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. 2015:2015:728145.
doi: 10.1155/2015/728145. Epub 2015 Mar 19.

The effects of cold and lower body negative pressure on cardiovascular homeostasis

David J Kean  1 , Corey A Peacock  2 , Gabriel J Sanders  3 , John McDaniel  4 , Lisa A C Colvin  5 , Ellen L Glickman  4
Affiliations

The effects of cold and lower body negative pressure on cardiovascular homeostasis

David J Kean et al. Biomed Res Int. 2015.

Abstract

Purpose: The purpose of this study is to determine how cold exposure and lower body negative pressure effected cardiovascular variables.

Methods: Eleven males (20.3 years ± 2.7) underwent two 20-minute exposures to LBNP. During the 2 trials, the subjects were exposed to cold air (10°C) (COLD) and to ambient temperature (23°C) (AMB). The trials consisted of a 100-minute pre-LBNP period followed by a 20-minute exposure to LBNP and then a 15-minute recovery period. Cardiovascular variables were recorded every 30 minutes using bioimpedance.

Results: When LBNP was applied during the AMB trials, stroke volume immediately decreased. During the COLD trial, there was a five-minute delay before the decrease in stroke volume. Heart rate increased immediately after LBNP initiation during the AMB trials but there was a delay in the increase during the COLD trials. That same pattern was followed with mean arterial blood pressures. Cerebral oxygenation was significantly lower throughout the COLD trial as compared to the AMB trials. Six subjects reported symptoms of syncope or presyncope during the AMB trials but there were no reports of symptoms during the COLD trials.

Conclusion: From analysis of this data, cold improved the subject's tolerance to LBNP.

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Figures

Figure 1
Figure 1
Changes in rectal temperature (°C) (M ± 95% CI) during pre-LBNP, LBNP, and post-LBNP periods.
Figure 2
Figure 2
Changes in mean skin temperature (°C) (M ± 95% CI) during pre-LBNP, LBNP, and post-LBNP periods.
Figure 3
Figure 3
Changes in mean arterial blood pressure (mmHg) (M ± 95% CI) during the pre-LBNP, LBNP, and post-LBNP periods.
Figure 4
Figure 4
Changes in heart rate (beats/min) (M ± 95% CI) during the pre-LBNP, LBNP, and post-LBNP periods.
Figure 5
Figure 5
Changes in stroke volume (mL × beat−1) (M ± 95% CI) during the pre-LBNP, LBNP, and post-LBNP periods.
Figure 6
Figure 6
Changes in cerebral oxygenation (%) (M ± 95% CI) during the pre-LBNP, LBNP, and post-LBNP periods.
Figure 7
Figure 7
The exterior of the environmental chamber at the Kent State Environmental Laboratory.
Figure 8
Figure 8
The LBNP box.
See this image and copyright information in PMC

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