Circadian Variations in Sympathetic Vasoconstriction in Older Adults with and Without Type 2 Diabetes

Circadian and sex differences in post‐ischemic vasodilation and reactive hyperemia in young individuals and elderly with and without type 2 diabetes

“…Lower VC values at baseline and after cuff release in the morning compared to the evening might also be consistent with increased sympathetic outflow levels at baseline in the morning, 3 but not with increased sympathetic vasoconstriction responsiveness in the morning. Indeed, we have previously shown that the peripheral vasoconstriction response triggered by acute activation of the sympathetic nervous system is similar between morning and evening in elderly individuals with and without T2DM of similar age to those recruited in the present study 35 . Our data also reveal a circadian variation of MAP in individuals with T2DM, but not in healthy age‐matched individuals.…”

“…Our data may suggest that this phenomenon takes place with aging and remains similar in the presence of T2DM despite the different vascular responses that individuals with T2DM may develop. Indeed, we have previously shown that individuals with T2DM seem to exhibit greater neurogenic vasodilation compared to similar age‐matched individuals without T2DM in response to sympathetic stress, 35 but this change does not appear to impact tissue vasodilation following a brief period of ischemia according to the present data. The greater morning vasoconstriction state at baseline could be determined by reduced endothelial function, greater sympathetic outflow, or both, and be a potential actor involved in the greater cardiovascular risk in the morning.…”

“…Indeed, we have previously shown that the peripheral vasoconstriction response triggered by acute activation of the sympathetic nervous system is similar between morning and evening in elderly individuals with and without T2DM of similar age to those recruited in the present study. 35 Our data also reveal a circadian variation of MAP in individuals with T2DM, but not in healthy agematched individuals. Increases in sympathetic outflow as a consequence of T2DM have been suggested.…”

“…Future studies are needed to score to what extent this reduction in vasodilation capacity may affect cardiovascular risk and determine whether this reduction in hyperemia critically affects tissue re‐oxygenation. The literature also reports important sex differences in BF regulation, as well as on the impact of cardiovascular disease, which vary with aging and the presence of T2DM 6,35,39,40 . Women show a lower cardiovascular risk than men until menopause 13 .…”

“…The literature also reports important sex differences in BF regulation, as well as on the impact of cardiovascular disease, which vary with aging and the presence of T2DM. 6,35,39,40 Women show a lower cardiovascular risk than men until menopause. 13 Thereafter, this trend starts reversing due to the decline in estrogen bioavailability and its cardioprotective effect.…”