A-17 Free Communication/Slide - Older Adults: MAY 28, 2008 9:30 AM - 11:30 AM ROOM: 104
PURPOSE: The objective of the present investigation was to compare the physiological responses of young and aged women during exercise of the same relative intensity, as well as during post-exercise recovery.
METHODS: Ten young (20.3 ± 0.3 yrs; mean ± SE) and 10 aged (75.5 ± 1.2 yrs) women with similar levels of habitual/recreational physical activity, served as subjects. Each subject initially performed a graded exercise test on a cycle ergometer to the point of volitional exhaustion in order to establish peak oxygen uptake (VO2). Subjects later returned to the laboratory to cycle at 60-65% of their peak VO2 for 30 min. Physiological variables including heart rate, blood pressure, rectal temperature, plasma lactate and glucose concentrations, and respiratory exchange ratio (RER) were quantified before exercise, at the 15th and 30th minute of exercise, as well as at 5 and 15 min post-exercise.
RESULTS: During exercise and throughout recovery, young women displayed significantly (P<0.05) higher heart rates than aged women. In contrast, mean arterial blood pressure was significantly higher among aged women both during exercise and throughout recovery. Rectal temperature was found to be higher among young than in aged women during exercise and at 5 min post-exercise. Our data also showed that compared to young women, plasma glucose levels were significantly higher among aged women both during and throughout recovery. Conversely, young women displayed higher plasma lactate concentrations than aged women during exercise as well as throughout the 15 min recovery period. Finally, the respiratory exchange ratio of young women was significantly higher than that observed among aged ones, indicating a greater reliance by young women upon carbohydrates as energy substrate during exercise.
CONCLUSIONS: Even when relative intensity is held constant, aging modulates the pattern of metabolic, cardiovascular, thermoregulatory, and plasma metabolite responses during exercise and post-exercise recovery in women.
Supported by The Borgenicht Program for Aging Studies and Exercise Science