Jill Wilson

AIM: High-intensity exercise is time-limited by onset of fatigue, marked by accumulation of blood lactate. This is accentuated at maximal, all-out exercise that rapidly accumulates high blood lactate. The optimal active recovery intensity for clearing lactate after such maximal, all-out exercise remains unknown. Thus, we studied the intensity-dependence of lactate clearance during active recovery after maximal exercise. METHODS: We constructed a standardized maximal, all-out treadmill exercise protocol that predictably lead to voluntary exhaustion and blood lactate concentration>10 mM. Next, subjects ran series of all-out bouts that increased blood lactate concentration to 11.5±0.2 mM, followed by recovery exercises ranging 0% (passive)-100% of the lactate threshold. RESULTS: Repeated measurements showed faster lactate clearance during active versus passive recovery (P<0.01), and that active recovery at 60-100% of lactate threshold was more efficient for lactate clearance than lower intensity recovery (P<0.05). Active recovery at 80% of lactate threshold had the highest rate of and shortest time constant for lactate clearance (P<0.05), whereas the response during the other intensities was graded (100%=60%>40%>passive recovery, P<0.05). CONCLUSION: Active recovery after maximal all-out exercise clears accumulated blood lactate faster than passive recovery in an intensity-dependent manner, with maximum clearance occurring at active recovery of 80% of lactate threshold.

PURPOSE: This investigation was conducted to compare the physiological responses of men and women, both during and following an exercise bout at the same relative submaximal intensity. METHODS: Ten untrained men (20.7+/-0.5 yr, 178.4+/-2.3 cm, 79.6+/-4.8 kg; mean+/-SE) and 10 untrained women (20.3+/-0.3 yr, 163.8+/-2.2 cm, 59.5+/-2.1 kg) cycled for 30 min at 60-65% of their predetermined peak oxygen uptake. Physiological variables were measured before exercise, at 15 and 30 min of exercise, and at 5 and 15 min postexercise. For each variable of interest, a two-way repeated-measures of analysis was used to assess the main effects of gender and time, along with potential interactive effects. RESULTS: Our data revealed that for many variables including HR, relative HR (% peak value), mean arterial pressure, and rectal temperature, men and women responded similarly both during exercise and throughout the recovery period. In contrast, significant (P<or=0.05) gender-related differences were noted for RER, plasma lactate, systolic blood pressure, and plasma volume shifts. In each of those variables, values displayed by men during exercise were significantly greater than those observed among women. However, with the exception of plasma lactate, those gender-related differences did not persist into recovery. CONCLUSION: During exercise of the same relative submaximal intensity, some physiological parameters responded likewise in young men and young women, whereas others did not. Among those variables that demonstrated significant gender-related differences, all but one (plasma lactate) were obscured within 5 min of postexercise recovery.

PURPOSE The aim of this investigation was to determine whether gender influenced physiological responses to exercise and/or during passive recovery from that stimulus. METHODS Ten healthy, but untrained men (20.7 ± 0.5 yrs, 178.4 ± 2.3 cm, 79.6 ± 4.8 kg: mean ± SE) and 10 healthy, untrained women (20.3 ± 0.3 yrs, 163.8 ± 2.2 cm, 59.5 ± 2.1 kg) served as subjects. The two groups reported similar levels of habitual exercise and physical activity. After determining peak VO2 with a graded exercise test on an electrically braked cycle ergometer, subjects returned to the laboratory several days later to cycle for 30 min at 60–65% of their peak aerobic power. Heart rate, blood pressure, and rectal temperature were measured before exercise, at the 15th and 30th min of exercise, as well as 5 and 15 min post-exercise. Blood samples were collected at those same intervals and plasma volume shifts were calculated. Metabolic data were collected continuously throughout exercise and recovery. RESULTS Heart rate responses during exercise and recovery were similar (P>0.05) between men and women. Additionally, there were no significant gender differences in temperature responses during or after exercise. Although no gender effect on mean arterial pressure was identified, systolic pressure was higher in men at 15 and 30 min of exercise (P<0.05). This difference contributed to the significantly (P<0.05) greater plasma volume shifts experienced by men while cycling. Relative oxygen uptake (% peak VO2) was not different between men and women either during, or following cycling. In contrast, respiratory exchange ratio (RER) was found to be significantly greater among men than women during exercise. CONCLUSIONS These data indicate that, in general, men and women responded similarly to exercise of the same relative intensity, and displayed comparable post-exercise recovery rates. However, in selected physiological parameters gender differences were apparent, most notably in systolic blood pressure, plasma volume shifts, and RER.

PURPOSE The aim of this investigation was to determine whether gender influenced physiological responses to exercise and/or during passive recovery from that stimulus. METHODS Ten healthy, but untrained men (20.7 ± 0.5 yrs, 178.4 ± 2.3 cm, 79.6 ± 4.8 kg: mean ± SE) and 10 healthy, untrained women (20.3 ± 0.3 yrs, 163.8 ± 2.2 cm, 59.5 ± 2.1 kg) served as subjects. The two groups reported similar levels of habitual exercise and physical activity. After determining peak VO2 with a graded exercise test on an electrically braked cycle ergometer, subjects returned to the laboratory several days later to cycle for 30 min at 60–65% of their peak aerobic power. Heart rate, blood pressure, and rectal temperature were measured before exercise, at the 15th and 30th min of exercise, as well as 5 and 15 min post-exercise. Blood samples were collected at those same intervals and plasma volume shifts were calculated. Metabolic data were collected continuously throughout exercise and recovery. RESULTS Heart rate responses during exercise and recovery were similar (P>0.05) between men and women. Additionally, there were no significant gender differences in temperature responses during or after exercise. Although no gender effect on mean arterial pressure was identified, systolic pressure was higher in men at 15 and 30 min of exercise (P<0.05). This difference contributed to the significantly (P<0.05) greater plasma volume shifts experienced by men while cycling. Relative oxygen uptake (% peak VO2) was not different between men and women either during, or following cycling. In contrast, respiratory exchange ratio (RER) was found to be significantly greater among men than women during exercise. CONCLUSIONS These data indicate that, in general, men and women responded similarly to exercise of the same relative intensity, and displayed comparable post-exercise recovery rates. However, in selected physiological parameters gender differences were apparent, most notably in systolic blood pressure, plasma volume shifts, and RER.