PHYSIOLOGIC & METABOLIC VARIATION

Physiologic & Metabolic Variation in Hypoxia & Normoxia in Humans

Table of Contents

Chapter1: Introduction1

Background of the Study1

Purpose of study3

Significance of the study3

Rationale of the study5

Chapter 2: Literature Review7

Chapter 3: Methodology9

Lab Visit 1 - (Time required 3hrs)9

Pilot11

Lab Visit 2 - (Time required 5hrs)11

Lab Visit 3 - (Time required 30min per day)11

Lab Visit 4 (time required 3hrs)12

Subject requirements12

Subject Privacy12

Health Related Risks and Discomforts13

Chapter 4: Results & Discussion14

Chapter 5: Conclusion16

References20

Chapter 1: Introduction

Background of the Study

On exposure to hypoxia (as is experienced when at altitude) the human body makes certain physiological adaptations to compensate for the reduced partial pressure of oxygen (PO2) that exists. One of these adaptations is the increased release in the hormone Erythropoietin (EPO) and the subsequent increase in red blood cell (RBC) concentration. RBCs are responsible for carrying O2 from the environment, via the lungs, to the muscle. This RBC adaptation is thought to be a key indicator in an individual's ability to adjust to hypoxia and is associated with an improved exercise performance at altitude after a period of training and an improved work capacity on return to sea-level.

It has been shown that there is a large variation between individual's ability to physiologically cope with a given hypoxic demand (Baker et al., 1998; Chapman et al., 1998; Haymes et al., 1986; Basnyat et al., 2003; Levine et al., 1997; Niess et al., 2004; Stray-Gundersen et al., 1992; Stray-Gundersen et al., 2001). Particularly, the work by Chapman et al (1998) offered an important contribution to the altitude literature through identifying responders and non-responders to altitude exposure and training. This study and subsequent work demonstrated a relationship between a high and sustained increase in EPO response from altitude training amongst responders and their improved sea-level performance (Jedlickova et al., 2004). There have been several factors that are proposed to influence the magnitude of these individual differences in EPO response at a given altitude such as, individual differences in hypoxic ventilatory drive, oxygen (O2) half-saturation pressure of haemoglobin, and/or sensitivity to hypoxia at the point of EPO release (Chapman et al., 1998; Ge RL et al., 2002; Jedlickova et al., 2004).

Findings from investigations employing animal models suggest that such EPO differences are regulated by the physiological factors responsible for O2 availability in the kidney (i.e. hypoxic ventilatory response, pulmonary diffusing capacity, renal oxygen delivery and renal oxygen consumption (Jedlickova et al., 2004; Ou et al., 1998). Furthermore, Schoene et al. (1984) highlighted the relationship between hypoxic ventilatory response and benefits to exercise performance during hypoxic exposure. Individuals who respond with a strong hypoxic ventilatory drive benefit from an enhanced exercise efficiency at a given exercise intensity and should be able to ascend to a higher altitude with less difficulty (Schoene et al., 1984). It could, therefore, be hypothesised that an intervention that increases an individual's ventilatory drive may result in an enhanced physiological response to hypoxia.

A tool (POWERBreathe) used in the health domain has been applied to exercising the muscles responsible for inspiration and more recently, anecdotal evidence indicates performance ...