scholarly journals Physiological Responses to Treadmill Running With Body Weight Support in Hypoxia Compared With Normoxia

2018 ◽  
Vol 27 (3) ◽  
pp. 224-229 ◽  
Author(s):  
Ben J. Lee ◽  
Charles Douglas Thake
Keyword(s):  
Heart Rate ◽  
Body Weight ◽  
Metabolic Response ◽  
Treadmill Running ◽  
Positive Pressure ◽  
Lower Body ◽  
Physiological Strain ◽  
Sports Clubs ◽  
Lower Body Positive Pressure ◽  
Body Positive

Context: Anecdotal reports suggest elite sports clubs combine lower-body positive-pressure rehabilitation with a hypoxic stimulus to maintain or increase physiological and metabolic strain, which are reduced during lower-body positive pressure. However, the effects of hypoxia on cardiovascular and metabolic response during lower-body positive-pressure rehabilitation are unknown. Objective: Evaluate the use of normobaric hypoxia as a means to increase physiological strain during body-weight-supported (BWS) running. Design: Crossover study. Setting: Controlled laboratory. Participants: Seven familiarized males (mean (SD): age, 20 (1) y; height, 1.77 (0.05) m; mass, 69.4 (5.1) kg; hemoglobin, 15.2 (0.8) g·dL−1) completed a normoxic and hypoxic (fraction of inspired oxygen [O2] = 0.14) trial, during which they ran at 8 km·h−1 on an AlterG™ treadmill with 0%, 30%, and 60% BWS in a randomized order for 10 minutes interspersed with 5 minutes of recovery. Main Outcome Measures: Arterial O2 saturation, heart rate, O2 delivery, and measurements of metabolic strain via indirect calorimetry. Results: Hypoxic exercise reduced hemoglobin O2 saturation and elevated heart rate at each level of BWS compared with normoxia. However, the reduction in hemoglobin O2 saturation was attenuated at 60% BWS compared with 0% and 30%, and consequently, O2 delivery was better maintained at 60% BWS. Conclusion: Hypoxia is a practically useful means of increasing physiological strain during BWS rehabilitation. In light of the maintenance of hemoglobin O2 saturation and O2 delivery at increasing levels of BWS, fixed hemoglobin saturations rather than a fixed altitude are recommended to maintain an aerobic stimulus.

scholarly journals Effect of Uphill Running on VO2, Heart Rate and Lactate Accumulation on Lower Body Positive Pressure Treadmills

Sports ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 51
Author(s):  
Daniel Fleckenstein ◽  
Olaf Ueberschär ◽  
Jan C. Wüstenfeld ◽  
Peter Rüdrich ◽  
Bernd Wolfarth
Keyword(s):  
Heart Rate ◽  
Body Weight ◽  
Body Weight Support ◽  
Positive Pressure ◽  
Lower Body ◽  
Lactate Accumulation ◽  
Biomechanical Stress ◽  
Lower Body Positive Pressure ◽  
Weight Support ◽  
Body Positive

Lower body positive pressure treadmills (LBPPTs) as a strategy to reduce musculoskeletal load are becoming more common as part of sports conditioning, although the requisite physiological parameters are unclear. To elucidate their role, ten well-trained runners (30.2 ± 3.4 years; VO2max: 60.3 ± 4.2 mL kg−1 min−1) ran at 70% of their individual velocity at VO2max (vVO2max) on a LBPPT at 80% body weight support (80% BWSet) and 90% body weight support (90% BWSet), at 0%, 2% and 7% incline. Oxygen consumption (VO2), heart rate (HR) and blood lactate accumulation (LA) were monitored. It was found that an increase in incline led to increased VO2 values of 6.8 ± 0.8 mL kg−1 min−1 (0% vs. 7%, p < 0.001) and 5.4 ± 0.8 mL kg−1 min−1 (2% vs. 7%, p < 0.001). Between 80% BWSet and 90% BWSet, there were VO2 differences of 3.3 ± 0.2 mL kg−1 min−1 (p < 0.001). HR increased with incline by 12 ± 2 bpm (0% vs. 7%, p < 0.05) and 10 ± 2 bpm (2% vs. 7%, p < 0.05). From 80% BWSet to 90% BWSet, HR increases of 6 ± 1 bpm (p < 0.001) were observed. Additionally, LA values showed differences of 0.10 ± 0.02 mmol l−1 between 80% BWSet and 90% BWSet. Those results suggest that on a LBPPT, a 2% incline (at 70% vVO2max) is not yet sufficient to produce significant physiological changes in VO2, HR and LA—as opposed to running on conventional treadmills, where significant changes are measured. However, a 7% incline increases VO2 and HR significantly. Bringing together physiological and biomechanical factors from previous studies into this practical context, it appears that a 7% incline (at 80% BWSet) may be used to keep VO2 and HR load unchanged as compared to unsupported running, while biomechanical stress is substantially reduced.

Effects of posture on peripheral vascular responses to lower body positive pressure

2007 ◽  
Vol 293 (1) ◽  
pp. H670-H676 ◽  
Author(s):  
Takeshi Nishiyasu ◽  
Shigeko Hayashida ◽  
Asami Kitano ◽  
Kei Nagashima ◽  
Masashi Ichinose
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Forearm Blood Flow ◽  
Positive Pressure ◽  
Upper Limbs ◽  
Lower Body ◽  
Peripheral Vascular ◽  
Vascular Responses ◽  
Lower Body Positive Pressure ◽  
Body Positive

We tested the hypothesis that peripheral vascular responses (in the lower and upper limbs) to application of lower body positive pressure (LBPP) are dependent on the posture of the subjects. We measured heart rate, stroke volume, mean arterial pressure, leg and forearm blood flow (using the Doppler ultrasound technique), and leg (LVC) and forearm (FVC) vascular conductance in 11 subjects (9 men, 2 women) without and with LBPP (25 and 50 mmHg) in supine and upright postures. Mean arterial pressure increased in proportion to increases in LBPP and was greater in supine than in upright subjects. Heart rate was unchanged when LBPP was applied to supine subjects but was reduced in upright ones. Leg blood flow and LVC were both reduced by LBPP in supine subjects [LVC: 4.8 (SD 4.0), 3.6 (SD 3.5), and 1.4 (SD 1.8) ml·min−1·mmHg−1 before LBPP and during 25 and 50 mmHg LBPP, respectively; P < 0.05] but were increased in upright ones [LVC: 2.0 (SD 1.2), 3.4 (SD 3.4), and 3.0 (SD 2.0) ml·min−1·mmHg−1, respectively; P < 0.05]. Forearm blood flow and FVC both declined when LBPP was applied to supine subjects [FVC: 1.3 (SD 0.6), 1.0 (SD 0.4), and 0.9 (SD 0.6) ml· min−1·mmHg−1, respectively; P < 0.05] but remained unchanged in upright ones [FVC: 0.7 (SD 0.4), 0.7 (SD 0.4), and 0.6 (SD 0.5) ml·min−1·mmHg−1, respectively]. Together, these findings indicate that the leg vascular response to application of LBPP is posture dependent and that the response differs in the lower and upper limbs when subjects assume an upright posture.

scholarly journals Alterations in the Rate of Limb Movement Using a Lower Body Positive Pressure Treadmill Do Not Influence Respiratory Rate or Phase III Ventilation

2015 ◽  
Vol 2015 ◽  
pp. 1-4
Author(s):  
Michael J. Buono ◽  
Marissa Burnsed-Torres ◽  
Bethany Hess ◽  
Kristine Lopez ◽  
Catherine Ortiz ◽  
...  
Keyword(s):  
Body Weight ◽  
Metabolic Rate ◽  
Submaximal Exercise ◽  
Limb Movement ◽  
Phase Iii ◽  
Positive Pressure ◽  
Lower Body ◽  
Step Frequency ◽  
Lower Body Positive Pressure ◽  
Body Positive

The purpose of this study was to determine the effect of alterations in rate of limb movement on Phase III ventilation during exercise, independent of metabolic rate, gait style, and treadmill incline. Subjects completed five submaximal exercise bouts on a lower body positive pressure treadmill (AlterG P 200). The percent body weight for the five exercise bouts was 100, 87, 75, 63, and 50% and each was matched for carbon dioxide production (VCO2). Naturally, to match theVCO2while reducing the body weight up to 50% of normal required a significant increase in the treadmill speed from3.0±0.1to4.1±0.2mph, which resulted in a significant(P<0.05)increase in the mean step frequency (steps per minute) from118±10at 3 mph (i.e., 100% of body weight) to133±6at 4.1 mph (i.e., 50% of body weight). The most important finding was that significant increases in step frequency did not significantly alter minute ventilation or respiratory rate. Such results do not support an important role for the rate of limb movement in Phase III ventilation during submaximal exercise, when metabolic rate, gait style, and treadmill incline are controlled.

Ambulation in simulated fractional gravity using lower body positive pressure: cardiovascular safety and gait analyses

2006 ◽  
Vol 101 (3) ◽  
pp. 771-777 ◽  
Author(s):  
Adnan Cutuk ◽  
Eli R. Groppo ◽  
Edward J. Quigley ◽  
Klane W. White ◽  
Robert A. Pedowitz ◽  
...  
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Ambient Pressure ◽  
Cardiovascular Responses ◽  
Microvascular Blood Flow ◽  
Positive Pressure ◽  
Lower Body ◽  
Lower Body Positive Pressure ◽  
Body Positive ◽  
Gait Mechanics

The purpose of this study is to assess cardiovascular responses to lower body positive pressure (LBPP) and to examine the effects of LBPP unloading on gait mechanics during treadmill ambulation. We hypothesized that LBPP allows comfortable unloading of the body with minimal impact on the cardiovascular system and gait parameters. Fifteen healthy male and female subjects (22–55 yr) volunteered for the study. Nine underwent noninvasive cardiovascular studies while standing and ambulating upright in LBPP, and six completed a gait analysis protocol. During stance, heart rate decreased significantly from 83 ± 3 beats/min in ambient pressure to 73 ± 3 beats/min at 50 mmHg LBPP ( P < 0.05). During ambulation in LBPP at 3 mph (1.34 m/s), heart rate decreased significantly from 99 ± 4 beats/min in ambient pressure to 84 ± 2 beats/min at 50 mmHg LBPP ( P < 0.009). Blood pressure, brain oxygenation, blood flow velocity through the middle cerebral artery, and head skin microvascular blood flow did not change significantly with LBPP. As allowed by LBPP, ambulating at 60 and 20% body weight decreased ground reaction force ( P < 0.05), whereas knee and ankle sagittal ranges of motion remained unaffected. In conclusion, ambulating in LBPP has no adverse impact on the systemic and head cardiovascular parameters while producing significant unweighting and minimal alterations in gait kinematics. Therefore, ambulating within LBPP is potentially a new and safe rehabilitation tool for patients to reduce loads on lower body musculoskeletal structures while preserving gait mechanics.

scholarly journals Effects of Lower Body Positive Pressure on Cardiovascular Responses During Walking in Elderly Women

2013 ◽  
pp. 653-662 ◽  
Author(s):  
T. SOTA ◽  
S. MATSUO ◽  
Y. UCHIDA ◽  
H. HAGINO ◽  
Y. KAWAI
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Systolic Blood Pressure ◽  
Elderly Women ◽  
Cardiovascular Responses ◽  
Elderly Subjects ◽  
Positive Pressure ◽  
Lower Body ◽  
Lower Body Positive Pressure ◽  
Body Positive

This study was undertaken to investigate the effects of lower body positive pressure (LBPP) on cardiovascular responses during a 15-min walking trial in young (22.1±0.4 years) and elderly women (67.8±1.1 years). The application of 20 mm Hg LBPP reduced ground reaction forces by 31.2±0.5 kgw in both groups. We hypothesized that cardiovascular responses to LBPP during walking were different between the young and elderly subjects. Applying 20 mm Hg of LBPP increased diastolic and mean blood pressure but not systolic blood pressure in both groups. LBPP-induced reduction in heart rate (HR) occurred more quickly in the young group compared to the elderly group (p<0.05). Applying LBPP also decreased double product (systolic blood pressure x HR) in both groups, suggesting that LBPP reduces myocardial oxygen consumption during exercise. These results suggest that heart rate responses to LBPP during exercise vary with increasing age.

Baroreceptor-mediated suppression of osmotically stimulated vasopressin in normal humans

1988 ◽  
Vol 65 (3) ◽  
pp. 1226-1230 ◽  
Author(s):  
S. R. Goldsmith
Keyword(s):  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Central Venous Pressure ◽  
Venous Pressure ◽  
Positive Pressure ◽  
Lower Body ◽  
Central Venous ◽  
Lower Body Positive Pressure ◽  
Body Positive

Increases in central venous pressure and arterial pressure have been reported to have variable effects on normal arginine vasopressin (AVP) levels in healthy humans. To test the hypothesis that baroreceptor suppression of AVP secretion might be more likely if AVP were subjected to a prior osmotic stimulus, we investigated the response of plasma AVP to increased central venous pressure and mean arterial pressure after hypertonic saline in six normal volunteers. Plasma AVP, serum osmolality, heart rate, central venous pressure, mean arterial pressure, and pulse pressure were assessed before and after a 0.06 ml.kg-1.min-1-infusion of 5% saline give over 90 min and then after 10 min of 30 degrees head-down tilt and 10 min of head-down tilt plus lower-body positive pressure. Hypertonic saline increased plasma AVP. After head-down tilt, which did not change heart rate, pulse pressure, or mean arterial pressure but did increase central venous pressure, plasma AVP fell. Heart rate, pulse pressure, and central venous pressure were unchanged from head-down tilt values during lower-body positive pressure, whereas mean arterial pressure increased. Plasma AVP during lower-body positive pressure was not different from that during tilt. Osmolality increased during the saline infusion but was stable throughout the remainder of the study. These data therefore suggest that an osmotically stimulated plasma AVP level can be suppressed by baroreflex activation. Either the low-pressure cardiopulmonary receptors (subjected to a rise in central venous pressure during head-down tilt) or the sinoaortic baroreceptors (subjected to hydrostatic effects during head-down tilt) could have been responsible for the suppression of AVP.(ABSTRACT TRUNCATED AT 250 WORDS)

Metabolic Cost and Fuel Utilization of Normal and Lower Body Positive Pressure Treadmill Running

2016 ◽  
Vol 48 ◽  
pp. 212
Author(s):  
James Hokanson ◽  
Deborah Van Langen ◽  
Erik Lind ◽  
Larissa True ◽  
Saige Hupman
Keyword(s):  
Metabolic Cost ◽  
Treadmill Running ◽  
Positive Pressure ◽  
Lower Body ◽  
Fuel Utilization ◽  
Lower Body Positive Pressure ◽  
Body Positive

scholarly journals Cardiorespiratory and metabolic responses to exercise testing during lower-body positive pressure running

2020 ◽  
Vol 128 (4) ◽  
pp. 778-784
Author(s):  
Tim Brüssau ◽  
Robert Oehring ◽  
Stephan B. Felix ◽  
Marcus Dörr ◽  
Martin Bahls
Keyword(s):  
Body Weight ◽  
Perceived Exertion ◽  
Pulse Wave ◽  
Disease Risk ◽  
Rating Of Perceived Exertion ◽  
Cardiometabolic Disease ◽  
Positive Pressure ◽  
Lower Body ◽  
Lower Body Positive Pressure ◽  
Body Positive

Exercise reduces the future cardiometabolic disease risk. However, not everyone can participate in routine physical activity because of obesity or orthopedic impairments. Body weight-supported (BWS) exercise may be an option for these individuals. Unfortunately, very little data are available with regard to BWS running in untrained healthy individuals. Yet, this information is important to assess the potential use of lower-body positive pressure (LBPP) treadmill running for the prevention of cardiometabolic disease. Twenty healthy but untrained participants (10 females, mean age 31.5 yr) were included in this study. Participants completed two exercise tests (one with 100% and one with 60% body wt) in randomized order on a LBPP treadmill. Expired gas data and heart rate (HR) were collected continuously. Blood lactate, blood pressure (BP), pulse wave velocity (PWV), and rating of perceived exertion (RPE) were measured during a 2-min break after each stage. Oxygen uptake increased significantly independent of BWS but was lower with BWS. Furthermore, we identified a significant correlation between HR and RPE independent of BWS. BP and PWV showed a large heterogeneity in response to BWS. The lower O2 requirement when running with BWS may help untrained individuals to adapt to an exercise regimen. Future research needs to explore the heterogenetic response of blood pressure and pulse wave velocity to LBPP BWS between individuals. NEW & NOTEWORTHY Lower-body positive pressure body weight-supported exercise has a lower metabolic and cardiovascular demand. Furthermore, heart rate and rating of perceived exertion are highly correlated independent of body weight support. Our data support the further examination of lower-body positive pressure exercise training for cardiovascular disease risk groups.

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