Journal of Sports Sciences
ISSN: 0264-0414 (Print) 1466-447X (Online) Journal homepage: http://www.tandfonline.com/loi/rjsp20
Acute moderate exercise does not attenuate cardiometabolic function associated with a bout of prolonged sitting Amanda M. Younger, Robert W. Pettitt, Patrick J. Sexton, William J. Maass & Cherie D. Pettitt To cite this article: Amanda M. Younger, Robert W. Pettitt, Patrick J. Sexton, William J. Maass & Cherie D. Pettitt (2015): Acute moderate exercise does not attenuate cardiometabolic function associated with a bout of prolonged sitting, Journal of Sports Sciences, DOI: 10.1080/02640414.2015.1068435 To link to this article: http://dx.doi.org/10.1080/02640414.2015.1068435
Published online: 17 Jul 2015.
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Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=rjsp20 Download by: [University of Exeter]
Date: 28 October 2015, At: 07:37
JOURNAL OF SPORTS SCIENCES, 2015 http://dx.doi.org/10.1080/02640414.2015.1068435
Acute moderate exercise does not attenuate cardiometabolic function associated with a bout of prolonged sitting Amanda M. Younger, Robert W. Pettitt, Patrick J. Sexton, William J. Maass and Cherie D. Pettitt
Downloaded by [University of Exeter] at 07:37 28 October 2015
Viola Holbrook Research Laboratory, Department of Human Performance, Minnesota State University Mankato, Mankato, MN 56001, USA
ABSTRACT
ARTICLE HISTORY
Epidemiological studies suggest that prolonged sitting increases all-cause mortality; yet, physiological causes underpinning prolonged sitting remain elusive. We evaluated cardiometabolic function during prolonged sitting (5 h) in 10 adults with and without 30 min of moderate exercise leading up to the sitting. Mean arterial blood pressure (MAP), heart rate (HR) and posterior tibial artery blood velocity were measured at baseline and every hour subsequently. Blood glucose was measured at baseline, 3 and 5 h, with consumption of a caloric beverage at 1 h. Seated MAP and HR values were ~17 mmHg (P < 0.001) and ~4 bpm (P < 0.05) higher for the moderate exercise versus sitting conditions. A ~ 4 cm·s−1 (16%) (P < 0.05) decline in posterior tibial artery blood velocity from prolonged sitting was observed, with no benefit conferred from moderate exercise. Postprandial glucose metabolism was not different between conditions (P > 0.05). We conclude prolonged sitting may be related to decreased posterior tibial artery blood velocity. Moreover, an acute bout of moderate exercise does not seem to attenuate cardiometabolic function during prolonged sitting in healthy, young adults.
Accepted 28 June 2015
Introduction
Methods
Prolonged sitting has emerged as a new purported risk factor for all-cause mortality (Owen, Salmon, Koohsari, Turrell, & Giles-Corti, 2014). Epidemiological research indicates that prolonged sitting is a comorbidity linked with chronic diseases such as type 2 diabetes, cardiovascular disease and numerous other metabolic disorders (Healy et al., 2008; Healy, Matthews, Dunstan, Winkler, & Owen, 2011). Prolonged sitting may lead to higher all-cause mortality risk, independent of physical activity (Van Der Ploeg, Chey, Korda, Banks, & Bauman, 2012). The biological factors associated with prolonged sitting remain elusive, but prevalence of atherosclerosis in the legs is a purported comorbidity (Trinity et al., 2014). Exercise may decrease mean arterial blood pressure (MAP) and increase resting arterial diameter, hence decreasing blood velocity and flow (Dinenno et al., 2001). Thus, an acute exercise bout may thwart negative vascular responses to prolonged sitting. The acute effects of a moderate physical activity bout followed by prolonged sitting on glucose, MAP and posterior tibial artery blood velocity in healthy individuals have not been investigated. We evaluated these cardiometabolic parameters in response to prolonged sitting with and without a preceding moderate exercise bout. We hypothesised a single bout of moderate exercise would attenuate these adverse cardiometabolic responses associated with prolonged sitting.
Participants
CONTACT Cherie D. Pettitt © 2015 Taylor & Francis
[email protected]
KEYWORDS
Αccelerometer; prolonged sitting; Doppler ultrasound; posterior tibial artery blood velocity
A convenience sample of 10 healthy, normotensive young adults (six males, four females; age 22.2 ± 1.3 years; body mass = 78 ± 12 kg; height = 175.5 ± 9.0 cm; BMI = 25 ± 2 kg·m−2) were recruited. Eligible participants were non-smokers who did not have a history of cardiovascular disease, diabetes or other medical conditions that prevented them from completing a maximal oxygen uptake (VO2max) test. Informed consent was obtained and procedures were pre-approved by our university’s institutional review board for human subjects.
Preliminary testing The total experiment required three laboratory visits: a day of preliminary testing and instruction followed by two prolonged sitting trials. The preliminary test day involved acquiring informed consent, conducting health history screening and administering a graded exercise test for the determination of gas exchange threshold (GET) and VO2max. The participants were instructed on the procedures of the two sitting trials and were asked to avoid strenuous exercise two days prior to each laboratory visit. The graded exercise test included single-minute stages of advancing power output on a cycle ergometer (Monarch, model 874E, Sweden), until participants failed to sustain preferred cadence for >10 s despite strong, verbal encourage-
Minnesota State University, 1400 Highland Center, Mankato, MN 56001, USA.
2
A. M. YOUNGER ET AL.
Downloaded by [University of Exeter] at 07:37 28 October 2015
ment. Stages for the graded exercise test were calculated using: Wpeak (W·min−1) ÷ 10 min, where the estimated power evoking VO2max (Wpeak) was determined using a series of regression equations (Sedgemen, Dalleck, Clark, Jamnick, & Pettitt, 2013), and the duration of 10 min was the desired graded exercise test duration (Kirkeberg, Dalleck, Kamphoff, & Pettitt, 2011). The GET and power evoking gas exchange threshold (WGET) parameters were determined using the v-slope method (Beaver, Wasserman, & Whipp, 1986; Pettitt, Clark, Ebner, Sedgeman, & Murray, 2013). Expired gases (15 s sampling) (Robergs, Dwyer, & Astorino, 2010) were collected via indirect spirometry (TrueOne, Parvomedics, Sandy, UT). The WGET parameter was used to prescribe the moderate exercise bout at 90% WGET. At the preliminary visit, participants also were fitted with an accelerometer (ActiGraph accelerometer wGT3X-BT, Pensacola, FL, USA), which they wore for 48 h prior to each sitting trial. Participants were asked to fast for ≥9 h prior to each visit (Dunstan et al., 2012; Healy et al., 2007).
Accelerometer data Physical activity levels were measured objectively via accelerometers. The accelerometer was strapped firmly around the participant’s torso oriented over the right anterior superior iliac spine of the pelvis. Accelerometers were worn to determine whether cardiometabolic responses to our prolonged sitting trials were confounded by different physical activity levels for 48 h leading up to the trials (Dunstan et al., 2012). Participants were instructed to wear the accelerometer during all waking hours except when bathing. Triaxial data were recorded in 60 s epochs along with steps and inclinometry. Accelerometer counts of
ISSN: 0264-0414 (Print) 1466-447X (Online) Journal homepage: http://www.tandfonline.com/loi/rjsp20
Acute moderate exercise does not attenuate cardiometabolic function associated with a bout of prolonged sitting Amanda M. Younger, Robert W. Pettitt, Patrick J. Sexton, William J. Maass & Cherie D. Pettitt To cite this article: Amanda M. Younger, Robert W. Pettitt, Patrick J. Sexton, William J. Maass & Cherie D. Pettitt (2015): Acute moderate exercise does not attenuate cardiometabolic function associated with a bout of prolonged sitting, Journal of Sports Sciences, DOI: 10.1080/02640414.2015.1068435 To link to this article: http://dx.doi.org/10.1080/02640414.2015.1068435
Published online: 17 Jul 2015.
Submit your article to this journal
Article views: 118
View related articles
View Crossmark data
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=rjsp20 Download by: [University of Exeter]
Date: 28 October 2015, At: 07:37
JOURNAL OF SPORTS SCIENCES, 2015 http://dx.doi.org/10.1080/02640414.2015.1068435
Acute moderate exercise does not attenuate cardiometabolic function associated with a bout of prolonged sitting Amanda M. Younger, Robert W. Pettitt, Patrick J. Sexton, William J. Maass and Cherie D. Pettitt
Downloaded by [University of Exeter] at 07:37 28 October 2015
Viola Holbrook Research Laboratory, Department of Human Performance, Minnesota State University Mankato, Mankato, MN 56001, USA
ABSTRACT
ARTICLE HISTORY
Epidemiological studies suggest that prolonged sitting increases all-cause mortality; yet, physiological causes underpinning prolonged sitting remain elusive. We evaluated cardiometabolic function during prolonged sitting (5 h) in 10 adults with and without 30 min of moderate exercise leading up to the sitting. Mean arterial blood pressure (MAP), heart rate (HR) and posterior tibial artery blood velocity were measured at baseline and every hour subsequently. Blood glucose was measured at baseline, 3 and 5 h, with consumption of a caloric beverage at 1 h. Seated MAP and HR values were ~17 mmHg (P < 0.001) and ~4 bpm (P < 0.05) higher for the moderate exercise versus sitting conditions. A ~ 4 cm·s−1 (16%) (P < 0.05) decline in posterior tibial artery blood velocity from prolonged sitting was observed, with no benefit conferred from moderate exercise. Postprandial glucose metabolism was not different between conditions (P > 0.05). We conclude prolonged sitting may be related to decreased posterior tibial artery blood velocity. Moreover, an acute bout of moderate exercise does not seem to attenuate cardiometabolic function during prolonged sitting in healthy, young adults.
Accepted 28 June 2015
Introduction
Methods
Prolonged sitting has emerged as a new purported risk factor for all-cause mortality (Owen, Salmon, Koohsari, Turrell, & Giles-Corti, 2014). Epidemiological research indicates that prolonged sitting is a comorbidity linked with chronic diseases such as type 2 diabetes, cardiovascular disease and numerous other metabolic disorders (Healy et al., 2008; Healy, Matthews, Dunstan, Winkler, & Owen, 2011). Prolonged sitting may lead to higher all-cause mortality risk, independent of physical activity (Van Der Ploeg, Chey, Korda, Banks, & Bauman, 2012). The biological factors associated with prolonged sitting remain elusive, but prevalence of atherosclerosis in the legs is a purported comorbidity (Trinity et al., 2014). Exercise may decrease mean arterial blood pressure (MAP) and increase resting arterial diameter, hence decreasing blood velocity and flow (Dinenno et al., 2001). Thus, an acute exercise bout may thwart negative vascular responses to prolonged sitting. The acute effects of a moderate physical activity bout followed by prolonged sitting on glucose, MAP and posterior tibial artery blood velocity in healthy individuals have not been investigated. We evaluated these cardiometabolic parameters in response to prolonged sitting with and without a preceding moderate exercise bout. We hypothesised a single bout of moderate exercise would attenuate these adverse cardiometabolic responses associated with prolonged sitting.
Participants
CONTACT Cherie D. Pettitt © 2015 Taylor & Francis
[email protected]
KEYWORDS
Αccelerometer; prolonged sitting; Doppler ultrasound; posterior tibial artery blood velocity
A convenience sample of 10 healthy, normotensive young adults (six males, four females; age 22.2 ± 1.3 years; body mass = 78 ± 12 kg; height = 175.5 ± 9.0 cm; BMI = 25 ± 2 kg·m−2) were recruited. Eligible participants were non-smokers who did not have a history of cardiovascular disease, diabetes or other medical conditions that prevented them from completing a maximal oxygen uptake (VO2max) test. Informed consent was obtained and procedures were pre-approved by our university’s institutional review board for human subjects.
Preliminary testing The total experiment required three laboratory visits: a day of preliminary testing and instruction followed by two prolonged sitting trials. The preliminary test day involved acquiring informed consent, conducting health history screening and administering a graded exercise test for the determination of gas exchange threshold (GET) and VO2max. The participants were instructed on the procedures of the two sitting trials and were asked to avoid strenuous exercise two days prior to each laboratory visit. The graded exercise test included single-minute stages of advancing power output on a cycle ergometer (Monarch, model 874E, Sweden), until participants failed to sustain preferred cadence for >10 s despite strong, verbal encourage-
Minnesota State University, 1400 Highland Center, Mankato, MN 56001, USA.
2
A. M. YOUNGER ET AL.
Downloaded by [University of Exeter] at 07:37 28 October 2015
ment. Stages for the graded exercise test were calculated using: Wpeak (W·min−1) ÷ 10 min, where the estimated power evoking VO2max (Wpeak) was determined using a series of regression equations (Sedgemen, Dalleck, Clark, Jamnick, & Pettitt, 2013), and the duration of 10 min was the desired graded exercise test duration (Kirkeberg, Dalleck, Kamphoff, & Pettitt, 2011). The GET and power evoking gas exchange threshold (WGET) parameters were determined using the v-slope method (Beaver, Wasserman, & Whipp, 1986; Pettitt, Clark, Ebner, Sedgeman, & Murray, 2013). Expired gases (15 s sampling) (Robergs, Dwyer, & Astorino, 2010) were collected via indirect spirometry (TrueOne, Parvomedics, Sandy, UT). The WGET parameter was used to prescribe the moderate exercise bout at 90% WGET. At the preliminary visit, participants also were fitted with an accelerometer (ActiGraph accelerometer wGT3X-BT, Pensacola, FL, USA), which they wore for 48 h prior to each sitting trial. Participants were asked to fast for ≥9 h prior to each visit (Dunstan et al., 2012; Healy et al., 2007).
Accelerometer data Physical activity levels were measured objectively via accelerometers. The accelerometer was strapped firmly around the participant’s torso oriented over the right anterior superior iliac spine of the pelvis. Accelerometers were worn to determine whether cardiometabolic responses to our prolonged sitting trials were confounded by different physical activity levels for 48 h leading up to the trials (Dunstan et al., 2012). Participants were instructed to wear the accelerometer during all waking hours except when bathing. Triaxial data were recorded in 60 s epochs along with steps and inclinometry. Accelerometer counts of
