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Obesity and the Role of Short Duration Submaximal Work on Cardiovascular and Cerebral Hemodynamics.

Cavuoto LA, Maikala RV - PLoS ONE (2016)

Bottom Line: The non-obese group reached ~43% of their predicted maximal aerobic capacity as compared to ~34% in the obese group, with the non-obese working at a relatively higher workload and for more duration than the obese.The obese had elevated baseline heart rate and reduced whole-body oxygen uptake per body weight at baseline and task termination.However, both groups exhibited similar cerebral hemodynamics during recovery.

View Article: PubMed Central - PubMed

Affiliation: Industrial and Systems Engineering, University at Buffalo, Buffalo, New York, 14260, United States of America.

ABSTRACT
The objective of this study was to compare gas exchange, cardiac and cerebral hemodynamic responses between 10 non-obese and 10 obese men during submaximal work. With the increasing prevalence of obesity, there is a need to understand the impact of obesity on work-induced responses. Participants completed a step-wise incremental cycling until they reached 60% of their age-predicted maximum heart rate. Gas exchange, cardiac and pre-frontal cortex hemodynamic responses were simultaneously measured during rest, work, and recovery. The non-obese group reached ~43% of their predicted maximal aerobic capacity as compared to ~34% in the obese group, with the non-obese working at a relatively higher workload and for more duration than the obese. The obese had elevated baseline heart rate and reduced whole-body oxygen uptake per body weight at baseline and task termination. Other cardiac and cerebral responses, although increased from baseline, were similar between groups during submaximal effort. In the obese, during recovery oxygen uptake and heart-rate recovery were slowest; cardiac output and rate pressure product were greatest, and left ventricle ejection time was shortest. However, both groups exhibited similar cerebral hemodynamics during recovery. These finding imply that, irrespective of their low aerobic fitness, obesity does not impair myocardial performance and cerebrovascular function during graded submaximal work, however, recovery from a short duration of work was influenced by their fitness level. Since a majority of activities of daily living are performed at individual's submaximal level, understanding influence of obesity on submaximal work is critical.

No MeSH data available.


Related in: MedlinePlus

Physiological responses during incremental cycling scaled to the task duration.* represents a significant between-groups difference (p < 0.05) at the time point.
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pone.0153826.g002: Physiological responses during incremental cycling scaled to the task duration.* represents a significant between-groups difference (p < 0.05) at the time point.

Mentions: At task termination, the groups reached an average of 60.9 (3.3)% age-predicted maximum heart rate. However, the duration of the task in mean (SD) differed by group, with the non-obese terminating after 432 (67) seconds and the obese stopping after 330 (101) seconds (p = 0.016). All participants completed at least four minutes of cycling before reaching the stopping criteria. When gas exchange responses were normalized to task duration, the obese group exhibited higher VO2 compared to the non-obese group until 60% of task duration, at which point it dropped lower (see Fig 2B). The group level responses were significant at 20% and 100% of the task duration. VO2 per kg of body mass was equivalent between groups from 0% to 40% of task duration and then the non-obese group had more than 50% higher uptake (see Fig 2C).


Obesity and the Role of Short Duration Submaximal Work on Cardiovascular and Cerebral Hemodynamics.

Cavuoto LA, Maikala RV - PLoS ONE (2016)

Physiological responses during incremental cycling scaled to the task duration.* represents a significant between-groups difference (p < 0.05) at the time point.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4835079&req=5

pone.0153826.g002: Physiological responses during incremental cycling scaled to the task duration.* represents a significant between-groups difference (p < 0.05) at the time point.
Mentions: At task termination, the groups reached an average of 60.9 (3.3)% age-predicted maximum heart rate. However, the duration of the task in mean (SD) differed by group, with the non-obese terminating after 432 (67) seconds and the obese stopping after 330 (101) seconds (p = 0.016). All participants completed at least four minutes of cycling before reaching the stopping criteria. When gas exchange responses were normalized to task duration, the obese group exhibited higher VO2 compared to the non-obese group until 60% of task duration, at which point it dropped lower (see Fig 2B). The group level responses were significant at 20% and 100% of the task duration. VO2 per kg of body mass was equivalent between groups from 0% to 40% of task duration and then the non-obese group had more than 50% higher uptake (see Fig 2C).

Bottom Line: The non-obese group reached ~43% of their predicted maximal aerobic capacity as compared to ~34% in the obese group, with the non-obese working at a relatively higher workload and for more duration than the obese.The obese had elevated baseline heart rate and reduced whole-body oxygen uptake per body weight at baseline and task termination.However, both groups exhibited similar cerebral hemodynamics during recovery.

View Article: PubMed Central - PubMed

Affiliation: Industrial and Systems Engineering, University at Buffalo, Buffalo, New York, 14260, United States of America.

ABSTRACT
The objective of this study was to compare gas exchange, cardiac and cerebral hemodynamic responses between 10 non-obese and 10 obese men during submaximal work. With the increasing prevalence of obesity, there is a need to understand the impact of obesity on work-induced responses. Participants completed a step-wise incremental cycling until they reached 60% of their age-predicted maximum heart rate. Gas exchange, cardiac and pre-frontal cortex hemodynamic responses were simultaneously measured during rest, work, and recovery. The non-obese group reached ~43% of their predicted maximal aerobic capacity as compared to ~34% in the obese group, with the non-obese working at a relatively higher workload and for more duration than the obese. The obese had elevated baseline heart rate and reduced whole-body oxygen uptake per body weight at baseline and task termination. Other cardiac and cerebral responses, although increased from baseline, were similar between groups during submaximal effort. In the obese, during recovery oxygen uptake and heart-rate recovery were slowest; cardiac output and rate pressure product were greatest, and left ventricle ejection time was shortest. However, both groups exhibited similar cerebral hemodynamics during recovery. These finding imply that, irrespective of their low aerobic fitness, obesity does not impair myocardial performance and cerebrovascular function during graded submaximal work, however, recovery from a short duration of work was influenced by their fitness level. Since a majority of activities of daily living are performed at individual's submaximal level, understanding influence of obesity on submaximal work is critical.

No MeSH data available.


Related in: MedlinePlus