ABSTRACT
This study investigated the combined effects of consuming a meal during postexercise hypotension (PEH) on hemodynamics. Nine healthy young male subjects performed each of three trials in random order: 1) cycling at 50% of heart rate reserve for 60 min, 2) oral ingestion of a carbohydrate liquid meal (75 g glucose), or 3) carbohydrate ingestion at 40 min after cycling exercise. Blood pressure, heart rate, cardiac output, and blood flow in the superior mesenteric (SMA), brachial, and popliteal arteries were measured continuously before and after each trial. Regional vascular conductance (VC) was calculated as blood flow/mean arterial pressure. Blood pressure decreased relative to baseline values (P < 0.05) after exercise cessation. Blood flow and VC in the calf and arm increased after exercise, whereas blood flow and VC in the SMA did not. Blood pressure did not change after meal ingestion; however, blood flow and VC significantly decreased in the brachial and popliteal arteries and increased in the SMA for 120 min after the meal (P < 0.05). When the meal was ingested during PEH, blood pressure decreased below PEH levels and remained decreased for 40 min before returning to postexercise levels. The sustained increase in blood flow and VC in the limbs after exercise was reduced to baseline resting levels immediately after the meal, postprandial cardiac output was unchanged by the increased blood flow in the SMA, and total VC and SMA VC increased. Healthy young subjects can suppress severe hypotension by vasoconstriction of the limbs even when carbohydrate is ingested during PEH.
Subject(s)
Blood Pressure/physiology , Eating/physiology , Exercise/physiology , Hemodynamics/physiology , Meals/physiology , Adult , Blood Pressure Determination/methods , Brachial Artery/metabolism , Brachial Artery/physiology , Cardiac Output/physiology , Dietary Carbohydrates/metabolism , Heart Rate/physiology , Humans , Hypotension/metabolism , Hypotension/physiopathology , Male , Mesenteric Arteries/metabolism , Mesenteric Arteries/physiology , Popliteal Artery/metabolism , Popliteal Artery/physiology , Postprandial Period/physiology , Regional Blood Flow/physiology , Rest/physiology , Vasoconstriction/physiology , Young AdultABSTRACT
We determined effect of aerobic exercise in early evening on the quality, quantity, and haemodynamic response of subsequent nocturnal sleep in the home. Ten healthy young participants performed two protocols, with/without cycle ergometer exercise (60 min at 50% heart rate reserve) in early evening. Blood pressure (BP) (Holter) and physical activity (accelerometer) were measured from late afternoon of day 1 until noon of next day (day 2). Additionally, at bedtime participants were equipped with a small device worn on the wrist that identified sleep stage. There were no substantial differences in objective indices of sleep between two protocols (total sleep time: 438 ± 76 vs. 457 ± 64 min; P > 0.10). BP during nocturnal sleep tended to be lowered by prior exercise (MAP: 71 ± 5 vs. 68 ± 6 mmHg; P = 0.08). Aerobic exercise in early evening apparently has no acute effect on sleep per se, but seems to have a residual effect on haemodynamics, i.e. prolongation of post-exercise hypotension.
Subject(s)
Exercise/physiology , Hemodynamics , Sleep , Actigraphy , Adolescent , Adult , Blood Pressure , Exercise Test , Heart Rate , Humans , Hypertension , Male , Plethysmography/instrumentation , Young AdultABSTRACT
BACKGROUND: Recently, it was reported in healthy young subjects that fructose containing drinks increased blood pressure acutely, without any apparent change in total vascular conductance (TVC). However, because it is well known that the splanchnic vasculature is dilated by oral fructose ingestion, it is assumed to be the concomitant vasoconstriction in other peripheral region(s) that is responsible for this finding. Thus, the purpose of this study was to determine the acute response of regional VC to oral fructose ingestion in young healthy humans. RESULTS: In 12 healthy young subjects, mean arterial blood pressure (MAP), heart rate, cardiac output, and blood flow (BF) in the superior mesenteric (SMA), brachial (BA), and popliteal (PA) arteries, in addition to forearm skin BF, were measured continuously for 2 h after ingestion of 400 ml fructose solution (containing 50 g fructose). Regional VC was calculated as BF/MAP. MAP increased for 120 min after fructose ingestion without any change in TVC. While VC in the SMA was elevated after ingestion, VC in BA and PA and forearm skin decreased. CONCLUSIONS: While TVC was apparently unchanged during the 2 h after fructose ingestion, there were coincident changes in regional VCs in the peripheral circulation, but no net change in TVC.
