This study was conducted to determine whether submaximal cardiovascular responses at a given rate of work are different in children and adults, and, if different, what mechanisms are involved and whether the differences are exercise-modality dependent. A total of 24 children, 7 to 9 yr old, and 24 adults, 18 to 26 yr old (12 males and 12 females in each group), participated in both submaximal and maximal exercise tests on both the treadmill and cycle ergometer. With the use of regression analysis, it was determined that cardiac output (Q) was significantly lower (P

The cardiovascular system of children responds to exercise differently than does that of an adult, although the mechanisms behind the differences are unclear. During dynamic exercise, it has been reported that heart rate (HR) response to the initiation of exercise is both faster and slower in children than adults. Furthermore, HR recovery has been reported to be faster in children. During submaximal steady state exercise, HR and total peripheral resistance are higher, while stroke volume [SV (ml)] and cardiac output [Q (L/min)] are lower in children at a given rate of work. At maximal exercise intensities HR is higher while SV and Q are lower in children than adults. Differences in cardiovascular responses to dynamic exercise between young boys and girls have also been reported. The majority of studies report that HR is lower and SV is higher in boys than girls at a given rate of work, although data to the contrary have been reported. These differences seem to be related to larger hearts in the boys. Further, the majority of the studies report that Q is similar in young boys and girls at a given rate of work. Few studies have reported differences between boys and girls at maximal intensities of exercise, and the results of those studies are inconsistent. Less is known about cardiovascular responses of children to static exercise compared with adults. A number of studies have reported that HR response to handgrip exercise is greater in children than adults, while others have reported no difference in this response. Even fewer studies have compared boys and girls in their cardiovascular response to static exercise and the results of these studies are also inconsistent. During prolonged exercise both children and adults exhibit cardiovascular drift (gradual increase in HR and decrease in SV). The direction and degree to which these changes differ between children and adults is unclear, with both greater and lesser responses being reported in children. Few studies have investigated differences in cardiovascular response to prolonged exercise between boys and girls. Those that have, report no difference between young boys and girls.

The management of acute ischemic stroke has not made significant strides since the introduction of recombinant tissue plasminogen activator (r-TPA) two decades ago. The use of other therapies, such as heparin, aspirin, dipyridamole, and/or clopidogrel, have only moderately aided in the treatment of this ischemic disease. Therefore, major medical innovative approaches are critically needed. Because of the side effects associated with r-TPA (specifically bleeding) and its limited 3-h therapeutic window, new studies using current developments encountered in the molecular biology of ischemia are being incorporated into the potential therapy of ischemic stroke. A review of the major advances in the field, including glutamate receptor blockade, magnesium infusion, inflammation blockade, apoptosis inhibition, and other therapies, is introduced with special emphasis on the molecular findings recognized as targets for a better and more effective treatment. As new therapies are being considered, the time of administration is becoming a central point of study for the application of novel therapeutic initiatives.

A moderate dose of caffeine (5 mg.kg) does not affect metabolism (VO2 or RER) in young children at low-moderate intensities of exercise. However, CAF causes a significantly lower HR (bpm) and higher BP (mm Hg) in both young boys and girls.

This study determined the reproducibility of cardiovascular, respiratory, and metabolic responses to submaximal cycle ergometer exercise at two power outputs (50 W and 60% VO2max) on each of two separate days in a sample of 390 subjects (198 men and 192 women) participating in the HERITAGE Family Study. The same protocol was conducted across 3 d in an intracenter quality control substudy which included an additional 55 subjects. Reproducibility estimates included technical error, coefficient of variation, and intraclass correlation for each of the selected variables for both subject populations. Further, since the data were collected across four clinical centers, intraclass correlations were also computed separately by clinical center. Most variables were highly reproducible, with coefficients of variation below 9% and intraclass correlations over 0.80. These results were consistent for both subject populations and across all four clinical centers. Reproducibility indicators were generally better at the higher power output. It is concluded that within-subject day-to-day variation and measurement unreliabilities are generally small compared with the between-subject variance in the response to submaximal exercise at each of the clinical centers of the HERITAGE Family Study.