Age-related responses of vasoactive factors during acute exercise

To evaluate the age-related response of vasoactive factors during acute exe rcise, young (n=8, aged 23.6+/-2 years) and old (n=13, aged 77+/-6 years) h ealthy Volunteers performed a stress test using a treadmill, and blood samp les were taken before and after exercise. There were neither basal told peo ple 77+/-53 vs. young people 67.6+/-40 pg/ml) nor peak exercise-related tol d people 77+/-43 vs. young people 66.8+/-34 pg/ml) differences in plasma ad renomedullin (AM) between both groups. AM did not increase with exercise in either group. Regarding plasma cAMP, there were neither basal nor exercise related differences, but this nucleotide increased with exercise in both g roups told people p<0.0001, young people p<0.05). Plasma Atrial Natriuretic Peptide (ANP) was higher in basal (116.3+/-64 vs. 46.8+/-21 pg/ml, p<0.003 ) and after exercise samples (150.2+/-76.5 vs. 68.7+/-29.5 pg/ml, p<0.004) in old people as compared with young people. Old people showed an increase in ANP with exercise (p<0.05), but in young people, though there was a tren d to increase, it did not reach statistical significance, There were neithe r basal nor exercise related differences in plasma cGMP, but this nucleotid e increased with exercise in both groups. Angiotensin II (AT-II) levels wer e lower in basal and after exercise samples in old people as compared with young people. AT-II levels did not increase with exercise in either group. These data suggest that, with increasing age, the vascular tree develops re sistance to ANP and higher sensitivity to AT-II, while AM levels do not cha nge. Exercise makes ANP changes more evident, while AM and AT-II are not mo dified.