RPE during prolonged cycling with and without carbohydrate ingestion in boys and men.
OBJECTIVE
To examine the effect of prolonged cycling on ratings of perceived exertion (RPE) in boys and men and whether carbohydrate (CHO) ingestion would lower RPE during exercise.


METHODS
Ten boys (9-10 yr) and 10 men (20-25 yr) cycled for 60 min at approximately 70% VO2peak on two occasions. In a double-blind, counterbalanced design, a total volume of 24 mL.kg(-1) body mass of either a 6% CHO-electrolyte (CT) or flavored water (WT) beverage was consumed intermittently before and during exercise in each trial. Oxygen consumption (VO2), ventilation (VE), respiratory rate (RR), RPE (Borg's 6-20 scale), and heart rate (HR) were recorded periodically throughout exercise. Plasma glucose (GLU) was determined before and after exercise.


RESULTS
Postexercise GLU was not different between age groups but higher (P<0.001) during CT (5.6 +/- 0.2 mmol.L(-1)) compared with WT (4.7 +/- 0.1 mmol.L(-1)). CHO ingestion had no effect (P>0.05) on VO2, VE, RR, or RPE in either group. RR during exercise was higher (P<0.01) in boys (39.0 +/- 2.2 breaths.min(-1)) than in men (30.9 +/- 1.3 breaths.min(-1)). HR was slightly higher (P=0.047) during CT (160 +/- 3 beats.min(-1)) compared with WT (156 +/- 4 beats.min(-1)) and increased less over time (P<0.01) in boys compared with men. RPE at 5 min of exercise was similar (P>0.05) between boys (11.8 +/- 0.7) and men (12.0 +/- 0.7) but increased faster (P<0.01) over time in boys. The average exercise RPE was higher (P<0.01) in boys (15.8 +/- 0.5) than in men (14.0 +/- 0.4).


CONCLUSIONS
The higher and faster increase in RPE during exercise in boys, compared with men, may reflect a sensitivity to RR that outweighed any effect of CHO ingestion on RPE.
Timmons
Brian W
BW
Children's Exercise and Nutrition Centre, McMaster University, Hamilton, Ontario, Canada.
Bar-Or
Oded
O
D000328:Adult; D001642:Bicycling; D001786:Blood Glucose; D002241:Carbohydrates / Q000008:administration & dosage* / Q000097:blood; D002648:Child; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006339:Heart Rate; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D010465:Perception
D001786:Blood Glucose; D002241:Carbohydrates