ABSTRACT
The purpose of this investigation was to examine the metabolic and cardiovascular demands of shallow-water exercise in older women. Sixteen active older women who were not taking cardiac medication participated in this investigation (mean +/- SE; age, 66.4 +/- 1.2 years). Testing included (a) resting metabolic rate and heart rate; (b) performing 5 8-minute, evenly paced, self-selected, submaximal, shallow-water exercise bouts. Expired air was collected during the final 3 minutes of each bout while the heart rate was recorded with a Polar heart rate monitor; and (c) a 40-minute water exercise class in which heart rate was monitored. One metabolic equivalent (MET) equaled 2.7 +/- 0.1 mlO2 x min(-1) x kg(-1), whereas resting heart rate was 63.4 +/- 2.2 b min(-1). Average submaximal MET and heart rate responses for exercise bouts 1-5 ranged from 2.8 +/- 0.1 to 5.8 +/- 0.3 and 89.7 +/- 3.0 to 119.5 +/- 3.3 b x min(-1), respectively. The rate of perceived exertion (RPE; Borg scale) response for bouts 1-5 ranged from 8.0 +/- 0.3 to 12.5 +/- 0.4. A linear relationship between MET vs. heart rate was found for each participant, with all r values greater than 0.97 (p < 0.05). The estimated MET and measured HR responses for the 40-minute water exercise class were as follows: warm-up, 4.0 +/- 0.3 and 99.5 +/- 3.4; body of workout, 5.2 +/- 0.4 and 110.0 +/- 3.8 (part 1), and 5.4 +/- 0.4 and 112.3 +/- 3.6 (part 2); cooldown, 3.6 +/- 0.3 and 95.5 +/- 3.0. The exercise intensity ranged from approximately 40-61% of the predicted maximum MET, and approximately 66-78% of the predicted heart rate maximum. Shallow-water exercise elicits metabolic and cardiovascular responses in older women that meet the American College of Sports Medicine exercise prescription guidelines for realizing health benefits.
Subject(s)
Aged/physiology , Basal Metabolism/physiology , Cardiovascular Physiological Phenomena , Exercise/physiology , Aged, 80 and over/physiology , Blood Pressure , Female , Heart Rate , Humans , Middle Aged , Oxygen Consumption , Physical Education and Training/methods , Physical Exertion , Regression AnalysisABSTRACT
The purpose of this study was to determine the relationship between oxygen demand, stroke rate and swimming velocity in competitive swimmers. The subjects who volunteered for this study were ten trained male swimmers (age, 16.7 +/- 0.4 yrs). VO2peak, swimming velocities at 80% (V80% VO2peak) and 100% (V100% VO2peak) of VO2peak and swimming velocity at the onset of blood lactate accumulation (VOBLA) were determined during a swimming economy profile test in a swimming flume. In the swimming economy test, determined by studying the relationship between oxygen uptake and swimming velocity cubed, the subjects were instructed to swim for six minutes at five or six submaximal swimming velocities. Steady-state oxygen uptake and stroke rate were calculated during the final two minutes of swimming. Results indicated that there were significant correlations between oxygen uptake and swimming velocity cubed (r = 0.963 to 0.998, p < 0.01), between oxygen uptake and stroke rate (r = 0.925 to 0.998, p < 0.01) and between stroke rate and swimming velocity cubed (r = 0.897, p < 0.05; to 0.994, p < 0.01) for all subjects. Furthermore, it was found that the slopes of the regression lines between oxygen uptake and swimming velocity cubed and between oxygen demand and stroke rate were significantly correlated to swimming performance indices (V80% VO2peak, V100% VO2peak and VOBLA). The results of this study suggest that the slope of the regression line between oxygen uptake and stroke rate can be utilized as an effective index of evaluating swimming performance.
Subject(s)
Oxygen Consumption , Physical Exertion/physiology , Swimming/physiology , Adolescent , Exercise/physiology , Humans , Lactates/blood , Lactic Acid , Male , Oxygen Consumption/physiology , Physical Endurance/physiologyABSTRACT
Despite similar rates of energy expenditure during training, it has been suggested that swimmers store greater amounts of body fat than runners. To investigate these discrepancies, eight male swimmers (S) and runners (R) were monitored during 45 min of swimming or running (75% VO2max), respectively, and six triathletes were monitored during swimming (ST) and running (RT). Each group was also monitored during two hours of recovery. Venous blood samples were obtained before exercise, immediately after exercise (0 min) and at 15, 30, 60 and 120 min of recovery. These samples were analyzed for glucose, lactate, glycerol, free fatty acids (FFA), insulin, glucagon, norepinephrine (NE) and epinephrine (E). Expired gases and heart rates (HR) were obtained during exercise and also during recovery. The caloric cost of recovery was similar, but the RER results suggested increased fat oxidation during recovery for the S and the ST. Serum glucose was greater (P less than 0.05) immediately after exercise for R (6.71 +/- 0.29 mmol/l) and RT (6.40 +/- 0.26) compared to the S (4.97 +/- 0.19) and ST (4.87 +/- 0.18), and was significantly elevated for the initial 30 min of recovery. FFA were similar throughout the recovery period; however, blood glycerol was greater immediately after exercise (0 min) for R compared to S (NS) and was significantly elevated after exercise (0 min) for RT compared to ST. Differences in blood glucose or fat release were not explained by differences in NE or E; however, the glucacon-to-insulin ratio was significantly greater after exercise in the S and ST compared to the R and RT.(ABSTRACT TRUNCATED AT 250 WORDS)
