Professor John O'Hara, Professor

Professor John O'Hara

Professor

John O'Hara is a Professor in Sport and Exercise Physiology. His research interests are in the area of sport performance, including: carbohydrate metabolism; physiological changes at high altitude; hydration status; global position tracking.

John completed his first degree in Sport and Exercise Science, followed by a Masters in Sport and Exercise Science at Leeds Beckett University. He then went on to complete his PhD with Professor Roderick King at Leeds Beckett University. His PhD studies focussed on pre-exercise carbohydrate ingestion: rebound hypoglycaemia, fuel utilisation and endurance capacity in male cyclists.

John has worked at Leeds Beckett University as an academic member of staff since 2000, becoming a Professor in Sport and Exercise Physiology in 2015. John is a local research ethics co-ordinator and is a co-opted member to the University research ethics committee. John acts as a research mentor to academic colleagues. Further he delivers on physiology and nutrition modules at under-graduate and post-graduate level, as well as supervising PhD students within the Carnegie School of Sport. He is a Senior Fellow of the Higher Education Academy.

John is an accredited sport scientist with the British Association of Sport and Exercise Sciences (BASES), as well as being a Chartered Scientist with the Science Council. He also acts as the Director of the physiology research laboratories within the Carnegie School of Sport. John is an experienced applied sport scientist having worked with amateur and professional athletes across a range of sporting disciplines for many years.

Current Teaching

  • PhD Supervisor and Director of Studies
  • Delivers on physiology and nutrition modules across the sport and exercise science under-graduate and post-graduate provision within the Carnegie School of Sport.

Research Interests

John is involved in research related to carbohydrate metabolism, supervising several PhD students. He was awarded a "Promising Research Fellowship" by Leeds Beckett University (February 2011 to June 2011), which provides an opportunity to develop the use of 13C stable mass isotopes within our carbohydrate metabolism research. These techniques allow the quantification of exogenous and endogenous (muscle and liver) carbohydrate oxidation during exercise and are now used routinely within our research.

John is collaborating with researchers from the Defence Medical Service (DMS) hypoxic study group on a number of projects related to physiological changes at high altitude. He is currently undertaking research projects with the DMS, investigating the effects of high altitude exposure on carbohydrate metabolism, as well as hormonal responses in relation to acute mountain sickness.

John is also leading research assessing the movement and physiological demands of Rugby League referees within the European Super League.

John has also used his research expertise to secure funding from commercial companies to carry out research or product development.

Professor John O'Hara, Professor

Selected Outputs

  • Ispoglou T; Jones B; Bradley P; O'hara J (2015) Is there a place for static stretching in warm-up routines of soccer players?. In: World Congress on Science and Football 2015, 21 May 2015 - 23 May 2015, Copenghagen, Denmark.

  • Emmonds S; O'Hara J; Till K; Jones B; Brightmore A; Cooke. C (2014) The effect of distance covered, number of high intensity efforts and heart rate on the decision-making accuracy of professional Rugby League referees. In: The British Association of Sport and Exercise Sciences (BASES) conference, 25 November 2014 - 26 November 2014, St George’s Park, Burton upon Trent, UK.

    https://doi.org/10.1080/02640414.2014.968386

  • Brightmore AM; O'Hara J; Till K; Cobley S; Hubka T; Emmonds S; Cooke C (2014) Comparison of movement demands in Rugby League referees between the European Super League and Australasian National Rugby League. In: The British Association of Sport and Exercise Sciences (BASES) conference, 25 November 2014 - 26 November 2014, St George’s Park, Burton upon Trent, UK.

    https://doi.org/10.1080/02640414.2014.968386

  • Boos C; Holdsworth D; Woods D; O'Hara J; Brooks N; Macconnachie L; Bakker-Dyos J; Paisey J; Mellor A (In press) Assessment of Cardiac Arrhythmias at Extreme High Altitude Using an Implantable Cardiac Monitor: REVEAL HA Study. Circulation, 135 (8), pp. 812-814.

    https://doi.org/10.1161/CIRCULATIONAHA.116.026584

  • Rowe J; King R; King A; Wilson O; Morrison D; Preston T; O'Hara J (2021) Glucose and Fructose Hydrogel Enhances Running Performance, Exogenous Carbohydrate Oxidation and Gastrointestinal Tolerance. Medicine and Science in Sports and Exercise, 54 (1), pp. 129-140.

    https://doi.org/10.1249/MSS.0000000000002764

  • Marshall AR; Rimmer JE; Shah N; Bye K; Kipps C; Woods DR; O'Hara J; Boos CJ; Barlow M (2021) Marching to the Beet: The effect of dietary nitrate supplementation on high altitude exercise performance and adaptation during a military trekking expedition. Nitric Oxide, 113-11 pp. 70-77.

    https://doi.org/10.1016/j.niox.2021.05.002

  • Parsons I; Snape D; O'Hara J; Holdsworth D; Stacey M; Gall N; Chowienczyk P; Wainwright B; Woods D (2020) Echocardiographic changes following active heat acclimation. Journal of Thermal Biology, 93 pp. 102705.

    https://doi.org/10.1016/j.jtherbio.2020.102705

  • Shah N; Bye K; Marshall A; Woods DR; O'Hara JP; Barlow M; Rimmer J; Boos C (2020) The Effects of Apnoea (hypoxia) Training, using voluntary Breath Holds, on High Altitude Adaptation: BREATHE-HA Study. High Altitude Medicine and Biology

    https://doi.org/10.1089/ham.2019.0087

  • Elia A; Barlow M; Wilson O; Deighton K; O'Hara JP (2019) Erythropoietic responses to a series of repeated maximal dynamic and static apnoeas in elite and non-breath-hold divers. European Journal of Applied Physiology

    https://doi.org/10.1007/s00421-019-04235-1

  • King A; O'Hara JP; Arjomandkah N; Morrison D; Preston T; King R (2019) Liver and Muscle Glycogen Oxidation and Performance with Dose Variation of Glucose-Fructose Ingestion During Prolonged (3-hours) Exercise. European Journal of Applied Physiology, 119 pp. 1157-1169.

    https://doi.org/10.1007/s00421-019-04106-9

  • Griffiths A; Shannon O; Matu J; King R; Deighton K; O'Hara J (2019) The effects of environmental hypoxia on substrate utilisation during exercise : A meta-analysis. Journal of the International Society of Sports Nutrition, 16 (10),

    https://doi.org/10.1186/s12970-019-0277-8

  • Hill N; Deighton K; Matu J; Misra S; Oliver N; Newman C; Mellor A; O'Hara JP; Woods D (2018) Continuous Glucose Monitoring – effects of altitude on glucose and glycaemic variability. Medicine and Science in Sports and Exercise, 50 (8), pp. 1679-1686.

    https://doi.org/10.1249/MSS.0000000000001624

  • Cooke M; Cruttenden R; Mellor A; Lumb A; Pattman S; Burnett A; Boot C; Burnip L; Boos C; O'Hara JP (2018) A pilot investigation into the effects of acute normobaric hypoxia, high altitude exposure and exercise on serum angiotensin-converting enzyme, aldosterone and cortisol. Journal of the Renin-Angiotensin-Aldosterone System, 19 (2),

    https://doi.org/10.1177/1470320318782782

  • Boos C; Bass M; O'Hara JP; Vincent E; Mellor A; Sevier L; Abdul-Razakq H; Cooke M; Barlow M; Woods DR (2018) The relationship between anxiety and acute mountain sickness. PLoS One, 13 (6),

    https://doi.org/10.1371/journal.pone.0197147

  • King R; Jones B; O'Hara JP (2018) The availability of water associated with glycogen during dehydration; a reservoir or raindrop?. European Journal of Applied Physiology, 118 (2), pp. 283-290.

    https://doi.org/10.1007/s00421-017-3768-9

  • King A; O'Hara JP; King R (2018) Carbohydrate Dose Influences Liver and Muscle Glycogen Oxidation and Performance during Prolonged Exercise. Physiological Reports

    https://doi.org/10.14814/phy2.13555

  • Clarke SB; Deighton K; Newman C; Nicholson G; Gallagher L; Boos C; Mellor A; Woods D; O'Hara JP (2018) Changes in balance and joint position sense during a 12-day high altitude trek: The British Services Dhaulagiri medical research expedition. PLoS ONE

    https://doi.org/10.1371/journal.pone.0190919

  • Howard M; Bakker-Dyos J; Gallagher L; O'Hara JP; Woods D; Mellor A (2017) Power Supplies and Equipment for Military Field Research : lessons from the British Service Dhaulagiri Research Expedition 2016. Journal of the Royal Army Medical Corps, 164 (1),

    https://doi.org/10.1136/jramc-2017-000767

  • Boos C; Vincent E; Mellor A; O'Hara JP; Newman C; Cruttenden R; Scott P; Cooke M; Matu J; Woods D (2017) The effect of Sex on Heart Rate Variability at High Altitude. Medicine and Science in Sports and Exercise, 49 (12),

    https://doi.org/10.1249/MSS.0000000000001384

  • Mellor A; Bakker-Dyos J; Howard M; Boos C; Cooke M; Vincent E; Scott P; O'Hara J; Clarke S; Barlow M (2017) The British Services Dhaulagiri Medical Research Expedition 2016 : a unique military and civilian research collaboration. Journal of the Royal Army Medical Corps, 163 (6), pp. 371-375.

    https://doi.org/10.1136/jramc-2016-000700

  • Parker P; Manley A; Shand R; O'Hara JP; Mellor A (2017) Working memory capacity and surgical performance whilst exposed to mild hypoxic hypoxaemia (3000m). Aerospace Medicine and Human Performance, 88 (10), pp. 918-923.

    https://doi.org/10.3357/AMHP.4761.2017

  • Matu J; O'Hara J; Hill N; Clarke S; Boos C; Newman C; Holdsworth D; Ispoglou T; Duckworth L; Woods D (2017) Changes in appetite, energy intake, body composition and circulating ghrelin constituents during an incremental trekking ascent to high altitude. European Journal of Applied Physiology, 117 (9), pp. 1917-1928.

    https://doi.org/10.1007/s00421-017-3683-0

  • Shannon OM; Duckworth L; Barlow M; Deighton K; Matu J; Williams E; Woods D; Xie L; Stephan B; Siervo M (2017) Effects of dietary nitrate supplementation on physiological responses, cognitive function, and exercise performance at moderate and very-high simulated altitude. Frontiers in Physiology, 8

    https://doi.org/10.3389/fphys.2017.00401

  • Boos C; Vincent E; Mellor A; Woods D; Newman C; Cruttenden R; Barlow M; Cooke M; Deighton K; Scott P (2017) The effect of high altitude on central blood pressure and arterial stiffness. Journal of Human Hypertension, 31 pp. 715-719.

    https://doi.org/10.1038/jhh.2017.40

  • Black C; Till K; O'Hara JP; Davidson J; Jones B (2017) Top secret training data? External training loads of a cup winning English Super League rugby league team. International journal of Sports Science and Coaching, 13 (2), pp. 236-242.

    https://doi.org/10.1177/1747954117711094

  • Woods D; O'Hara J; Boos C; Hodkinson P; Tsakirides C; Hill N; Jose D; Hawkins A; Phillipson K; Hazlerigg A (2017) Markers of physiological stress during exercise under conditions of normoxia, normobaric hypoxia, hypobaric hypoxia and genuine high altitude. European Journal of Applied Physiology, 117 (5), pp. 893-900.

    https://doi.org/10.1007/s00421-017-3573-5

  • Mellor A; Bakker-Dyos J; OʼHara J; Woods DR; Holdsworth DA; Boos C (2017) Smartphone-Enabled Heart Rate Variability and Acute Mountain Sickness. Clinical Journal of Sport Medicine, 28 (1), pp. 76-81.

    https://doi.org/10.1097/JSM.0000000000000427

  • Shannon O; Barlow M; Duckworth L; Williams E; Wort G; Woods D; Siervo M; O'Hara JP (2017) Dietary nitrate supplementation enhances short but not longer duration running time-trial performance. European Journal of Applied Physiology, 117 (4), pp. 775-785.

    https://doi.org/10.1007/s00421-017-3580-6

  • Jones B; Till K; Roe G; O'Hara JP; Lees M; Barlow M; Hind K (2017) Six-year body composition change in male elite senior rugby league players. Journal of Sports Sciences, 36 (3), pp. 266-271.

    https://doi.org/10.1080/02640414.2017.1300313

  • O'Hara J; Woods D; Mellor A; Boos C; Gallagher L; Tsakirides C; Arjomandkhah N; Holdsworth D; Cooke CB; Morrison D (2017) A comparison of substrate oxidation during prolonged exercise in men at terrestrial altitude and normobaric normoxia following the coingestion of 13C glucose and 13C fructose. Physiological Reports, 5 (1), pp. e13101.

    https://doi.org/10.14814/phy2.13101

  • Wainwright B; Cooke CB; O'Hara J (2017) The validity and reliability of a sample of 10 Wattbike cycle ergometers. Journal of Sports Sciences, 35 (14), pp. 1451-1458.

    https://doi.org/10.1080/02640414.2016.1215495

  • Brightmore A; O'Hara J; Till K; Cobley S; Hubka T; Emmonds S; Cooke CB (2016) Movement and Physiological Demands of Australasian National Rugby League Referees. International Journal of Sports Physiology and Performance, 11 (8), pp. 1080-1087.

    https://doi.org/10.1123/ijspp.2015-0415

  • Shannon O; Duckworth L; Barlow M; Woods D; Lara J; Siervo M; O'Hara J (2016) Dietary nitrate supplementation enhances high-intensity running performance in moderate normobaric hypoxia, independent of aerobic fitness. Nitric Oxide, 59 pp. 63-70.

    https://doi.org/10.1016/j.niox.2016.08.001

  • Lees MJ; Oldroyd B; Jones B; Brightmore A; O'Hara J; Barlow M; Till K; Hind K (2016) Three-Compartment Body Composition Changes in Professional Rugby Union Players Over One Competitive Season : A Team and Individualized Approach. Journal of Clinical Densitometry, 20 (1), pp. 50-57.

    https://doi.org/10.1016/j.jocd.2016.04.010

  • Boos C; O'Hara J; Mellor A; Hodkinson PD; Tsakirides C; Reeve N; Gallagher L; Green ND; Woods DR (2016) A Four-Way Comparison of Cardiac Function with Normobaric Normoxia, Normobaric Hypoxia, Hypobaric Hypoxia and Genuine High Altitude. PLoS One, 11 (4),

    https://doi.org/10.1371/journal.pone.0152868

  • Boos C; Mellor A; O'Hara J; Tsakirides C; Woods DR (2016) The Effects of Sex on Cardiopulmonary Responses to Acute Normobaric Hypoxia. High Altitude Medicine and Biology, 17 (2), pp. 108-115.

    https://doi.org/10.1089/ham.2015.0114

  • Till K; Jones B; O'Hara J; Barlow M; Brightmore A; Lees M; Hind K (2016) Three-Compartment Body Composition in Academy and Senior Rugby League Players. International journal of sports physiology and performance, 11 (2), pp. 191-196.

    https://doi.org/10.1123/ijspp.2015-0048

  • Boos C; Bakker-Dyos J; Watchorn J; Woods DR; O'Hara J; Macconnachie L; Mellor A (2016) A comparison of two methods of heart rate variability assessment at high altitude. Clinical physiology and functional imaging, 37 pp. 582-587.

    https://doi.org/10.1111/cpf.12334

  • Jones B; Till K; Emmonds S; King RFGJ; Gray MP; Beggs CB; O'Hara J (2016) Hydration strategies of professional elite rugby league referees during super league matches. International Journal of Sports Science and Coaching, 11 (1), pp. 116-121.

    https://doi.org/10.1177/1747954115624811

  • Emmonds S; O'Hara J; Till K; Jones B; Brightmore A; Cooke CB (2015) Physiological and Movement Demands of Rugby League Referees: Influence on Penalty Accuracy. Journal of strength and conditioning research / National Strength & Conditioning Association, 29 (12), pp. 3367-3374.

    https://doi.org/10.1519/jsc.0000000000001002

  • Shah NM; Hussain S; Cooke M; O'Hara J; Mellor A (2015) Wilderness medicine at high altitude: recent developments in the field. Open access journal of sports medicine, 6 pp. 319-328.

    https://doi.org/10.2147/OAJSM.S89856

  • Ispoglou T; OʼKelly D; Angelopoulou A; Bargh MJ; O'Hara J; Duckworth LC (2015) Mouth Rinsing With Carbohydrate Solutions at the Postprandial State Fail to Improve Performance During Simulated Cycling Time Trials. Journal of strength and conditioning research / National Strength & Conditioning Association, 29 (8), pp. 2316-2325.

    https://doi.org/10.1519/jsc.0000000000000882

  • Duckworth LC; Backhouse SH; O'Hara J; Stevenson EJ (2015) Effect of Galactose Ingestion Before and During Exercise on Substrate Oxidation, Postexercise Satiety, and Subsequent Energy Intake in Females. Journal of the American College of Nutrition, 35 (1), pp. 1-12.

    https://doi.org/10.1080/07315724.2014.994790

  • Jones BL; O'Hara J; Till K; King RF (2015) Dehydration and hyponatremia in professional rugby union players: a cohort study observing english premiership rugby union players during match play, field, and gym training in cool environmental conditions. Journal of strength and conditioning research / National Strength & Conditioning Association, 29 (1), pp. 107-115.

    https://doi.org/10.1519/jsc.0000000000000620

  • O'Hara J; Carroll S; Cooke CB; King RF (2014) The effect of pre-exercise galactose and glucose ingestion on high-intensity endurance cycling. Journal of strength and conditioning research / National Strength & Conditioning Association, 28 (8), pp. 2145-2153.

    https://doi.org/10.1519/jsc.0000000000000372

  • Mellor AJ; Woods DR; O'Hara JP; Howley M; Watchorn J; Boos C (2014) Rating of Perceived Exertion and Acute Mountain Sickness during a High Altitude Trek. Aviation, Space, and Environmental Medicine

  • Mellor A; Boos C; Holdsworth D; Begley J; Hall D; Lumley A; Burnett A; Hawkins A; O'Hara JP; Ball S (2014) Cardiac biomarkers at high altitude. High Altitude Medicine and Biology

  • Boos CJ; Holdsworth DA; Hall DP; Mellor A; O'Hara J; Woods DR (2014) Comparison of two methods of assessing total body water at sea level and increasing high altitude. Clinical Physiology and Functional Imaging, 34 (6), pp. 478-484.

    https://doi.org/10.1111/cpf.12121

  • Woods DR; Mellor A; Begley J; Stacey M; O'Hara J; Hawkins A; Yarker J; Foxen S; Smith C; Boos C (2013) Brain natriuretic peptide and NT-proBNP levels reflect pulmonary artery systolic pressure in trekkers at high altitude. Physiological research / Academia Scientiarum Bohemoslovaca, 62 (6), pp. 597-603.

  • Detko E; O'Hara JP; Thelwall PE; Smith FE; Jakovljevic DG; King RF; Trenell MI (2013) Liver and muscle glycogen repletion using 13C magnetic resonance spectroscopy following ingestion of maltodextrin, galactose, protein and amino acids. The British Journal of Nutrition: an international journal of nutritional science, 110 (5), pp. 848-855.

    https://doi.org/10.1017/S0007114512005818

  • O'Hara J; Brightmore A; Till K; Mitchell I; Cummings S; Cooke CB (2013) Evaluation of movement and physiological demands of rugby league referees using global positioning systems tracking. International journal of sports medicine, 34 (9), pp. 825-831.

    https://doi.org/10.1055/s-0033-1333694

  • Mellor A; Boos C; Stacey M; Hooper T; Smith C; Begley J; Yarker J; Piper R; O'Hara J; King R (2013) Neutrophil gelatinase-associated lipocalin: its response to hypoxia and association with acute mountain sickness. Disease markers, 35 (5), pp. 537-542.

    https://doi.org/10.1155/2013/601214

  • King RFG (2013) Neutrophil gelatinase-associated lipocalin: its response to hypoxia and association with acute mountain sickness. Disease Markers, 35 (5), pp. 537-542.

    https://doi.org/10.1155/2013/601214

  • O'Hara J; Carroll S; Cooke CB; Morrison DJ; Preston T; King RF (2012) Preexercise galactose and glucose ingestion on fuel use during exercise. Medicine and science in sports and exercise, 44 (10), pp. 1958-1967.

    https://doi.org/10.1249/MSS.0b013e318258bf85

  • Fearnley D; Sutton L; O'Hara J; Brightmore A; King R; Cooke CB (2012) Case study of a female ocean racer: prerace preparation and nutritional intake during the Vendee Globe 2008. International journal of sport nutrition and exercise metabolism, 22 (3), pp. 212-219.

  • O'Hara J; Thomas A; Seims A; Cooke CB; King RF (2012) Reliability of a high-intensity endurance cycling test. International journal of sports medicine, 33 (1), pp. 18-25.

    https://doi.org/10.1055/s-0031-1284340

  • Morrison DJ; O'Hara JP; King RF; Preston T (2011) Quantitation of plasma 13C-galactose and 13C-glucose during exercise by liquid chromatography/isotope ratio mass spectrometry. Rapid Commun Mass Spectrom, 25 (17), pp. 2484-2488.

    https://doi.org/10.1002/rcm.5139

  • Morrison DJ; O'Hara JP; King RFGJ; Preston T (2011) Quantitation of Plasma 13C Galactose and 13C Glucose During Exercise by Liquid Chromatography Isotope Ratio Mass Spectrometry. Rapid Communications in Mass Spectrometry, 25 (17), pp. 2484-2488.

    https://doi.org/10.1002/rcm.5139

  • Harley JA; Hind K; O'Hara J (2011) Three-compartment body composition changes in elite rugby league players during a super league season, measured by dual-energy X-ray absorptiometry. Journal of strength and conditioning research / National Strength & Conditioning Association, 25 (4), pp. 1024-1029.

    https://doi.org/10.1519/JSC.0b013e3181cc21fb

  • O'Hara JP; Jones BL; Tsakirides C; Carroll S; Cooke CB; King RF (2010) Hydration status of rugby league players during home match play throughout the 2008 Super League season. Applied Physiology, Nutrition and Metabolism, 35 (6), pp. 790-796.

    https://doi.org/10.1139/H10-077

  • Till K; Cobley S; Wattie N; O'Hara J; Cooke CB; Chapman C (2010) The prevalence, influential factors and mechanisms of relative age effects in UK Rugby League. Scandinavian journal of medicine & science in sports, 20 (2), pp. 320-329.

    https://doi.org/10.1111/j.1600-0838.2009.00884.x

  • Harley JA; Hind K; O'Hara JP; Gross A (2009) Validation of the skin-fold thickness method and air displacement plethysmography with dual energy X-ray absorptiometry for the estimation of % body fat in professional male rugby football league players. International Journal of Body Composition Research, 7 (1), pp. 7-14.

  • Harley J; Hind K; O'Hara J; Gross A (2009) Validation of the skin-fold thickness method and air displacement plethysmography with dual energy X-ray absorptiometry, for the estimation of percent body fat in professional male rugby league players. International Journal of Body Composition Research, 7 (1), pp. 7-15.

  • Psycharakis SG; Cooke CB; Paradisis GP; O'Hara J; Phillips G (2008) Analysis of Selected Kinematic and Physiological Performance Determinants During Incremental Testing in Elite Swimmers. Journal of Strength and Conditioning Research, 22 (3), pp. 951-957.

    https://doi.org/10.1519/JSC.0b013e31816a6364

  • King RFGJ; Cooke C; Carroll S; O'Hara J (2008) Estimating changes in hydration status from changes in body mass: Considerations regarding metabolic water and glycogen storage. Journal of Sports Sciences, 26 (12), pp. 1361-1363.

    https://doi.org/10.1080/02640410802192768

  • Theodorou AS; Havenetidis K; Zanker CL; O'Hara JP; King RFGJ; Hood C; Paradisis G; Cooke CB (2005) Effects of Acute Creatine Loading With or Without Carbohydrate on Repeated Bouts of Maximal Swimming in High-Performance Swimmers. The Journal of Strength and Conditioning Research, 19 (2), pp. 265-265.

    https://doi.org/10.1519/15314.1

  • Cooke C eds. Cooke CB; Bunting D; O'Hara JP (2010) Mountaineering: Training and Preparation. Champaign: Illinois: Human Kinetics.