading strategies and training protocols. The aim would be to determine the optimal combination of training parameters that would maximise favourable training responses within a more viable and sustainable lower volume, training programme for this subject group. In conclusion, the outcomes of this multi-centre study have demonstrated the clinical significance of using otherwise redundant, paralytic leg muscles to perform functional, regular physical exercise to improve cardiorespiratory and musculoskeletal health after SCI. Additionally, the significant increases in cycling power and endurance that were achieved opened up new mobility and recreational possibilities for this group of individuals. These findings highlight the clinical and social relevance of regular FES cycle training, and the importance of integrating FES cycling into the lives of those affected by SCI. The early and judicious implementation of this form of exercise is strongly recommended for the maintenance of a healthy body, wellbeing, and of an active lifestyle after SCI

Exercise, glucose control and liver fat :providing the evidence for translation into clinical care

PhD ThesisNon-alcoholic fatty liver disease (NAFLD) has become the most common form of liver disease throughout much of the World. It affects between one in five and one in three adults in the general population. It is now believed to be the leading cause of liver cirrhosis and hepatocellular carcinoma. However, the majority of people with NAFLD do not go on to develop terminal liver disease but instead have an uncertain prognosis that can often include type 2 diabetes, cardiovascular disease, and/or non-hepatic cancers. Indeed, NAFLD is frequently accompanied impaired glucose control, and almost always suboptimal insulin sensitivity. This thesis explores the only currently recommended therapy – weight reduction by lifestyle modification. It reviews the published evidence supporting this recommendation by applying a systematic approach to review the literature, but examines the findings in the broader context of common NAFLD comorbidities and sequelae. It also examines interaction of age and physical activity with liver fat, specifically in women, using both primary and secondary research methods. Finally, it explores exercise, particularly high-intensity intermittent training as a means to reduce liver fat, improve body composition, and attenuate insulin resistance independent of weight change and dietary advice. The principle finding is that, although the literature supports the recommendation of weight reduction, exercise can be an effective therapy to reduce liver fat and improve glucose control/insulin independent of weight change in adults with NAFLD. High-intensity intermittent training is particularly ii effective for liver fat reduction, improves glucose control/insulin resistance, and results in positive changes to body composition