Aaltonen S, Leskinen T, Morris T, Alen M, Kaprio J, Liukkonen J et al (2012). Motives for and barriers to physical activity in twin pairs discordant for leisure time physical activity for 30 years. Int J Sports Med 33: 157–163.
Aberg MAI, Pedersen NL, Torén K, Svartengren M, Bäckstrand B, Johnsson T et al (2009). Cardiovascular fitness is associated with cognition in young adulthood. Proc Natl Acad Sci USA 106: 20906–20911.
Arida RM, Gomes da Silva S, de Almeida AA, Cavalheiro EA, Zavala-Tecuapetla C, Brand S et al (2015). Differential effects of exercise on brain opioid receptor binding and activation in rats. J Neurochem 132: 206–217.
Bartlett JD, Close GL, MacLaren DPM, Gregson W, Drust B, Morton JP (2011). High-intensity interval running is perceived to be more enjoyable than moderate-intensity continuous exercise: implications for exercise adherence. J Sports Sci 29: 547–553.
Boecker H, Sprenger T, Spilker ME, Henriksen G, Koppenhoefer M, Wagner KJ et al (2008). The runner’s high: opioidergic mechanisms in the human brain. Cereb Cortex 18: 2523–2531.
Bradley MM, Lang PJ (1994). Measuring emotion: the self-assessment manikin and the semantic differential. J Behav Ther Exp Psychiatry 25: 49–59.
Chartoff EH, Connery HS (2014). It’s MORe exciting than mu: crosstalk between mu opioid receptors and glutamatergic transmission in the mesolimbic dopamine system. Front Pharmacol 5: 116.
Colasanti A, Searle GE, Long CJ, Hill SP, Reiley RR, Quelch D et al (2012). Endogenous opioid release in the human brain reward system induced by acute amphetamine administration. Biol Psychiatry 72: 371–377.
Colcombe SJ, Kramer AF, Erickson KI, Scalf P, McAuley E, Cohen NJ et al (2004). Cardiovascular fitness, cortical plasticity, and aging. Proc Natl Acad Sci USA 101: 3316–3321.
de Oliveira MSR, da Silva Fernandes MJ, Scorza FA, Persike DS, Scorza CA, da Ponte JB et al (2010). Acute and chronic exercise modulates the expression of MOR opioid receptors in the hippocampal formation of rats. Brain Res Bull 83: 278–283.
Decker ES, Ekkekakis P (2017). More efficient, perhaps, but at what price? Pleasure and enjoyment responses to high-intensity interval exercise in low-active women with obesity. Psychol Sport Exerc 28: 1–10.
Dietrich A, McDaniel WF (2004). Endocannabinoids and exercise. Br J Sports Med 38: 536–541.
Dishman RK, O’Connor PJ (2009). Lessons in exercise neurobiology: the case of endorphins. Ment Health Phys Act 2: 4–9.
Duerden EG, Albanese M-C (2013). Localization of pain-related brain activation: a meta-analysis of neuroimaging data. Hum Brain Mapp 34: 109–149.
Ekkekakis P, Parfitt G, Petruzzello SJ (2011). The pleasure and displeasure people feel when they exercise at different intensities. port Med 41: 641–671.
Endres CJ, Bencherif B, Hilton J, Madar I, Frost JJ (2003). Quantification of brain mu-opioid receptors with [11C]carfentanil: reference-tissue methods. Nucl Med Biol 30: 177–186.
Frost JJ, Douglass KH, Mayberg HS, Dannals RF, Links JM, Wilson AA et al (1989). Multicompartmental analysis of [11C]-carfentanil binding to opiate receptors in humans measured by positron emission tomography. J Cereb Blood Flow Metab 9: 398–409.
Fuss J, Steinle J, Bindila L, Auer MK, Kirchherr H, Lutz B et al (2015). A runner’s high depends on cannabinoid receptors in mice. Proc Natl Acad Sci USA 112: 13105–13108.
Goldfarb AH, Jamurtas AZ (1997). Beta-endorphin response to exercise. An update. Sports Med 24: 8–16.
Gunn RN, Lammertsma AA, Hume SP, Cunningham VJ (1997). Parametric imaging of ligand-receptor binding in PET using a simplified reference region model. Neuroimage 6: 279–287.
Haber SN, Knutson B (2010). The reward circuit: linking primate anatomy and human imaging. Neuropsychopharmacology 35: 4–26.
Hall EE, Ekkekakis P, Petruzzello SJ (2002). The affective beneficence of vigorous exercise revisited. Br J Health Psychol 7: 47–66.
Heijnen S, Hommel B, Kibele A, Colzato LS (2015). Neuromodulation of aerobic exercise-a review. Front Psychol 6: 1890.
Henriksen G, Willoch F (2008). Imaging of opioid receptors in the central nervous system. Brain 131: 1171–1196.
Hirvonen J, Aalto S, Hagelberg N, Maksimow A, Ingman K, Oikonen V et al (2009). Measurement of central mu-opioid receptor binding in vivo with PET and [11C]carfentanil: a test-retest study in healthy subjects. Eur J Nucl Med Mol Imaging 36: 275–286.
Jung ME, Bourne JE, Little JP (2014). Where Does HIT Fit? An examination of the affective response to high-intensity intervals in comparison to continuous moderate- and continuous vigorous-intensity exercise in the exercise intensity-affect continuum. PLoS ONE 9: e114541.
Kanning M, Schlicht W (2010). Be active and become happy: an ecological momentary assessment of physical activity and mood. J Sport Exerc Psychol 32: 253–261.
Kilpatrick M, Kraemer R, Bartholomew J, Acevedo E, Jarreau D (2007). Affective responses to exercise are dependent on intensity rather than total work. Med Sci Sports Exerc 39: 1417–1422.
Leknes S, Tracey I (2008). A common neurobiology for pain and pleasure. Nat Rev Neurosci 9: 314–320.
Liberzon I, Zubieta JK, Fig LM, Phan KL, Koeppe RA, Taylor SF (2002). μ-Opioid receptors and limbic responses to aversive emotional stimuli. Proc Natl Acad Sci 99: 7084–7089.
Mazzeschi C, Piana N, Capezzali D, Mommi A, Aiello C, Gatti M et al (2014). The impact of strenuous group physical activity on mood states, personal views, body composition, and markers of myocardial damage in overweight/obese adults: the ‘Step-by-step Italy’s coast to coast’ trek. Biomed Res Int 2014: 854129.
Mick I, Myers J, Ramos AC, Stokes PRA, Erritzoe D, Colasanti A et al (2016). Blunted endogenous opioid release following an oral amphetamine challenge in pathological gamblers. Neuropsychopharmacology 41: 1742–1750.
Mick I, Myers J, Stokes PRA, Erritzoe D, Colasanti A, Bowden-Jones H et al (2014). Amphetamine induced endogenous opioid release in the human brain detected with [11C]carfentanil PET: replication in an independent cohort. Int J Neuropsychopharmacol 17: 2069–2074.
Milanović Z, Sporiš G, Weston M (2015). Effectiveness of high-intensity interval training (HIT) and continuous endurance training for VO2max improvements: a systematic review and meta-analysis of controlled trials. Sports Med 45: 1469–1481.
Morgan WP (1985). Affective beneficence of vigorous physical activity. Med Sci Sports Exerc 17: 94–100.
Nummenmaa L, Tuominen L (2017). Opioid system and human emotions. Br J Pharmacol, doi:10.1111/bph.13812.
Oliveira BRR, Deslandes AC, Santos TM (2015). Differences in exercise intensity seems to influence the affective responses in self-selected and imposed exercise: a meta-analysis. Front Psychol 6: 1105.
Ramos JS, Dalleck LC, Tjonna AE, Beetham KS, Coombes JS (2015). The impact of high-intensity interval training versus moderate-intensity continuous training on vascular function: a systematic review and meta-analysis. Sports Med 45: 679–692.
Ruegsegger GN, Toedebusch RG, Will MJ, Booth FW (2015). Mu opioid receptor modulation in the nucleus accumbens lowers voluntary wheel running in rats bred for high running motivation. Neuropharmacology 97: 171–181.
Saanijoki T, Nummenmaa L, Eskelinen J-J, Savolainen AM, Vahlberg T, Kalliokoski KK et al (2015). Affective responses to repeated sessions of high-intensity interval training. Med Sci Sports Exerc 47: 2604–2611.
Saarimäki H, Gotsopoulos A, Jääskeläinen IP, Lampinen J, Vuilleumier P, Hari R et al (2016). Discrete neural signatures of basic emotions. Cereb Cortex 26: 2563–2573.
Schwarz L, Kindermann W (1992). Changes in beta-endorphin levels in response to aerobic and anaerobic exercise. Sport Med 13: 25–36.
Scott DJ, Stohler CS, Koeppe RA, Zubieta J-K (2007). Time-course of change in [11C]carfentanil and [11C]raclopride binding potential after a nonpharmacological challenge. Synapse 61: 707–714.
Scully D, Kremer J, Meade MM, Graham R, Dudgeon K (1998). Physical exercise and psychological well being: a critical review. Br J Sports Med 32: 111–120.
Sgherza AL, Axen K, Fain R, Hoffman RS, Dunbar CC, Haas F (2002). Effect of naloxone on perceived exertion and exercise capacity during maximal cycle ergometry. J Appl Physiol 93: 2023–2028.
Titeler M, Lyon RA, Kuhar MJ, Frost JF, Dannals RF, Leonhardt S et al (1989). Mu opiate receptors are selectively labelled by [3H]carfentanil in human and rat brain. Eur J Pharmacol 167: 221–228.
Trezza V, Damsteegt R, Achterberg EJM, Vanderschuren LJMJ (2011). Nucleus accumbens μ-opioid receptors mediate social reward. J Neurosci 31: 6362–6370.
Wahl P, Mathes S, Köhler K, Achtzehn S, Bloch W, Mester J (2013). Acute metabolic, hormonal, and psychological responses to different endurance training protocols. Horm Metab Res 45: 827–833.
Watson D, Clark LA, Tellegen A (1988). Development and validation of brief measures of positive and negative affect: the PANAS scales. J Pers Soc Psychol 54: 1063–1070.
Weston KS, Wisløff U, Coombes JS (2014). High-intensity interval training in patients with lifestyle-induced cardiometabolic disease: a systematic review and meta-analysis. Br J Sports Med 48: 1227–1234.
Yeung RR (1996). The acute effects of exercise on mood state. J Psychosom Res 40: 123–141.
Zubieta J-K, Smith YR, Bueller JA, Xu Y, Kilbourn MR, Jewett DM et al (2002). μ-opioid receptor-mediated antinociceptive responses differ in men and women. J Neurosci 22: 5100–5107.
Zubieta JK, Smith YR, Bueller JA, Xu Y, Kilbourn MR, Jewett DM et al (2001). Regional mu opioid receptor regulation of sensory and affective dimensions of pain. Science 293: 311–315.