Hypoxic Training in Obese Patients (HYPOBESE)

September 15, 2014 updated by: Davide MALATESTA, University of Lausanne

Changes in Body Composition, Metabolic and Mechanical Responses to Hypoxic Walking Training in Obese Patients

By analyzing energetic and biomechanical basis of walking, and the subsequent changes induced by hypoxic vs normoxic training in obese individuals, it may optimize the use of walking in hypoxia to gain perspective for exercise prescription to set up training programs that aim to induce negative energy balance and to deal with weight management. However to the investigators knowledge, the analysis of changes in mechanics, energetics and efficiency of walking after continuous hypoxic training (CHT) has not been performed yet.

The aims of the present study were:

  1. Comparing the changes in body composition between continuous hypoxic training (CHT) and similar training in normoxia; e.g. continuous normoxic training (CNT) in obese subjects.
  2. Comparing the metabolic and energetics adaptations to CHT vs CNT.
  3. Finally, comparing the associated body-loss induced gait modification since walking intensity at spontaneous walking speed (Ss) is lower in CHT than in CNT.

Study Overview

Status

Unknown

Conditions

Intervention / Treatment

Detailed Description

Hypoxic training embraces different methods as "live high - train high" (LHTH) and "live high - train low" (LHTL); sleeping at altitude to gain the hematologic adaptations (increased erythrocyte volume) but training at sea level to maximize performance (maintenance of sea level training intensity and oxygen flux). The LHTL method can be accomplished via a number of methods and devices: natural/terrestrial altitude, nitrogen dilution, oxygen filtration and supplemental oxygen. Another method is the "live low - train high" (LLTH) method including intermittent hypoxic exposure at rest (IHE) or during intermittent hypoxic training sessions (IHT). Noteworthy, all supporting references were conducted with endurance elite athletes (i.e. cyclists, triathletes, cross-country skiers, runners, swimmers, kayakers, rowers) and there is an extensive literature relative both on LHTH and LHTL (Millet et al. 2010). Interestingly, very recently, the investigators research group proposed a new LLTH method (e.g. repeated sprints training in hypoxia; RSH) for team-sports players (Faiss et al. 2013). This lead to modify the nomenclature (Millet et al. 2013) and to divide LLTH method in four subsets; i.e. IHE, CHT (continuous >30 min low intensity training in hypoxia), IHT (interval-training in hypoxia) and RSH, based predominantly on different mechanisms; e.g. increased oxidative capacity (CHT), buffering capacity (IHT) or compensatory fiber-selective vasodilation (RSH). These new nomenclature and hypoxic methods open doors for investigating the use of different LLTH methods with other groups and for other purposes than the oxygen transport enhancement.

Several recent findings support the use of LLTH in obese subjects in terms of weight loss and/or cardiovascular and metabolic improvements (Kayser and Verges 2013). CHT [low intensity endurance exercise for 90 min at 60% of the heart rate at maximum aerobic capacity, 3 d week-1 for 8 weeks; fraction of inspired oxygen (FiO2) = 15%] in overweight subjects [body mass index (BMI) > 27] lead to larger (+1.1 kg) weight loss than similar training in normoxia. However, no difference was observed regarding BMI between the training modalities (Netzer et al. 2008). In a similar way, CHT (low intensity endurance exercise for 60 min at 65% of the heart rate at maximum aerobic capacity, 3 d week-1 for 4 weeks; FiO2 = 15%) induced similar increases in maximal oxygen consumption and endurance but larger improvements in respiratory quotient and lactate at the anaerobic threshold as well as in body composition than similar training in normoxia (Wiesner et al. 2010). Of interest is that the beneficial results were obtained despite lower training workload in hypoxia. This suggests that hypoxic training intensity can be lower in absolute value, at the spontaneous walking speed (Ss), also known as preferred or self-selected speed (e.g. the speed normally used during daily living activities). This appears to be an appropriate walking intensity for weight reduction programs aimed at inducing negative energy balance (Hills et al. 2006). A lower walking intensity is also likely more protective of the muscles/joints in obese patients with orthopaedic comorbidities. Finally, CHT was also shown (Haufe et al. 2008) to lead to larger change in body fat content, triglycerides, homeostasis assessment of insulin resistance (HOMA-Index), fasting insulin and area under the curve for insulin during an oral glucose tolerance test despite the lower absolute running intensity (1.4 and 1.7 W kg-1 in hypoxia and normoxia, respectively).

The net energy cost of level walking (NCw) represents the energy expenditure per distance unit only associated with walking movements. Previous studies reported higher absolute (J·m-1) and relative (i.e., normalized by body mass: J·kg-1·m-1) NCw in obese compared with normal body mass individuals (Browning et al. 2006; Peyrot et al. 2009), suggesting that the body mass is the main, but not the only, determinant of this lower economy of walking in obese subjects and that other factors may be involved in the higher NCw in these individuals(Browning et al. 2006; Peyrot et al. 2010; Peyrot et al. 2009). If body mass loss is an important method for the treatment of obesity and its associated co-morbidities and it may also be an important to investigate the effect of decreased body mass on gait pattern and mechanical external work (Wext) and their consequences on NCw in obese individuals. Walking is a fundamental movement pattern and the most common mode of physical activity. This form of locomotion may contribute significantly to weight management in overweight and obese subjects (Hill and Peters 1998; Jakicic et al. 2003; Pollock et al. 1971). Only one study showed that body mass reduction of 7% over 3 months resulted in gait kinematic changes (i.e., increases in walking speed, stride length and frequency, swing duration and decrease in cycle time, stance and double support time) in healthy adult obese women (BMI = 37 kg·m-2) (Plewa et al. 2007). However, these authors did not measure the NCw. More recently, Peyrot et al. (Peyrot et al. 2010) reported that, in healthy adolescent obese individuals, a 12-wk voluntary body mass reduction program (-6%) induced a reduction in NCw mainly associated with decreased body mass but also with changes in the biomechanical parameters of walking [i.e., a lesser lower limb muscle work required to rise the center of mass (CM) with Wext unchanged after intervention]. The authors hypothesized that the relation between the changes in absolute NCw and the changes in the biomechanical parameters might be explained by an increase in efficiency of muscle mechanical work with body mass loss as previously showed in cycling (Rosenbaum et al. 2003). Others studies (Messier et al. 2005; Messier et al. 2011), investigating only the effect of body mass loss (-3% and -10%, respectively) on biomechanical parameters of walking in non-healthy overweight and obese older adults with knee osteoarthritis, demonstrated that this body mass loss increased walking speed and reduced knee joint forces. Bariatric surgery may induce greater body mass loss (~30-40%) (Chaston et al. 2007) compared with exercise, diet or pharmaceutical interventions (~10%) (Franz et al. 2007) and may be considered as an interesting tool to maximize the effect of body mass loss on Wext and NCw in obese individuals and, thus, investigate the relationship between the gait pattern changes and the extra cost of walking in these subjects. Similarly, it would be of interest to investigate how the metabolic changes and body mass loss induced by CHT, potentially associated with an increased metabolic efficiency, would affect gait pattern and the extra cost of walking in obese subjects.

Study Type

Interventional

Enrollment (Anticipated)

30

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • Switzerland
    • Vaud
      • Lausanne, Vaud, Switzerland, 1015
        • Recruiting
        • Institute of Sport Sciences of the University of Lausanne
        • Contact:
        • Principal Investigator:
          • Davide Malatesta, Dr

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 40 years (Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Healthy and free of clinically significant orthopaedic, neurological, cardiovascular or respiratory conditions.
  • BMI > 30 kg/m^2.
  • Age > 18 yr.

Exclusion Criteria:

  • Age > 40 yr.
  • BMI < 35 kg/m^2.
  • Diabetes.
  • Neurological disorders, orthopaedic injury, history of falls and medications that provoke dizziness.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: CH training group
During 3 weeks (9 sessions; three sessions/wk), subject will performed 60 min walking at spontaneous walking speed in hypoxic (continuous hypoxic training, CHT; simulated altitude of 3000 m) condition in a single-blind fashion.
Other: Training
During 3 weeks (9 sessions; three sessions/wk), subject will performed 60 min walking at spontaneous walking speed in normoxic (continuous normoxic training; CNT) or hypoxic (continuous hypoxic training, CHT; simulated altitude of 3000 m) condition in a single-blind fashion. Both CNT and CHT sessions will be performed in an hypoxic chamber (ATS Altitude, Sydney, Australia) built in our laboratory at an altitude of 380 m (Lausanne, Switzerland). In order to blind subjects to altitude, the system will also run for normoxic training groups with a normoxic airflow into the chamber.
Active Comparator: CN training group
During 3 weeks (9 sessions; three sessions/wk), subject will performed 60 min walking at spontaneous walking speed in normoxic (continuous normoxic training; CNT) condition in a single-blind fashion.
Other: Training
During 3 weeks (9 sessions; three sessions/wk), subject will performed 60 min walking at spontaneous walking speed in normoxic (continuous normoxic training; CNT) or hypoxic (continuous hypoxic training, CHT; simulated altitude of 3000 m) condition in a single-blind fashion. Both CNT and CHT sessions will be performed in an hypoxic chamber (ATS Altitude, Sydney, Australia) built in our laboratory at an altitude of 380 m (Lausanne, Switzerland). In order to blind subjects to altitude, the system will also run for normoxic training groups with a normoxic airflow into the chamber.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Body composition and mass
Time Frame: Change from baseline at 5 weeks (e.g., baseline and 5th week after inclusion)
All subjects will undergo dual-energy X-ray absorptiometry (DEXA) and bio-impedance for measurements of body composition.
Change from baseline at 5 weeks (e.g., baseline and 5th week after inclusion)
Net energy cost of walking
Time Frame: Change from baseline at 5 weeks (e.g., baseline and 5th week after inclusion)
The subjects will be then asked to complete five 6 min level walking trials on the instrumented treadmill at five equally spaced speeds (0.55, 0.83, 1.11, 1.38 and 1.66 m/s), in randomized order. They will be allowed to establish their own preferred stride rate combination for each condition and will be given 5 min of rest between walking trials. During the walking trials, oxygen uptake (V˙O 2), carbon dioxide (CO2) output (V˙C O2) and ventilation (V˙ E) will be measured breath-by-breath (OxyconPro, Jaeger, Germany) and the volume and gases calibrations will be checked before each trial. Oxygen uptake values from the last 2 min will be averaged and normalized to body mass (V˙O 2, mlO2∙kg-1∙min-1). This value minus resting V'O2 was then divided by walking speed to obtain the net energy cost of walking (mlO2∙kg-1∙m-1).
Change from baseline at 5 weeks (e.g., baseline and 5th week after inclusion)
Mechanical external and internal work
Time Frame: Change from baseline at 5 weeks (e.g., baseline and 5th week after inclusion)
During steady metabolic state (i.e., the last 2 min of walking for each speed), the mechanical external (Wext) and internal (Wint) work changes of 20 consecutive walking steps will be determined with an instrumented treadmill (H-P-COSMOS Treadmill MCU2 EPROM 2.31), consisting of a treadmill mounted on four 3-D force sensors, following the methods described in detail by Cavagna (Cavagna 1975) and Willems et al. (1995).
Change from baseline at 5 weeks (e.g., baseline and 5th week after inclusion)
Efficiency
Time Frame: Change from baseline at 5 weeks (e.g., baseline and 5th week after inclusion)
Total mechanical work and efficiency. The total mass-specific muscular work per distance travelled (Wtot) will be calculated as the sum of Wext and Wint. The mechanical efficiency will be computed as the ratio between Wtot and net energy cost of walking.
Change from baseline at 5 weeks (e.g., baseline and 5th week after inclusion)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Blood samples (this measure is a composite)
Time Frame: Change from baseline at 5 weeks (e.g., baseline and 5th week after inclusion)
The blood samples were drawn at rest before (session 1) and after (session 12) the training program during fasting to determine total cholesterol (TC), high-density lipoprotein (HDL), low-density lipoprotein (LDL) and triglycerides (TG), leptin, total adiponectin, resistin, retinol-binding protein 4 (RBP4), plasma glucose and insulin concentrations (this measure is a composite).
Change from baseline at 5 weeks (e.g., baseline and 5th week after inclusion)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Lausanne

Collaborators

Centre Hospitalier Universitaire Vaudois
CHUV - Centre des Maladies Osseuses - Département de l'Appareil Locomoteur (DAL)

Investigators

  • Principal Investigator: Davide Malatesta, Dr, Institute of Sport Sciences of the University of Lausanne

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

September 1, 2014

Primary Completion (Anticipated)

July 1, 2015

Study Completion (Anticipated)

July 1, 2015

Study Registration Dates

First Submitted

September 10, 2014

First Submitted That Met QC Criteria

September 15, 2014

First Posted (Estimate)

September 16, 2014

Study Record Updates

Last Update Posted (Estimate)

September 16, 2014

Last Update Submitted That Met QC Criteria

September 15, 2014

Last Verified

September 1, 2014

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 136/14

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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