The journals of gerontology. Series A, Biological sciences and medical sciences
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J. Gerontol. A Biol. Sci. Med. Sci. · Feb 2005
Randomized Controlled Trial Clinical TrialTai Chi and fall reductions in older adults: a randomized controlled trial.
The authors' objective was to evaluate the efficacy of a 6-month Tai Chi intervention for decreasing the number of falls and the risk for falling in older persons. ⋯ A three-times-per-week, 6-month Tai Chi program is effective in decreasing the number of falls, the risk for falling, and the fear of falling, and it improves functional balance and physical performance in physically inactive persons aged 70 years or older.
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J. Gerontol. A Biol. Sci. Med. Sci. · Feb 2005
Comparative StudyAge-related changes in microvascular blood flow and transcutaneous oxygen tension under Basal and stimulated conditions.
Adequate cutaneous microvascular blood flow and tissue oxygen tension are important prerequisites for successful tissue repair. The efficacy of tissue repair decreases with age and is linked to the age-related functional decline of unmyelinated sensory neurons that are important for inflammation and tissue repair. However, available information on the effect of these neuronal changes on microvascular blood flow and tissue oxygen tension is limited, particularly under control and injury conditions. The authors had two aims in this study: (a) to assess age-related changes in the relationship between microvascular blood flow and tissue oxygen perfusion under basal and two different stimulated conditions (sensory dependent and sensory independent), and (b) to clarify the biological meaning of transcutaneous partial pressure of oxygen (tcPO2) measurements. ⋯ The age-associated changes in basal and stimulated microvascular blood flow and tcPO2 could be attributed in part to altered neuronal function. Measuring tcPO2 at 39 degrees C showed a trend toward an increase with age. In contrast, a decrease with age was observed when tcPO2 was measured at 44 degrees C, a temperature sufficient to activate sensory nerve endings. The results may reflect a decline in sensory nerve function with age rather than a decrease in oxygen delivery for vascular reasons. This is supported by the complementary data showing a significant age-related decrease in stimulated blood flow in response to capsaicin, with no change in the response to the sensory-independent vasodilator acetylcholine. Thus, for clinical purposes, data obtained using the tcPO2 monitor should be interpreted with full knowledge of the conditions under which the measurements were made. Furthermore, for scientific purposes, the tcPO2 monitor could be used to assess sensory nerve function when sensors are heated to 44 degrees C.