The human body is an amazingly complicated machine, capable of adapting and responding to various stressors and environmental conditions. Even in extreme situations the body is able to adjust core physiological processes and systems to ensure optimal function, and ultimately, survival. When studying human physiological response the most basic measurements, such as ECG and respiration, can hold huge amounts of information. But, their value is much greater when integrated with other physiological measurements such as blood pressure, oxygen saturation and respiratory gas concentrations. However, accurate co-registration of physiological data is no trivial pursuit. Moreover, the complexity of such research endeavors is compounded when we venture out of traditional laboratory spaces and seek to study human response and adaptation in extreme environments. Sensors and systems must offer practical application and reliable data collection -- moreover, data storage and management is of critical importance. In this webinar sponsored by ADInstruments, Dr. Trevor Day, Associate Professor of Physiology at Mount Royal University in Calgary Alberta, shares his research on the effects of tilt, exercise and high altitude on respiratory sinus arrhythmia (RSA). These case studies serve as representations of more complex applications of human physiologic monitoring, in particular, his trek to Everest Base Camp where he and his research team monitored and tracked acclimatization in the context of high altitude hypoxia. During this expedition multiple physiological measures were recorded simultaneously on both rest and exercise days in order to test for signs of altitude sickness. Dr. Day shares his experiences from this exciting study and others conducted at his lab at Mount Royal to offer perspective regarding the importance of being able to record and integrate multiple data streams simultaneously.

1. Mountain Lab:
Studying the effects of stress and extreme
conditions on human physiology
A webinar discussing the effects of tilt, exercise and high altitude
on human cardiorespiratory and autonomic nervous systems, as
studied in traditional laboratory settings and on location at Everest
Base Camp.

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3. Mountain Lab:
Studying the effects of stress and extreme
conditions on human physiology
Dr. Trevor Day
Associate Professor of Physiology
Department of Biology
Faculty of Science and Technology
Mount Royal University
tday@mtroyal.ca

4. Acknowledgements
Trainees:
Jeff Baden B.Sc. M.Sc. Maria Abrosimova B.Sc.
Gary Saran B.Sc. Lauren Lavoie B.Sc.
Jamie Pfoh B.Sc. Christina Bruce B.Sc.
Kennedy Borle B.Sc. Andrea Linares
Rachelle Brandt B.Sc. Kartika Tjandra Ph.D.
Michael Tymko M.Sc. Rachel Skow M.Sc.
Lindsey Boulet B.Sc.
A special thank you to our research
participants, MRU Human Research
Ethics Board and Nepal Health
Research Council
Collaborators:
Funding
& Support:

5. Calgary, Alberta, Canada

6. Mount Royal University

7. Chemoreflex Control of Breathing
• Central respiratory chemoreflex
• Peripheral respiratory chemoreflex
• Central-peripheral chemoreceptor interaction
• Intermittent hypoxia
• High altitude hypoxia and acclimatization
Cerebral Blood Flow Regulation
• Cerebral autoregulation
• Cerebrovascular CO2 reactivity
• Neurovascular coupling
Hypovolemia and Tilt
• Cerebrovascular regulation
• Baroreflex responses
• Respiratory sinus arrhythmia (RSA)
MRU INTEGRATIVE Physiology lab
Department of Biology, Faculty of Science and Technology

8. Kidneys
Heart
Lungs
Brain
Stress Stress
Stress Stress

9. List of Acronyms
• ECG: Electrocardiogram
• HR: Heart rate
• BPM: beats per minute
• RSA: Respiratory sinus arrhythmia
• VTI: Inspired tidal volume (L)
• FVC: Forced vital capacity (L)
• MAP: Mean Arterial Pressure
(i.e., blood pressure; mm Hg)
• TCD: Transcranial Doppler ultrasound
(for brain blood flow)
• MCAv: Middle cerebral artery velocity
(using ultrasound; cm/s)
• Q: Cardiac output (L/min)
• V/Q: Ratio relating alveolar ventilation
and perfusion of the lung
• PETCO2: pressure of end-tidal CO2 (Torr)
• HUT and HDT: Head-up and head-down tilt

10. Novel Integrated Tilt
Table-Lower Body
Negative Pressure
Box (LBNP)
• Built by Michael Tymko (M.Sc.;
now PhD student UBC)
• Superimposes tilt and LBNP
stressors
• Tilt table allows HUT and HDT
• LBNP chamber creates a
negative pressure to
translocate blood volume
toward the lower body

11. 2014 Alberta Science and Technology (ASTech)
Young Innovator Award

12. Michael Tymko recently published an “instruction manual” on
constructing LBNP chambers (Nov 2016, In press).

13. “The effects of superimposed tilt and lower body negative pressure on anterior
and posterior cerebral circulations” Tymko et al., 2016

14. 2015 American Physiological Society ADInstruments Macknight
Early Career Innovative Educator Award
APS President David Pollock and Anthony Macknight
of ADI present the ADInstruments Macknight Early
Career Innovative Educator Award to Trevor A. Day

15. Respiratory Sinus
Arrhythmia (RSA)
• RSA is the normal
fluctuation of heart rate in
phase with the respiratory
cycle
• Inspiration = increase in HR
• Expiration = decrease in HR
• HR quantified from the
ECG
• The “peak-valley” of the
HR tracing quantifies RSA
magnitude

16. • These signals are
processed in ADI LabChart
Pro from analog inputs
• IHR from ECG
• MAP from a raw
finometer input
• MCAv mean from TCD
• VTI from respiratory flow
• PETCO2 from breath by
breath expired gas
analyzer
• Note that MAP and MCAv
fluctuate in phase with
RSA
RSA affects blood
pressure and brain
blood flow

17. Possible mechanisms underlying
Respiratory sinus arrhythmia (RSA)
RSA magnitude is thought to represent the dominance of parasympathetic
nervous system tone at rest.
Possible mechanisms include:
1. Firing of respiratory neurons impacting the firing of cardiac motor neurons in
the brainstem.
2. Stretch receptors in the lungs and chest wall.
3. Changes in blood pressure with breathing acting on arterial baroreceptors
(carotid and aortic sinus).
4. Changes in venous return and cardiac loading with breathing stimulating low
pressure receptors in the right atrium (Bainbridge reflex).

18. Respiratory Pump

19. Inspiration
Increased heart rate
Increased venous return
Increased right atrial pressure
Inhibition of medullary cardiac
neurons and vagal withdrawal
Stimulation of stretch receptors in
right atria and pulmonary artery

20. Expiration
Decreased heart rate
Decreased venous return
Decreased right atrial pressure
No inhibition of medullary cardiac
neurons and increased vagal tone
Less stimulation of stretch
receptors in right atria

21. Factors Modulating RSA Magnitude?
Tidal volume
Nervous system
activation
Blood gas
levels
Fitness level
Respiratory
frequency
Age RSA

22. Possible Utility of RSA?
RSA may increase
pulmonary gas
exchange efficiency
through improved
V/Q matching
Ventilation
Perfusion
Inspiration
HR and Q increase
Expiration
HR and Q decrease

23. Tilt Exercise Hypoxia

24. Tilt and blood volume distribution
• Tilt causes gravity-dependent
redistribution of blood volume
• Standing or HUT translocates up
to 1L of blood volume toward
the lower extremities
• HDT translocates blood into the
central cavity, increasing venous
return and cardiac loading Trendelenburg position

25. • Gelinas et al., 2012 Aviat
Space Environ Med
• Skow et al., 2013 Resp Physiol
Neurobiol
• Skow et al., 2014 Prog Brain
Res
• Tymko et al., 2015 Exp Physiol
We investigated the
effects of steady-state
tilt on respiratory and
cerebrovascular
regulation.
Previous tilt
studies in the lab

26. Baden et al., 2014 Aviat Space Environ Med
Case Report: 45 Degree Head Down Tilt

27. Case Report: 45 Degree Head Down Tilt
• Sinus arrhythmia
• Note the P waves
(red arrows)
• NOT pathological

28. Badenetal.,2014AviatSpaceEnvironMed

29. Experiment #1: Tilt and RSA
Aim:
To explore the relationship between superimposed gravity-
dependent and inspiration-dependent cardiac filling on RSA magnitude.
Hypothesis:
Superimposed gravity- and inspiration-dependent cardiac loading will
increase RSA magnitude in a synergistic fashion.

30. Methods
10%, 20%, 30%, 40%, and 50% of FVC
RANDOMIZED
RANDOMIZED
40o HDT
40o HUT
FVC (x3)
n=19

31. Analysis
• Peak-valley method
• Data from 5 of the most
accurate, consecutive
breaths
• Correlation between VTI
and RSA magnitude
• RSA magnitude plotted
against each targeted VTI (%
FVC)
• Linear regression of RSA
magnitude against VTI
• Slopes calculated to
quantify “RSA reactivity”
20%
FVC
40%
FVC
Abrosimova et al., Manuscript in Preparation

32. HUT; r = 0.64; P<0.001 HDT; r = 0.53; P<0.001
RSA magnitude is correlated with VTI
Abrosimova et al., Manuscript in Preparation

33. HUT=0.43 HDT=0.33R2=0.99 R2=0.99
P=0.02
“RSA reactivity” in response to increases in VTI is linear
Abrosimova et al., Manuscript in Preparation
Response slopes are tilt-dependent

34. Summary
• RSA magnitude increases linearly with
increases in VTI (“RSA reactivity”)
• RSA reactivity is not increased with HDT
• RSA reactivity is decreased in HDT, likely do to
sympathetic NS modulation
• Question: Can we test RSA reactivity during another
stressor where venous return is increased and the
sympathetic NS is activated?

35. Skeletal Muscle Pump

36. Aim:
To explore the relationship between superimposed exercise stress
(with skeletal muscle pump activity and sympathetic nervous system
activation) and inspiration-dependent cardiac filling on RSA magnitude.
Hypothesis:
Sympathetic activation during exercise will reduce RSA magnitude,
despite superimposed inspiratory-dependent and skeletal muscle
pump cardiac filling.
Experiment #2: Exercise and RSA

37. Methods and
Instrumentation
• Participants (n=13)
instrumented for
respiratory volumes and
heart rate
• Seated on a cycle
ergomenter
• Participant feedback on
respiratory volume via
computer screen
• RSA trials repeated at rest
and during exercise

38. Protocol
Lavoie et al., Manuscript in Preparation

39. Results – Raw Traces
Rest Exercise
Lavoie et al., Manuscript in Preparation

40. ResultsResults – RSA reactivity is reduced during exercise
Rest Exercise
Lavoie et al., Manuscript in Preparation

41. Results
P = 0.001
• RSA reactivity is
eliminated during
exercise
• This is despite an
increase in venous
return during exercise
• RSA is likely NOT driven
by increases in venous
return.
Lavoie et al., Manuscript in Preparation

42. • RSA is maintained during exercise.
• However, RSA reactivity is eliminated during exercise,
despite increases in venous return, likely because of
increased sympathetic activity.
• Questions: Will RSA be affected by acclimatization to
high altitude hypoxia? Could RSA reactivity
magnitude affect V/Q matching and oxygenation
during hypoxic stress?
Summary

43. Integrate and analyze all your
data streams in one place
Setting the pace for
Exercise Research
• Wireless physiological
monitoring and EMG
• Metabolic Systems
• Accelerometry
• Goniometers
• Human NIBP
• Stimulators

44. Himalayan Mountain Range - Tibet/Nepal
Mount Everest 8848 m (29,028 ft)
Atmospheric Pressure = 253 mm Hg
Available Oxygen ~33% of Sea Level

45. 0
100
200
300
400
500
600
700
800
0 1 2 3 4 5 6 7 8 9 10
GasPressure(mmHg)
Altitude (kilometres)
Patm
(mmHg)
PO2
(mmHg)
The Relationship Between Altitude
and Relative Gas Pressures
Day TA (2010). Human Adaptation to High Altitude Hypoxia: Getting High.
Biology on the Cutting Edge: Canadian Research and Issues around the Globe. (pp. 117-122) Pearson Education Canada, Toronto, Ontario.
Vancouver
Calgary Airplane Cabin
Everest
Half the available oxygen
of sea level

46. Aim:
To explore the relationship between superimposed high altitude hypoxia
and inspiration-dependent cardiac filling on RSA.
Hypothesis #1:
Increases in sympathetic nervous system during high altitude hypoxia will
reduce RSA magnitude (similar to exercise).
Hypothesis #2:
Larger RSA magnitude will improve oxygenation through improved V/Q
matching at altitude.
Experiment #3: High Altitude Hypoxia and RSA

47. Everest Base Camp (EBC) Trek

48. Why Nepal?

50. Altitude Comparisons:
Banff and Mt. Rundle = Kathmandu and Lukla

51. May 2016
23 participants recruited including nine paid trainees from MRU,
collaborators, industry partners (ADI) and community members from
across Canada, USA, New Zealand and Ireland.
Ethical Clearance:
• Mount Royal University Human Research Ethics Board 2015-26b
• Nepal Health Research Council 96/2016
Objective:
• A fast and light approach to high altitude acclimatization on a trek
to Everest Base Camp

52. Pelican cases packed outside the Lab April 29, 2016

53. Calgary Airport April 30, 2016

54. Kathmandu
(1400m)
Monjo
(2835m)
Namche
(3440m)
Tengboche
(3860m)
Pheriche
(4370m)
Lobuche
(4940m)
Gorak Shep
(5160m)
Pheriche
(4370m)
Pangboche
(3985m) Kunde
(3840m)
Namche
(3440m)
Phakding
(2610m)
Lukla
(2860m)
Kathmandu
(1400m)
0
500
1,000
1,500
2,000
2,500
3,000
3,500
4,000
4,500
5,000
5,500
6,000
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Day
Acetazolamide (Diamox)
125mg PO BID
Altitude(m)
Ascent-DescentProfile–Nepal2016

55. Lukla Airport (2800m)

59. Daily Measures: Nepal May 2016
• Between 6-8 am, before breakfast, following
one night at that altitude.
• Heart rate and peripheral oxygen saturation
• Respiratory rate and pressure of end-tidal CO2
• Blood pressure
• Acute Mountain Sickness scores (Lake Louise
Scoring system)
• Actigraph accelerometers for daily activity and
sleep disturbances
• Collected on ascent and descent
• n=21

60. Rest Day Measures:
Nepal May 2016
• On rest days during ascent between
10 AM and 5 PM
• Calgary (1045m), Namche (3440m),
Tengboche (3860m) and Pheriche
(4370m)
• [Hemoglobin] and hematocrit, urine
pH and renal reactivity, voluntary
breath holding, ventilatory
acclimatization, heart rate variability
(RSA reactivity)
• n=12

61. Namche (3440m)

63. Namche (3440m)

64. Tengboche (3860m)

66. Pheriche (4370m)

67. Pheriche (4370m)

69. Poincare Plot – Quantification of heart rate variability
Saran et al., Manuscript in Preparation

70. PoincarePlotsandAltitude
Saran et al., Manuscript in Preparation

71. RSA during
spontaneous
breathing via
SD1/SD2 ratio
Resting RSA
magnitude is not
changed with
high altitude
ascent
Saran et al., Manuscript in Preparation

72. • RSA quantified
using the peak-
valley approach
• Participant targets
inspired volume
through computer
screen feedback
RSA and targeted VTI

73. RSA Reactivity
Slopes and
Altitude
• RSA protocol during
ascent
• We plotted RSA
magnitude against
%FVC
• Slopes quantify “RSA
Reactivity”
• Slopes appear
unchanged with
altitude
Saran et al., Manuscript in Preparation

74. Results - RSA reactivity magnitude is not altitude dependent
Saran et al., Manuscript in Preparation

75. Gorak Shep (5160m)

76. 70
75
80
85
90
95
100
Kathmandu (1400m) Monjo (2840m) Namche (3440m) Tengboche (3860m) Pheriche (4370m) Lobuche (4940m) Gorak Shep (5160m)
PeripheralOxygenSaturation(%)
Location and Altitude
Oxygen
Saturation
and Altitude
• SpO2 (%) measured
every morning
during ascent
• Note the reduction
in SpO2 (%) with
increases in
altitude

77. RSA and V/Q matching hypothesis

78. The effects of RSA magnitude on oxygen saturation

79. • Resting RSA magnitude is unchanged with
acclimatization to high altitude (Poincare plots)
• RSA reactivity to targeted increases in VTI is also
unchanged with acclimatization to high altitude
• RSA magnitude does not improve oxygen saturation
in the context of hypoxia, suggesting V/Q matching
hypothesis is incorrect.
Summary

82. Summit of Kala Patthar (~5600m)

84. Acute Mountain Sickness (AMS)

85. Lukla (2800m)

87. Lukla Airport (2800m)

88. Kathmandu (1400m)

89. Calgary

90. Research in Austere Environments…
a balance between FEASABILITY and NOVELTY

91. Research in Austere
Environments
• Building the right team
• Organization and safety
• Managing expectations:
the needs of the
individual/team with
needs of the researchers

92. • Cultural sensitivity
• Personal and
interpersonal
perspectives
• Staying positive and
optimistic
• Keeping your sense of
humour
Research in Austere
Environments

93. • Creativity
• Improvisation
• Serendipity
• Persistence
• Compromise
• Problem solving
• Responsive to new opportunities
• Expect the unexpected
• Know the limitations of your gear
• Power?
Research in Austere
Environments

94. Undergradute Students!

97. Lake Louise AMS Scoring System [Roach et al., 1993]
[2] Moderate Headache
[3] Severe Headache. Incapacitating
Score =
2. Gastrointestinal Symptoms [0] Good Appetite
[1] Poor Appetite/Nausea
[2] Moderate Nausea/Vomiting
[3] Severe. Incapacitating Nausea and Vomiting
Score =
3. Fatigue and/or weakness [0] Not Tired or Weak
[1] Mild Fatigue/Weakness
[2] Moderate Fatigue/Weakness
[3] Severe Fatigue/Weakness
Score =
4. Dizziness/light-headedness [0] None
[1] Mild
[2] Moderate
[3] Severe. Incapacitating
Score =
5. Difficulty sleeping [0] Slept as well as usual
[1] Did not sleep as well as usual
[2] Woke many times. Poor night’s sleep
[3] Could not sleep at all
Score =
Sum 1-5 Total AMS Score =
Sum 1-4 Total AMS Score =
LAKE LOUISE AMS SCORING SYSTEM
Name:
Date:
Location and Altitude:
Instructions: Please circle the number of each item to correspond to HOW YOU FEEL AT THIS PRESENT MOMENT.
PLEASE ANSWER EVERY ITEM. If you do not have the specific symptom, please circle [0].
Self-Assessment Score
1. Headache [0] None at all
[1] Mild Headache
[2] Moderate Headache
[3] Severe Headache. Incapacitating
Score =
2. Gastrointestinal Symptoms [0] Good Appetite
[1] Poor Appetite/Nausea
[2] Moderate Nausea/Vomiting
[3] Severe. Incapacitating Nausea and Vomiting
Score =
3. Fatigue and/or weakness [0] Not Tired or Weak
[1] Mild Fatigue/Weakness

98. Thank You!
Dr. Trevor Day
Associate Professor of Physiology
Department of Biology
Faculty of Science and Technology
Mount Royal University
tday@mtroyal.ca
For additional information on the
solutions presented in this webinar
please visit www.adinstruments.com