title: Exercise-induced changes in oxygen saturation in the calf muscles of elderly subjects with peripheral vascular disease.
abstract: This study noninvasively measured hemoglobin oxygen saturation in young (n = 6, 28 +/- 6 yrs), old healthy (n = 20, 68 +/- 7 yrs), and old subjects with mild peripheral vascular disease (PVD) (n = 8, 72 +/- 4 yrs). Hemoglobin oxygen saturation was measured as the difference in absorption at 760 and 850 nm light using near-infrared spectroscopy (NIRS). The lateral soleus muscle was studied after mild plantar flexion exercise. The time constant of recovery of oxygen saturation (HBO2Tc) was 21.5 +/- 8.6 s in young, 26.9 +/- 13.5 s in old healthy subjects. PVD subjects had HbO2Tc values of 104.4 +/- 41.1 s in their "bad" leg and 57.6 +/- 42.2 s in their "good" leg. The correlation between HbO2Tc and ankle-arm pressures was significant (r2 = .63, p < .001). Six younger normal, five older normal, and seven PVD subjects also performed a progressive walking test. Normal subjects completed the test without difficulty, and older normal subjects showed progressive deoxygenation. PVD subjects complained of calf pain (4 out of 5 were able to finish) and showed near-maximal deoxygenation throughout the test. In summary, NIRS measurements show promise as a method of evaluating the kinetics of oxygen saturation, particularly in patients with mild peripheral vascular disease.
authors.affiliation: Department of Medicine, Medical College of Pennsylvania, Philadelphia.
authors.forename: K K
authors.initials: KK
authors.lastname: McCully
authors.forename: C
authors.initials: C
authors.lastname: Halber
authors.forename: J D
authors.initials: JD
authors.lastname: Posner
mesh_terms: D000328:Adult; D000368:Aged; D000842:Ankle / Q000502:physiology; D001132:Arm / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D007383:Intermittent Claudication / Q000378:metabolism / Q000503:physiopathology; D007866:Leg; D008875:Middle Aged; D009132:Muscles / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology*; D010146:Pain / Q000503:physiopathology; D016491:Peripheral Vascular Diseases / Q000378:metabolism* / Q000503:physiopathology; D005082:Physical Exertion / Q000502:physiology*; D013055:Spectrophotometry, Infrared; D016138:Walking / Q000502:physiology
chemical_list: D006454:Hemoglobins