Key result
Local forearm muscle heating during ischemic isometric handgrip elicited a significantly greater increase in renal vasoconstriction in older subjects compared to young subjects (18% vs 8%).
Why the study?
Does local muscle heating during ischemic isometric handgrip differentially affect renal vasoconstriction and MSNA in older compared to young subjects?
Does local muscle heating during ischemic isometric handgrip differentially affect renal vasoconstriction and MSNA in older compared to young subjects?
Absolute Event Rate: 18% vs 8%
p-value: p=0.01
Aging augments renal vasoconstriction and muscle sympathetic nerve activity in response to ischemic isometric handgrip during local muscle heating.
May indicate greater renal risk during ischemic exercise with local heating in older adults; leaves open clinical implications and need for validation.
The purpose of the study was to determine the interactive effect of aging and forearm muscle heating on renal vascular conductance and muscle sympathetic nerve activity (MSNA) during ischemic isometric handgrip. A tube-lined, water-perfused sleeve was used to heat the forearm in 12 young (27 +/- 1 yr) and 9 older (63 +/- 1 yr) subjects. Ischemic isometric handgrip was performed before and after heating. Muscle temperature (intramuscular thermistor) was 34.3 +/- 0.2 and 38.7 +/- 0.1 degrees C during normothermia and heating, respectively. At rest, heating had no effect on renal blood velocity (Doppler ultrasound) or renal vascular conductance in either group (young, n = 12; older, n = 8). Heating compared with normothermia caused a significantly greater increase in renal vasoconstriction during exercise and postexercise muscle ischemia (PEMI) in both groups. However, the increase in renal vasoconstriction during heating was greater in the older compared with the young subjects (18 +/- 3 vs. 8 +/- 3%). During handgrip, heating elicited greater increases in MSNA responses in the older group (young, n = 12; older, n = 6), whereas no statistical difference was observed between groups during PEMI. In summary, aging augments renal vascular responses to ischemic isometric handgrip during heating of the exercising muscle. The greater renal vasoconstriction was associated with augmented MSNA in the older subjects.
No takes yet. Share an insight, caveat, or question.
Kuipers et al. (2009) studied Healthy volunteers (n=21). Local forearm muscle heating vs. Normothermia was evaluated on Increase in renal vasoconstriction during exercise with heating compared to normothermia (p=0.01). Local forearm muscle heating during ischemic isometric handgrip elicited a significantly greater increase in renal vasoconstriction in older subjects compared to young subjects (18% vs 8%).
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: