Sleep and Breathing at High Altitude

Wickramasinghe, Himanshu; Anholm, James D.

doi:10.1007/s11325-999-0089-1

Cited by 75 publications

(44 citation statements)

References 58 publications

(125 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[17][18][19][20] In our research, we concentrated on the breathing abnormalities occurring in patients exposed to high altitude. The following variables CAL, VL, and CD were short in duration.…”

Section: Discussionmentioning

confidence: 99%

Ventilatory Cycle Measurements and Loop Gain in Central Apnea in Mining Drivers Exposed to Intermittent Altitude

Castro

Liendo²,

Ortiz

et al. 2017

Journal of Clinical Sleep Medicine

View full text Add to dashboard Cite

Study Objectives: By measuring the apnea length, ventilatory phase, respiratory cycle length, and loop gain, we can further characterize the central apneas of high altitude (CAHA). Methods: Sixty-three drivers of all-terrain vehicles, working in a Peruvian mine located at 2,020 meters above sea level (MASL), were evaluated. A respiratory polygraph was performed in the first night they slept at high altitude. None of the subjects were exposed to oxygen during the test or acetazolamide in the preceding days of the test. Results: Sixty-three respiratory polygraphs were performed, and 59 were considered for analysis. Forty-six (78%) were normal, 6 (10%) had OSA, and 7 (12%) had CAHA. Key data from subjects include: residing altitude: 341 ± 828 MASL, Lake Louise scoring: 0.4 ± 0.8, Epworth score: 3.4 ± 2.7, apneahypopnea index: 35.7 ± 19.3, CA index: 13.4 ± 14.2, CA length: 14.4 ± 3.6 sec, ventilatory length: 13.5 ± 2.9 sec, cycle length: 26.5 ± 4.0 sec, ventilatory length/CA length ratio 0.9 ± 0.3 and circulatory delay 13.3 ± 2.9 sec. Duty ratio media [ventilatory duration/cycle duration] was 0.522 ± 0 0.128 [0.308-0.700] and loop gain was calculated from the duty ratio utilizing this formula: LG = 2π / [(2πDR-sin(2πDR)]. All subjects have a high loop gain media 2.415 ± 1.761 [1. 175-6.260]. Multiple correlations were established with loop gain values, but the only significant correlation detected was between central apnea index and loop gain. Conclusions: Twelve percent of the studied population had CAHA. Measurements of respiratory cycle in workers with CAHA are more similar to idiopathic central apneas rather than Hunter-Cheyne-Stokes respiration. Also, there was a high degree of correlation between severity of central apnea and the degree of loop gain. The abnormal breathing patterns in those subjects could affect the sleep quality and potentially increase the risk for work accidents. Keywords: driver, sleep, central apnea, high altitude, loop gain Citation: Rey de Castro J, Liendo A, Ortiz O, Rosales-Mayor E, Liendo C. Ventilatory cycle measurements and loop gain in central apnea in mining drivers exposed to intermittent altitude.

show abstract

Section: Discussionmentioning

confidence: 99%

Ventilatory Cycle Measurements and Loop Gain in Central Apnea in Mining Drivers Exposed to Intermittent Altitude

Castro

Liendo²,

Ortiz

et al. 2017

Journal of Clinical Sleep Medicine

View full text Add to dashboard Cite

show abstract

“…91,99 It is important to note that this occurs despite the fact that hypocapnia increases over time. As such, it appears that the responsiveness of the ventilatory inhibition by hypocapnia is improved with acclimatization to altitude.…”

Section: Effects Of Acute Altitude Residence On Sleep Qualitymentioning

confidence: 99%

Short-term arrival strategies for endurance exercise performance at moderate altitude

Foss

Constantini

Mickleborough

et al. 2017

Journal of Applied Physiology

View full text Add to dashboard Cite

For sea level-based endurance athletes who compete at moderate and high altitudes, many are not logistically able to arrive at altitude weeks before the event to fully acclimatize. For those who can only arrive at altitude the night before competition, we asked if there is a physiological and performance advantage in reducing altitude exposure time to 2 h before competition. On three separate visits, 10 cyclists completed overnight laboratory exposures of: 1) a 14-h exposure to normobaric hypoxia (16.2% O2, simulating 2,500 m; 14H), 2) a 12-h exposure to normoxia, then a 2-h hypoxic exposure (2H), and 3) a 14-h exposure to normoxia (CON). Immediately following each exposure, subjects completed a 20-km cycle ergometry time trial in normoxia (CON) or 16.2% O2 (14H and 2H). Measures of plasma volume changes, sleep quality, ventilatory acclimatization, perceived exertion, oxygen uptake, and 20-km time were collected. No significant differences were observed in performance measures or perceived exertion between hypoxic trials. Plasma volume loss was significantly greater during 14H than 2H and CON. No differences in ventilatory acclimatization or sleep quality were observed between trials. Although some divergent 20-km performance responses were observed between 14H and 2H, they were not explained by the physiological measures completed. The data suggest that endurance athletes who are logistically restricted from arriving at altitude more than the evening before competition would not gain an advantage by delaying their arrival until a few hours before the competition, although unique individual responses may ultimately influence optimal arrival strategy. NEW & NOTEWORTHY For athletes who cannot arrive at altitude multiple days before an endurance competition to properly acclimatize, this study asked if shortening hypoxic exposure time to 2 h before a competition was more advantageous than arrival at altitude the evening before competition. Our data suggest that athletes who cannot arrive at altitude with adequate time for complete acclimatization can choose the short-term arrival strategy that best fits with the logistics of their travel.

show abstract

“…While this periodicity decreases with successive nights at altitude, it has been shown to persist at elevations above 4500m. 91 Early studies on sleep physiology at altitude showed the alteration of sleep cycles experienced by subjects. Joern et al (1970) found that at pressures similar to moderate altitudes, sleep stage distribution was altered so that Stages 3 and 4 were almost eliminated and REM sleep was reduced by 50%.…”

Section: Effects Of Acute Altitude Residence On Sleep Qualitymentioning

confidence: 99%

“…Subsequent studies have shown similar results. 91,[93][94][95] Although it appears that the increased arousals during sleep at altitude are connected to periodic breathing, the mechanisms that contribute to the shift in sleep patterns are poorly understood. 90 The mechanism of periodic breathing, though, was first demonstrated by Douglas and Haldane (1909).…”

Section: Effects Of Acute Altitude Residence On Sleep Qualitymentioning

confidence: 99%

Short-Term Arrival Strategies for Endurance Exercise Performance at Moderate Altitude

Foss

Constantini

Mickleborough

et al. 2015

Medicine &Amp; Science in Sports &Amp; Exercise

View full text Add to dashboard Cite

Sleep and Breathing at High Altitude

Cited by 75 publications

References 58 publications

Ventilatory Cycle Measurements and Loop Gain in Central Apnea in Mining Drivers Exposed to Intermittent Altitude

Ventilatory Cycle Measurements and Loop Gain in Central Apnea in Mining Drivers Exposed to Intermittent Altitude

Short-term arrival strategies for endurance exercise performance at moderate altitude

Short-Term Arrival Strategies for Endurance Exercise Performance at Moderate Altitude

Contact Info

Product

Resources

About