Clinical trial NCT00001519: Oxygen Uptake Kinetics During Recovery From Maximal and Submaximal Exercise
Official title: Oxygen Uptake Kinetics During Recovery From Maximal and Submaximal Exercise
Study type: OBSERVATIONAL
Overall status: COMPLETED
Conditions: Healthy
Keywords: Exercise
Exercise Intensity
Non-Linear Regression
Oxygen Uptake
Recovery
Subject Comparison
Time Constant
VO2
Lead sponsor: National Institutes of Health Clinical Center (CC)
Sponsor class: NIH
First posted: 2002-12-10
Enrollment: 5
Sex: ALL
Standard ages: CHILD
ADULT
OLDER_ADULT
Accepts healthy volunteers: yes

Brief summary: Measurements of dynamic changes in oxygen uptake (VO2 kinetics) during recovery from exercise may describe regulatory control of oxygen transport and utilization and have greater reliability and less inherent risk than assessment of maximal oxygen uptake (VO2max) in patients for whom exercise is limited by pain, excessive fatigue, dyspnea and motivation. The purpose of this pilot study is to evaluate the effect of exercise intensity on the time constant describing changes in VO2 (tauVO2) during recovery from one minute of constant work rate exercise. Five normal healthy volunteers ages 18 and older will perform a progressive maximal aerobic exercise test, using a cycle ergometer, to determine VO2max and lactate threshold (LT) estimated by gas exchange. Each subject will also complete a series of maximal constant work rate tests and submaximal constant work rate tests at 80% LT and 50% of the difference between LT and VO2max (50% delta). Breath by breath variability and VO2 span will be used to determine the number of constant work rate test repetitions, for each subject for each exercise intensity, needed to establish confidence in tauVO2. A mean response profile of VO2 recovery kinetics for each exercise intensity will be analyzed using non-linear regression to determine tauVO2. To examine the effect of exercise intensity on tauVO2, one way analysis of variance will be used to determine whether differences exist among maximal and submaximal (80% LT and 50% delta) time constants. We hypothesize that there will be no significant differences among time constants for VO2 during recovery from maximal and submaximal constant work rate exercise lasting one minute. The results of this study are expected to provide increased understanding of the measurement of VO2 kinetics during recovery.

Detailed description: Measurements of dynamic changes in oxygen uptake (VO2 kinetics) during recovery from exercise may describe regulatory control of oxygen transport and utilization and have greater reliability and less inherent risk than assessment of maximal oxygen uptake (VO2max) in patients for whom exercise is limited by pain, excessive fatigue, dyspnea and motivation. The purpose of this pilot study is to evaluate the effect of exercise intensity on the time constant describing changes in VO2 (tauVO2) during recovery from one minute of constant work rate exercise. Five normal healthy volunteers ages 18 and older will perform a progressive maximal aerobic exercise test, using a cycle ergometer, to determine VO2max and lactate threshold (LT) estimated by gas exchange. Each subject will also complete a series of maximal constant work rate tests and submaximal constant work rate tests at 80% LT and 50% of the difference between LT and VO2max (50% delta). Breath by breath variability and VO2 span will be used to determine the number of constant work rate test repetitions, for each subject for each exercise intensity, needed to establish confidence in tauVO2. A mean response profile of VO2 recovery kinetics for each exercise intensity will be analyzed using non-linear regression to determine tauVO2. To examine the effect of exercise intensity on tauVO2, one way analysis of variance will be used to determine whether differences exist among maximal and submaximal (80% LT and 50% delta) time constants. We hypothesize that there will be no significant differences among time constants for VO2 during recovery from maximal and submaximal constant work rate exercise lasting one minute. The results of this study are expected to provide increased understanding of the measurement of VO2 kinetics during recovery.

Eligibility criteria: Normal healthy subjects ages 18 and older.

Primary outcomes:
Secondary outcomes:
Other outcomes:
Locations:
city: Bethesda
country: United States
facility: Warren G. Magnuson Clinical Center (CC)
state: Maryland
Study officials:
References:
citation: Sietsema KE, Cooper DM, Perloff JK, Rosove MH, Child JS, Canobbio MM, Whipp BJ, Wasserman K. Dynamics of oxygen uptake during exercise in adults with cyanotic congenital heart disease. Circulation. 1986 Jun;73(6):1137-44. doi: 10.1161/01.cir.73.6.1137.
citation: Hughson RL. Alterations in the oxygen deficit-oxygen debt relationships with beta-adrenergic receptor blockade in man. J Physiol. 1984 Apr;349:375-87. doi: 10.1113/jphysiol.1984.sp015161.
citation: Powers SK, Dodd S, Beadle RE. Oxygen uptake kinetics in trained athletes differing in VO2max. Eur J Appl Physiol Occup Physiol. 1985;54(3):306-8. doi: 10.1007/BF00426150.