Active Ascent Exacerbates Hypoxia-Mediated Alterations of Creatine, Energy Recruitment, and Ketone Body Metabolism
Abstract
Hiking under hypoxic conditions exerts more demands on the body's metabolic systems due to the substantial increase in energy expenditure under a scarce oxygen supply. The current study involved the hiking exercise and 41 healthy Soldiers (mean SD; age=265yr) who were tested at their baseline residence (SL, 331 masl), transported to Taos, NM (2845 masl), then immediately hiked (n=21) or were driven (n=20) to a high-altitude (HA, 3600 masl) facility where they resided for the next 4 days. Results demonstrated that hypoxia effects on urinary metabolite clearance were mostly transient for individuals who were driven, with most differences from SL noted only on HA day 1. Chronic hypoxia effects for this group were observed for pyruvate, citrate, sarcosine, and hypoxanthine as clearance alterations of these metabolites persisted at day 3 and/or day 4 at HA. Interestingly, hiking exacerbated hypoxia-mediated metabolite alterations. Metabolic pathways that were most affected belong to the energy, nicotinamide, ketone body, fatty acid, phospholipid, and neurotransmitter metabolism pathways. Evidence for hiking-induced enhancement of metabolite clearance is reflected in the: (1) profound changes noted on the first and second day of altitude exposure; (2) consistently elevated clearances for citrate, acetate, and isobutyrate throughout of the entire stay at HA; and (3) the number of alterations noted on days 3 and 4 at HA, all found only in subjects who hiked to HA. Taken together, the current study's findings suggest that additional energy demands (i.e., uphill hiking) prior to sojourn at HA exacerbates altitude-induced alterations in urinary metabolite clearance, altering the acclimatization timeline.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 2024
- Accession Number
- AD1229480
Entities
People
- Beth A. Beidleman
- Camilla A. Mauzy
- Isaie Sibomana
- J. P. Karl
- Janet E. Staab
- Peter S. Figueiredo
- Steven D. Landspurg
Organizations
- 711th Human Performance Wing