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At least 235 records · Page 13Linked to original sources
PubMed1983

The effect of age on the renin-angiotensin-aldosterone systems and other physiological variables in normal subjects.

The influence of age on the renin-angiotensin-aldosterone (RAA) system in 125 normal subjects, ages ranging from 13-90, in Valencia, Venezuela, was evaluated. The subjects selected were tested during their normal life style, on their usual sodium and potassium diet. Their RAA system was stimulated by walking for 2-3 hours. A highly significant inverse correlation was found between age and stimulated plasma renin activity (r = -0.7149, p less than 0.001), and between age and urinary aldosterone (r = 0.4837, p less than 0.001). No significant correlation between age and serum aldosterone was found. The most significant changes in levels of these hormones were found between ages 55 and 60 when renin and aldosterone values decreased markedly. This decrease accelerates with increasing age. Plasma renin presented an appreciable percentage of decrease when compared to the highest levels found in the lowest age group; plasma renin decreased 80%, while urinary aldosterone decreased only 40% between ages 80 and 90. In the over-60 groups this relationship between plasma renin activity and urinary and serum aldosterone levels showed both aldosterone values were higher than the corresponding plasma renin levels. We have no clear explanation for the "physiologicalhyperaldosteronism" found in groups over age 60. Age is an indispensible consideration in normal RAA system values. More intensive studies of over age 60 subjects are necessary.

Adolescent↗
PubMed1980

Effects of a postexercise sauna bath on ECG pattern and other physiologic variables.

In an attempt to determine the risk of sauna bathing after heavy exercise, the responses of 10 clinically normal adult males (mean age 44 years) were observed and recorded for 26 min. during recovery from a standard, heavy exercise task on two separate days. On one of the 2d, recovery was interrupted by a 10-min (min 6-16) exposure to intense, dry heat (70-74 degrees C, 3-6% R.H.). The higher heart rate and rectal temperature during the treatment (min 6-16) and post treatment (min 16-26) phases on the experimental day were indicative of the expected response to the heat stress. Systolic blood pressure did not differ on experimental and control days during either phase of recovery, while diastolic blood pressure decreased during the heat exposure. Double product was higher during treatment and post-treatment phases on the experimental day indicating an increased myocardial O2 need in response to the heat. ECG (CM5) changes were limited to increased J-point displacement during the treatment phase on the experimental day, with S-T segment flattening (0.08 s) in one case, and prolongation of the Q-T interval (corrected for rate) with reduction in T-wave amplitude. The prolongation of electrical systole and T-wave flattening were not observed during exercise at comparable and higher heart rates and may be associated with reduced subendocardial perfusion. We concluded that sauna bathing of short duration after exercise represents a tenable risk for clinically normal males.

Adult↗