Re-evaluation of birth weights at high altitude. Study of babies born to mothers living at an altitude of 3,100 meters.

Babies born at altitudes above 2,700 meters have been reported to be below normal birth weight and small for gestational age (SGA). In a study of a specific community (Leadville, Colorado, altitude 3,100 meters) over a period of 14 months (ending November, 1978), 215 newborn infants were found to be appropriate for gestational age (AGA), with the entire group having a mean birth weight (3.16 kilograms) similar to that of newborn infants in Denver, Colorado (3.12 kilograms). This study from a community with a stable population indicates that babies born at high altitude are AGA. The increased morbidity which does occur for these babies is not due to SGA factors.

Sleep metabolism and age.

Continuous recordings were made of oxygen consumption (VO2) and EEG, EMG, and EOG during two nights of sleep for 20 men who were between 19 and 63 yr. old. There was a linear decrease in overnight oxygen consumption with age, even though the older men slept less and woke more often than the younger ones. On the first night, VO2 was higher, and sleep stages less like normal than on the second. In the second night data, individual oxygen consumptions averaged over the whole night ranged from 138 to 482 ml/min (61-247 ml/m2timesmin). No relationship appeared between stage of sleep and VO2 level, but there was usually a decline in VO2 in the first hour of sleep, and a slow rise in the 2-3 h before awaking. Periodic breathing was observed in the men older than 45 yr.