High Altitude Muscle Recovery (HAMR)

March 17, 2025 updated by: United States Army Research Institute of Environmental Medicine

Skeletal Muscle Recovery From Aerobic Exercise During Acute High Altitude Exposure When Consuming Carbohydrate Compared to Carbohydrate Plus Protein

To understand alterations in glycogen and molecular regulation of skeletal muscle glucose uptake, glycogen synthesis, and muscle protein recovery when consuming CHO (glucose) or CHO+PRO (glucose + whey) post-exercise during unacclimatized high altitude exposure, randomized crossover double blinded studies will be conducted in the hypobaric/hypoxic chamber at USARIEM Table 1. Briefly, the study consists of a 2 day baseline period at SL followed by two, 3 day trial periods (with the 3rd day being a testing day) at HA. The baseline is separated from trial 1 for a least a day, and trial 1 & 2 separated by at least 4 days. Volunteers will consume CHO (glucose) or CHO+PRO (glucose + whey) drinks post-exercise during unacclimatized high altitude exposure during the two trial periods. The order of the drinks will be randomized (using a random number generator such as randomizer.org) and kept by a study staff not directly involved in data collection to maintain blinding.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Dietary strategies that restore muscle glycogen and promote muscle repair and remodeling in recovery from exercise are needed to protect muscle mass and sustain performance during strenuous military operations conducted at high altitude (HA; > 2500 m elevation). However, most military personnel who operate at HA are native lowlanders and, thus, unacclimatized to the hypoxemia that occurs upon initial HA exposure. We demonstrated that acute HA exposure (within 5 hours) dysregulates peripheral glucose uptake and inhibits post-exercise muscle anabolism in lowlanders sojourning at 4,300 m. Our results suggest that traditional recommendations to consume solely carbohydrate immediately post-exercise to facilitate muscle recovery may be inadequate for lowlanders exercising within the first several hours of HA exposure. In a recent meta-analysis by our group, we reported that the effects of ingesting carbohydrate (CHO) compared to isocaloric carbohydrate plus protein (CHO+PRO) on muscle glycogen repletion were equivocal, yet the combined macronutrient blend confers an additional metabolic advantage than CHO alone because it stimulates muscle repair/remodeling by upregulating anabolic signaling and protein synthesis. Our findings suggest post-exercise CHO intake can be reduced in place of an isocaloric amount of PRO when exercising at HA without comprising glycogen repletion. However, whether CHO+PRO promotes post-exercise glycogen repletion and muscle anabolism as compared to CHO alone when peripheral glucose uptake and anabolic signaling are dysregulated with acute HA exposure has not been determined. This study aims to determine the effects of ingesting CHO or an isocaloric amount of CHO+PRO post-aerobic exercise on glycogen synthesis, molecular regulation of glucose uptake, storage, and muscle protein synthesis during acute HA exposure. This study will employ a randomized crossover double-blinded design and be conducted in the hypobaric/hypoxic chamber at USARIEM. A total of 10 healthy, physically active men and women between the ages of 18-39 years will be studied. Following 48 hours of controlled exercise and diet to normalize muscle glycogen stores, volunteers will report to the laboratory after a 10-h overnight fast. After a muscle biopsy is taken from the vastus lateralis at baseline, volunteers will be brought to HA (460 mmHg) conditions within the hypobaric/hypoxic chamber at USARIEM and complete a standardized glycogen depletion protocol on a cycle ergometer. After completing the glycogen depletion exercise a second muscle biopsy will be taken. Volunteers will then consume 1.2 g CHO/kg/h or 0.9 g CHO/kg/h + 0.3 g PRO/kg/h over a 3-h recovery period. A third and fourth biopsy will be taken 4 and 6 hours into recovery to characterize the molecular regulation of glucose uptake, glycogen synthesis, and muscle protein synthesis over time. Serial blood draws will be collected during each trial to assess endocrine and circulating substrate responses in CHO and CHO+PRO. Trials will be separated by a minimum of 4 days. The primary risks associated with this study include those associated with acute hypobaric hypoxia, exercise, muscle biopsies, and blood draws.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
8

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • 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 Locations

  • United States
    • Massachusetts
      • Natick, Massachusetts, United States, 01760
        • USARIEM

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Men and women aged 18 - 39 years
  • Physically active (exercise minimum 2-4 days per week)
  • Have supervisor approval (permanent party military and civilians at NSSC)
  • Willing to refrain from alcohol, nicotine products and dietary supplement use during the study
  • Females must have normal menstrual cycles between 26-32 days in duration; 5 menstrual cycles within the past 6 months; or using oral/hormonal contraceptive use which contains low-dose estrogen/progesterone to maintain continuous levels throughout the 28-day cycle (i.e., no placebos)
  • Only consume caffeine products during the study if provided by study staff

Exclusion Criteria:

  • Born at altitudes greater than 2,100 m (Subjects will inform the study team if they were born in Eagar AZ, Mammoth Lakes CA, CO, NM, UT, or WY).
  • Musculoskeletal injuries that compromise exercise capability
  • Metabolic or cardiovascular abnormalities, or gastrointestinal disorders (e.g. hypothyroidism, cardiovascular disease, Crohn's disease, etc.)
  • Taking medication that affects macronutrient metabolism and/or the ability to participate in strenuous exercise (e.g. thyroxine, beta blockers, insulin etc.)
  • Living in areas that are more than 1,200 m, or traveled to areas that are more than 1,200 m for five days or more within 2 months of data collection (e.g. Idaho Falls, ID; Denver, CO; etc.)
  • Prior diagnosis of high-altitude pulmonary edema or high-altitude cerebral edema
  • Presence of asthma or respiratory tract infections
  • Smoking or vaping (other forms of nicotine users, i.e., chewing tobacco will not be excluded; individuals who quit smoking or vaping for more than 90 days may be included)
  • Taking medications that interfere with oxygen delivery and transport (e.g. albuterol, EPO, etc.)
  • Hematocrit (HCT) <41% and Hemoglobin (HBG) <13.5 g/dL(Males), HCT <36% and HBG <12.0 g/dL (Females), and Sickle Cell Anemia/Trait
  • Whole blood donation within 8 weeks of the study
  • Unwilling or unable to only consume study diets or foods provided due to personal preference, dietary restrictions, and/or food allergies
  • Unwilling or unable to adhere to study physical restrictions (abstain from exercise or recreational activities i.e., pick-up basketball during the study procedures)
  • Pregnant, trying to become pregnant, and/or breastfeeding (results of urine pregnancy test or self-report for breastfeeding will be obtained before body composition testing)

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: Crossover Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Carbohydrate plus protein
Study beverages consumed over the initial 3 hours recovery phase from aerobic exercise, consuming 0.9g CHO/kg/hr + 0.3g PRO/kg/hr during high altitude exposure.
Dietary supplement: CHO+PRO
0.9 g CHO/kg/hr + 0.3 g PRO/kg/hr
Active Comparator: Carbohydrate
Study beverages consumed over the initial 3 hours recovery phase from aerobic exercise, consuming1.2g CHO/kg/hr during high altitude exposure.
Dietary supplement: CHO
1.2 g CHO/kg/hr

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Muscle Glycogen Concentrations
Time Frame: 6 hours
Determine the effects of of consuming a CHO (1.2 g CHO/kg/hr) compared to an isocaloric CHO+PRO (0.9 g CHO/kg/hr + 0.3 g PRO/kg/hr) supplement on post exercise muscle glycogen concentrations (umol/kg dry muscle weight) during the initial 6 hours of aerobic exercise recovery
6 hours
Phosphorylation status of rpS6
Time Frame: 6 hours
Determine the effects of of consuming a CHO (1.2 g CHO/kg/hr) compared to an isocaloric CHO+PRO (0.9 g CHO/kg/hr + 0.3 g PRO/kg/hr) supplement on post exercise muscle the fold change in the phosphorylation of rpS6 during the initial 6 hours of aerobic exercise recovery
6 hours

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
United States Army Research Institute of Environmental Medicine

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 (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
October 1, 2023

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 19, 2023

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 19, 2023

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
April 25, 2024

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 25, 2024

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
April 30, 2024

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
March 25, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 17, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
March 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 23-04H

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

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.

Cookie Settings

We use cookies to ensure that we give you the best experience on our website. For more details carefully read our Privacy and Cookies Policy. ...>>>You can change your preferences or withdraw your consent at any time by deleting the cookies from your website or computer as described in the policy. Please accept it and choose your preferences by ticking the corresponding boxes in the "Manage Settings" section below. Please carefully read our Terms of Service before you proceed with using any part of this website.
«Manage Settings