Publication Date

2016-09-07

Availability

Open access

Embargo Period

2016-09-07

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PHD)

Department

Kinesiology and Sport Sciences (Education)

Date of Defense

2016-08-24

First Committee Member

Kevin Jacobs

Second Committee Member

Arlette Perry

Third Committee Member

Joseph Signorile

Fourth Committee Member

Brian Arwari

Fifth Committee Member

Soyeon Ahn

Abstract

The present study was conducted to examine the behavioral cognitive and neurophysiological effects of acute exposure to simulated moderate and high altitudes at rest and during exercise in an effort to delineate whether there is a level of simulated altitude beyond which cognition and neurophysiological function are impaired and whether exercise improves or worsens cognitive function during exposure to simulated altitude. Dependent variables included accuracy and reaction time on a number of behavioral cognitive tasks, and the amplitude and latency of their associated event-related potentials. Fourteen recreationally active college students (M=9, F=5) aged 18-35 participated in this study, which consisted of six experimental days, with three simulated altitude conditions: sea level (SL), simulated moderate altitude (MA; 15.4% FIO2, ~2400 m) or simulated high altitude (HA; 12.8% FIO2, ~3900 m); and two exercise conditions: rest or moderate intensity cycling exercise at 60% altitude-specific peak power output, in a randomized-order, crossover design. Simulated altitude slowed down reaction time on a number of tasks (p=0.04), while exercise improved reaction time (p=0.01), without decrements in accuracy under any condition. These effects were partially explained by alterations in associated event-related potential amplitudes and latencies, such as slower N200 latencies with altitude (p=0.04) but faster latencies with exercise (p<0.01), as well as reduced P300 amplitude and slower latency with altitude (p<0.01), and reduced amplitude but faster latency with exercise (p=0.03). Acute exposure to simulated altitudes slows behavioral cognitive reaction time while preserving task accuracy. An acute bout of moderate intensity cycling exercise improves reaction times so that they are comparable to those achieved without exercise or altitude, at least in instances where exercise does not exacerbate the peripheral oxygen saturation drops seen with simulated altitude.

Keywords

simulated altitude; cognition; electroencephalography; physical activity

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