Alexander C. Stahn

Dr. Alexander Stahn
Assistant Professor in the Perelman School of Medicine at the University of Pennsylvania (USA)

Center for Space Medicine and Extreme Environments Berlin
+49 (0)30 450 528 553
Email Me

Alexander C. Stahn is an Assistant Professor in the Perelman School of Medicine at the University of Pennsylvania School of Medicine. He obtained his undergraduate and graduate degrees from Freie Universität Berlin, Germany, after which her worked as a Research Assistant at the University of Stellenbosch, Cape Town,  from 2003 to 2005. In 2008 he obtained his doctoral degree at Charité – Universitätsmedizin Berlin, Germany. He then assumed the position as a Research Associate at the Karlsruhe Institute of Technology (KIT), Germany, where he was awarded a Young Investigator Grant (YIG) to set up an independent research group in studying the effects of exercise on cognition and brain plasticity. In 2009 he returned to Charité to work as a Research Associate at Charité, where he was promoted to Deputy Laboratory Head at the Center for Space Medicine and Extreme Environments in 2014. In August 2016 he was appointed Assistant Professor of Medical Science in Psychiatry in the Perelman School of Medicine at the University of Pennsylvania (USA). His primary research focuses on the effects of environmental stressors on hippocampal plasticity and spatial cognition.

Research focus

  • Effects of spaceflight and environmental stressors (e.g., social isolation) on brain changes, cognitive performance and mental well-being
  • Hippocampal plasticity and spatial cognition in extreme environments
  • Effectiveness of preventive measures to mitigate negative neurobehavioral risks during spaceflight
  • Applying knowledge from space medicine to aging research on Earth

Current developments

  • His recent work includes the development of virtual reality system to augment sensory stimulation during isolation and confinementusing the “Overview Effect” experienced by astronauts when they see Earth from space.
  • Together with Dr. Mathias Stangl, he investigates the effects of isolation and confinement as well as spaceflight on grid cell firing patterns in the entorhinal cortex.
  • His experiment “HypoCampus”, investigating the effects of long-duration spaceflight on hippocampal plasticity and spatial cognitionis expected to be implemented on the International Space Station (ISS) in 2021. This experiment was also selected as part of NASA’s integrated 1-year missions on ISS, which will establish the dose-response relationship between and 2-month, 6-month and 12-month missions on ISS on brain plasticity and spatial cognition.
  • Currently, he is also investigating the effects of artificial gravity on brain plasticity during long-duration bed rest in a NASA sponsored study.
  • As part of a NASA Specialized Center for Research (Director: David F. Dinges), he is also Site-PI of the project investigating biomarkers of resilience during overwintering at Neumayer III station in Antarctica.

Research Projects

Principal Investigator

  • DLR/ESA/NASA (PI): Brain Changes and Spatial Navigation after Long-Duration Isolation and Confinement and the Significance of Virtual Earthgazing to Augment Sensory Stimulation
  • DLR/ESA/NASA (PI): HypoCampus in Integrated 1-Year Mission Project (i1YMP): Spatial Cognition and Hippocampal Plasticity During Long-Duration Low-Earth Orbit Missions: HypoCampus in i1YMP
  • NASA (PI): Hyper.Campus – Effects of Artificial Gravity on Structural and Functional Plasticity During
  • Head-Down Tilt Bed Rest
  • NASA (PI Antarctic Site): NASA Specialized Center of Research (NSCOR) for Evaluating Risk Factors and Biomarkers for Adaptation and Resilience to Spaceflight: Emotional Valence and Social Processes in ICC/ICE Environments (Director: David F. Dinges)
  • NASA/DLR (PI): Neuroplasticity in HERA – Structural and Functional Changes in Hippocampal Plasticity after Isolation and Its Behavioral Significance for Long Duration Space Exploration Missions
  • ESA/DLR (PI): Impact of Long-Duration Spaceflight on Hippocampal Volume and Visuo-Spatial Memory
  • ESA/DLR (PI): Effects of Parabolic Flight on Spatial Cognition and Hippocampal Plasticity
  • ESA/DLR (PI): Executive Control Functions and their Neurophysiologic Mechanisms During Head-Down-Tilt Bed Rest
  • ESA/DLR (PI): Impact of Bed Rest on Cognitive Performance and its Mechanisms: Interactions between Central Inflammatory Responses, Autonomic Nervous Control, and Brain Structure and Function


  • NASA (Co-I): Standardized Behavioral Measures for Detecting Behavioral Health Risks during Exploration
  • Missions (PI: David F. Dinges)
  • NASA (Co-I): Hybrid Training – A Sensory Stimulation Countermeasure for Long Duration Space
  • Exploration Missions (PI: Mathias Basner)
  • TRISH (Co-I): Evaluation of SmartSleep Technology for Improving the Efficiency and Restorative Quality of Sleep in Healthy Adults in Order to Mitigate Cognitive Performance Deficits Due to Sleep Restriction and Emergency Awakenings (PI: David F. Dinges)
  • TRISH (Co-I): Advanced Algorithms for the Prediction of Adverse Cognitive and Behavioral Conditions in Space (PI: Mathias Basner)
  • NASA (Consultant): Neurobehavioral Biomarkers Performance/Pathway for Central Nervous System (CNS) Radiation/Performance Data Mining (PI: Rajeev I. Desai)
  • NASA (Co-I): Bed Rest Combined with 0.5% CO2 as a Spaceflight Analog to Study Neurocognitive Changes: Extent, Longevity, and Neural Bases (PI: Rachel Seidler)
  • ESA/DLR (Co-I): Evaluation of Circadian Rhythm Alterations by Functional Biomarkers during Winter Over at Concordia (PI: Martina Maggioni)
  • ESA/DLR (Co-PI): Circadian Rhythms: Core Temperature and Circadian Rhythms in Humans During Long-term Spaceflights (PI: Hanns-Christian Gunga)


  • Mathias Basner, Dept. Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA
  • Stephane Besnard, Centre hospitalier universitaire de Caen Normandie, Caen, France
  • Pierre Denise, Mobilités: Attention, Orientation et Chronobiologie, U 1075 COMETE, Université de Caen Normandie, Caen, France
  • David F. Dinges, Dept. Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA
  • Elena Fomina, Institute of Biomedical Problems (IBMP) of the Russian Academy of Sciences, Moscow, Russia
  • Tom Hartley, Dept. of Psychology, University of York, Heslington, York, United Kingdom
  • Simone Kühn, Max-Planck-Institute for Human Development, Berlin, Germany
  • Bernhard Riecke, School of Interactive Arts and Technology (SIAT), Simon Fraser University, Surrey, Canada
  • Martin Riemer, Department of Experimental Psychology, University of Groningen, Groningen, the Netherlands
  • Mathias Stangl, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles (UCLA), Los Angeles, USA
  • Thomas Wolbers, Aging and Cognition Research Group, German Center for Neurodegenerative Diseases (DZNE), Site Magdeburg, Germany


  • Young Investigator Award, Society of Brain Mapping & Therapeutics (SBMT), 2017
  • Institute for Experimental Psychiatry Research Foundation Award, 2016
  • German Academic Exchange Service (DAAD), International Travel Award, 2011
  • Young Investigator Grant, Karlsruhe Institute of Technology, 2009
  • BASES Elsevier Oral Presentation Award, British Association of Sport and Exercise Sciences, 2006
  • Harry Crossley Award, University of Stellenbosch, 2005
  • Elsa Neumann (Nafög) Award, Berlin Senate of Education, Research and Science, 2004
  • German Research Foundation, DFG International Travel Award, 2004

Board Membership

  • Review Editor Frontiers in Physiology section “Environmental, Aviation and Space Physiology”, since 2018
  • Expert member of the National Aeronautics and Space Administration (NASA) and European Space Agency (ESA) team to define standardized behavioral, physiological and performance parameters for isolation and confined environments, 2018-2019
  • Subject Matter Expert for Mars Expedition Task Analysis, National Aeronautics and Space Administration (NASA), 2016
  • Executive board member of the German Society for Aviation and Space Medicine, 2014-2016
  • Organizer, 6th International Congress of Medicine in Space and Extreme Environments (ICMS)
  • Expert member of the ESA Isolation Steering Committee (supporting the definition of ESA’s strategy for future isolation and confinement studies), 2015-2016
  • Expert member of the study Group 2.15 (Immersion Model) of the International Academy of Astronautics (IAA)
  • Scientific Committee Member, DLR :envihab German Human Physiology Workshop, 2016-2017

Selected Bibliography

Stahn, A.C. & Kühn, S. Extreme environments for understanding brain and cognition. Trends in Cognitive Sciences. In Press.

Brauns, K., Friedl-Werner, A., Gunga, H.-C., & Stahn, A. C. (2021). Effects of two months of bed rest and antioxidant supplementation on attentional processing. Cortex, 141, 81-93.

Stahn, A.C. & Kühn, S. Brains in space: the importance of understanding the impact of long-duration spaceflight on spatial cognition and its neural circuitry (2021). Cognitive Processes 22(Suppl 1): 105-114.

Mendt, Stefan, Brauns, K., Friedl-Werner, A., Belavy, D. L., Steinach, M., Schlabs, T., Werner, A., Gunga, H.-C., & Stahn, A. C. (2021). Long-Term Bed Rest Delays the Circadian Phase of Core Body TemperatureFrontiers in Physiology12, 658707.

Friedl-Werner, A., Machado, M.-L., Balestra, C., Liegard, Y., Philoxene, B., Brauns, K., Stahn, A. C., Hitier, M., & Besnard, S. (2021). Impaired attentional processing during parabolic flightFrontiers in Physiology12, 597

Mendt, Stefan, Gunga, H. C., Felsenberg, D., Belavy, D. L., Steinach, M.*, & Stahn, A. C.(2021). Regular exercise counteracts circadian shifts in core body temperature during long- duration bed rest. npj Microgravity7(1), 1–6.

Brauns, K., Friedl-Werner, A., Maggioni, M. A., Gunga, H. C., & Stahn, A. C. (2021). Head-Down Tilt Position, but Not the Duration of Bed Rest Affects Resting State Electrocortical Activity. Frontiers in Physiology12, 638669.

Basner, M., Dinges, D. F., Howard, K., Moore, T. M., Gur, R. C., Mühl, C., & Stahn, A. C. (2021). Continuous and Intermittent Artificial Gravity as a Countermeasure to the Cognitive Effects of 60 Days of Head-Down Tilt Bed RestFrontiers in Physiology12, 643854. 

Basner, M.*Stahn, A. C.*, Nasrini, J., Dinges, D. F., Moore, T. M., Gur, R. C., Mühl, C., Macias, B. R., & Laurie, S. S. (2021). Effects of head-down tilt bed rest plus elevated CO2 on cognitive performance. Journal of Applied Physiology130(4), 1235–1246.

Friedl-Werner, A., Brauns, K., Gunga, H.C., Kühn, S. & A.C. Stahn. Exercise-induced changes in brain activity during memory encoding and retrieval after long-term bed rest. NeuroImage 223: 117359, 2020

Roberts, D., Stahn, A.C., Seidler, R., Wuyts, F. Towards understanding the effects of spaceflight on the brain. Lancet Neurology, 19(10): 808, 2020

Stahn AC, Riemer M, Wolbers T, Werner A, Brauns K, Besnard S, Denise P, Kühn S, Gunga HC. Spatial Updating Depends on Gravity. Front Neural Circuits. 2020 Jun 5;14:20.

Stahn AC, Maggioni MA, Gunga HC, Terblanche E. Combined protein and calcium β-hydroxy-β-methylbutyrate induced gains in leg fat free mass: a double-blinded, placebo-controlled study. J Int Soc Sports Nutr. 2020 Mar 12;17(1):16.

Stahn, A., Gunga, H.C., Kohlberg, E., Gallinat, J., Kühn, S., Brain Changes in Response to Long Antarctic Expeditions. New England Journal of Medicine 381; 23, 2019 (DOI: 10.1056/NEJMc1904905)

Brauns K., Werner A., Gunga H.C., Maggioni M.A.M., Dinges D.F., Stahn, A. Electrocortical Evidence for Impaired Affective Picture Processing after Long-Term Immobilization. Nature Sci Rep 9, 16610, 2019.

Strewe C., Moser D., Buchheim J.I., Gunga H.C., Stahn A., Crucian B.E., Fiedel B., Bauer H., Gössmann-Lang P., Thieme D., Kohlberg E., Choukèr A., Feuerecker M. Sex differences in stress and immune responses during confinement in Antarctica. Biol Sex Differ. 10(1):20, 2019.

Trautwein S., Barisch-Fritz B., Scharpf A., Bossers W., Meinzer M., Steib S., Stein T., Bös K., Stahn A., Niessner C., Altmann S., Wittelsberger R., Woll A. Recommendations for assessing motor performance in individuals with dementia: suggestions of an expert panel – a qualitative approach. Eur Rev Aging Phys Act. 16:5, 2019.

Martina, M.A., Castiglioni, P., Merati, G., Brauns,K., Gunga, H.C., Mendt, S., Opatz, O.S., Rundfeldt, L.C., Steinach, M. Werner, A., Stahn, A.: High-Intensity Exercise Mitigates Cardiovascular Deconditioning During Long-Duration Bed Rest. Front Physiol. 9: 1553, 2018

Opatz, S.O., Nordine, M., Habazettl,H., Ganse, B., Petricek, J., Dosel, P., Stahn, A., Steinach, M., Gunga, H.C., Maggioni, M.A.: Limb Skin Temperature as a Tool to Predict Orthostatic Instability. Front Physiol. 9: 1241, 2018

Stahn, A.,  Werner, A.,  Opatz, O.,  Maggioni, M. A.,  Steinach, M.,  von Ahlefeld, V. W.,  Moore, A.,  Crucian, B. E.,  Smith, S. M.,  Zwart, S. R.,  Schlabs, T.,  Mendt, S.,  Trippel, T.,  Koralewski, E.,  Koch, J.,  Chouker, A.,  Reitz, G.,  Shang, P.,  Rocker, L.,  Kirsch, K. A.,  Gunga, H. C.: Increased core body temperature in astronauts during long-duration space missions. Nature Sci Rep 7(1): 16180, 2017.

Mendt, S., Maggioni, M.A., Nordine, M., Steinach, M., Opatz, O., Belavý, D., Felsenberg, D., Koch, J., Shang, P., Gunga, H.C., and Stahn, ACircadian rhythms in bed rest: Monitoring core body temperature via heat-flux approach is superior to skin surface temperature. Chronobiol Int 34(5): 666-676, 2017.

Trippel, T.D., Lenk, J., Gunga, H.C., Doehner, W., von Haehling, S., Loncar, G., Edelmann, F., Pieske, B., Stahn, A., Duengen, H.D. Estimating fat mass in heart failure patient. Arch Med Sci Atheroscler Dis 2016; 1: e1–e12.

Villa, F., Magnani, A., Maggioni, M.A., Stahn, A., Rampichini, S., Merati, G., Castiglioni, P. Wearable Multi-Frequency and Multi-Segment Bioelectrical Impedance Spectroscopy for Unobtrusively Tracking Body Fluid Shifts during Physical Activity in Real-Field Applications: A Preliminary Study. Sensors 16(5), 673, 2016.

Steinach, M., Kohlberg, E.; Maggioni, M.A.; Mendt, S., Opatz, O., Stahn, A., Tiedemann, J., Gunga, H.C. Sleep Quality Changes during Overwintering at the German Antarctic Stations Neumayer II and III: the Gender Factor. Plos One. 11(2): e0150099. doi:10.1371/journal.pone.0150099.

Steinach, M., Kohlberg, E.; Maggioni, M.A.; Mendt, S., Opatz, O., Stahn, A., Tiedemann, J., Gunga, H.C. Changes of 25-OH-Vitamin D during Overwintering at the German Antarctic Stations Neumayer II and III. Plos One. 10(12):e0144130. doi: 10.1371/journal.pone.014413

Habazettl, H., Stahn, A., Nitsche, A., Nordine, M., Pries, A., Gunga, H.C., Opatz, O. Microvascular responses to (hyper-)gravitational stress by short-arm human centrifuge: arteriolar vasoconstriction and venous pooling.European Journal of Applied Physiology. 116(1):57-65, 2016. doi: 10.1007/s00421-015-3241-6

Nordine M., Maggioni, M.A., Stahn, A., Mendt, S. Brauns, K., Gunga. H.C., Habazettl, H. Nitsche, A., Opatz, O. Form influences function: anthropometry and orthostatic stability during sustained acceleration in a short arm human centrifuge. Acta Astronautica 115: 138-146, 2015.

Stahn, A., Gunga. H.-C. Methodology. In: Human Physiology in Extreme Environments. New York: Elsevier, pp. 39-75, 2014.

Schmidt, S.C.E., Krell, J., Bös, K., Stahn, AGeneral sports participation rather than amount or intensity is related to body composition among healthy adolescents. International Journal of Sports Science, 3(6): 217-223, 2013.

Stahn, A., Terblanche, E., Gunga, H.C. Selected Applications of Bioelectrical Impedance Analysis: Body Fluids, Blood Volume, Cell and Fat Mass. The Handbook of Anthropometry: Physical Measures of Human Form in Health and Disease. New York: Springer, pp. 415-440, 2013.

Schlabs, T., Rosales-Velderrain, A., Ruckstuhl. H., Stahn, A., Hargens, A.R. Comparison of cardiovascular and biomechanical parameters of supine lower body negative pressure and upright lower body positive pressure to simulate activity in 1/6 G and 3/8 G. Journal of Applied Physiology 115(2): 275-84, 2013.

Stahn, A., Terblanche, E., Gunga, H.C. Use of Bioelectrical Impedance: General Overview and Principles. In: Preedy VR, editor. Handbook of Anthropometry: Physical Measures of Human Form in Health and Disease.New York: Springer, pp. 49-90, 2013.

Opatz, O., Trippel T., Lochner, A., Werner, A., Stahn, A., Steinach, M., Lenk, J., Kuppe, H., Gunga, H.C. Temporal and spatial dispersion of human body temperature during deep hypothermia. British Journal of Anaesthesia 111(5): 768-75, 2013.

Schmidt, S.,  Krell, J.,  Bos, K.,  Stahn, A.: General Sports Participation rather than Amount or Intensity is Related to Body Composition among Healthy Adolescents. International Journal of Sports Science 3(6): 217-223, 2011.

Gunga, H.C., Steinach, M., Kirsch, K., Stahn, A., Werner, A. Weltraummedizin und -Biologie. In: Ley W, Wittmann K, Hallmann W, editors. Handbuch Der Raumfahrttechnik. München: Hanser Verlag, pp. 583-597, 2011.

Ganse, B., Stahn, A., Stoinski, S., Suthau, T., and Gunga, H.C. Chapter 7, Body mass, thermoregulation and cardiovascular of large sauropods. In: Sander M, editors. The Life of Giants. Bloomington: Indiana University Press, 2010, pp. 105-115.

Gunga, H.C., Werner, A., Stahn, A., Steinach, M., Schlabs, T., Koralewski, E., Kunz, D., Belavy, D.L., Felsenberg, D., Sattler, F., Koch, J. The Double Sensor-a Non-Invasive Device to Continuously Monitor Core Temperature in Humans on Earth and in Space. Respiratory Physiology & Neurobiology 169: S63-S68, 2009.

Stahn, A., Strobel, G., Terblanche, E. VO2max Prediction from Multi-Frequency Bioelectrical Impedance Analysis. Physiological Measurement 29: 193-203, 2008.

Stahn, A., Terblanche, E., Strobel, G. Modeling Upper and Lower Limb Muscle Volume by Bioelectrical Impedance Analysis. Journal of Applied Physiology 103: 1428-1435, 2007.

Stahn, A., Terblanche, E., Grunert, S., Strobel, G. Estimation of Maximal Oxygen Uptake by Bioelectrical Impedance Analysis. European Journal of Applied Physiology 96: 265-273, 2006.

Stahn, A., Terblanche, E., Strobel, G. Monitoring Exercise-Induced Fluid Shifts by Segmental Bioelectrical Impedance Analysis. In: Marfell-Jones M, Stewart A, Olds T, editors. Kinanthropometry IX. London and New York: Routledge, pp. 65-94, 2006.