Hypoxia
Conditions
Brief summary
The study will aim to describe and evaluate the effect of chronic beetroot juice supplementation on acute mountain sickness symptoms and exercise in a hypoxic environment. It is hypothesized that beetroot supplementation will decrease acute mountain sickness and increase exercise performance.
Interventions
DIETARY_SUPPLEMENTBeetroot Juice
DIETARY_SUPPLEMENTPlacebo
Sponsors
Bangor University
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
PREVENTION
Masking
TRIPLE (Subject, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
* Women only: Regular menstrual cycle or post-menopausal
Exclusion criteria
* Stayed at altitude above 2500m in the last 6 months * Traveled to altitude above 2500m in the last 2 months * Unable to give informed consent * Unstable medical condition.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Acute Mountain Sickness (AMS-C) as Assessed by the Environmental Symptoms Questionnaire. | Measured on the fifth day of supplementation with a six-hour exposure to hypoxia | Acute Cerebral Mountain Sickness score (AMS-C) calculated from the 11-item Environmental Symptoms Questionnaire (ESQ; Sampson et al., 1994). Participants rate the severity of each item from zero to five, and the ratings were multiplied by their factorial loadings and summed. Unabbreviated scale title: Acute Cerebral Mountain Sickness Abbreviated title: AMS-C Unit of measure: Scores on a scale Minimum value: 0 Maximum value: 5 Interpretation: Higher scores mean a worse outcome |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Hypoxic Exercise Performance as Assessed by Time to Exhaustion at 80% of Hypoxic V̇O2max Reserve. | Measured on the sixth day of supplementation | On day six of each supplementation protocol, participants completed a time to exhaustion test at 80% of their hypoxic V̇O2max reserve in acute hypoxia (FiO2 14.1%, equivalent 3225 m). Maximal exercise performance is defined as time to exhaustion (TTE) determined by the time from onset of test to task failure (volitional exhaustion or inability to maintain treadmill speed). |
Countries
United Kingdom
Participant flow
Pre-assignment details
1. Participants completed a baseline demographics visit including the following assessments: * Age * Height * Body mass * Blood pressure * Haemoglobin * Normoxic VO2max (maximal exercise) test 2. Participants then completed a minimum 48 h wash out 3. Participants completed a hypoxic VO2max test at 14.1% O2
Participants by arm
| Arm | Count |
|---|---|
| Nitrate First, Then Placebo Participants consumed a daily a beetroot shot for six days. Each shot will consist of: 1x70ml concentrated NO-3 shot of rich Beetroot juice (\
7mmol nitrate; Beet It, James White Drinks Ltd, Ipswich, UK).
10 day wash out
After a minimum 10-day wash-out, participants consumed a daily Nitrate-depleted beetroot shot for six days. Each shot will consist of 1x70ml nitrate-depleted beetroot Placebo shot (\
0.003mmol of nitrate; Beet It, James White Drinks Ltd, Ipswich, UK). | 13 |
| Placebo First, Then Nitrate Participants consumed a daily Nitrate-depleted beetroot shot for six days. Each shot will consist of 1x70ml nitrate-depleted beetroot Placebo shot (\
0.003mmol of nitrate; Beet It, James White Drinks Ltd, Ipswich, UK).
10 day wash out
After a minimum 10-day wash-out, participants consumed a daily a beetroot shot for six days. Each shot will consist of: 1x70ml concentrated NO-3 shot of rich Beetroot juice (\
7mmol nitrate; Beet It, James White Drinks Ltd, Ipswich, UK). | 10 |
| Total | 23 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| Wash Out (10 Days) | Adverse Event | 1 | 0 |
| Wash Out (10 Days) | Lost to Follow-up | 2 | 0 |
Baseline characteristics
| Characteristic | Placebo First, Then Nitrate | Total | Nitrate First, Then Placebo |
|---|---|---|---|
| Age, Categorical <=18 years | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical >=65 years | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical Between 18 and 65 years | 10 Participants | 23 Participants | 13 Participants |
| Age, Continuous | 22 years STANDARD_DEVIATION 4 | 22 years STANDARD_DEVIATION 4 | 21 years STANDARD_DEVIATION 4 |
| Maximal Aerobic Capacity | 50 ml/kg/min STANDARD_DEVIATION 6 | 51 ml/kg/min STANDARD_DEVIATION 6 | 53 ml/kg/min STANDARD_DEVIATION 6 |
| Race and Ethnicity Not Collected | — | 0 Participants | — |
| Sex: Female, Male Female | 0 Participants | 0 Participants | 0 Participants |
| Sex: Female, Male Male | 10 Participants | 23 Participants | 13 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 23 | 0 / 20 |
| other Total, other adverse events | 1 / 23 | 0 / 20 |
| serious Total, serious adverse events | 0 / 23 | 0 / 20 |
Outcome results
Primary
Acute Mountain Sickness (AMS-C) as Assessed by the Environmental Symptoms Questionnaire.
Acute Cerebral Mountain Sickness score (AMS-C) calculated from the 11-item Environmental Symptoms Questionnaire (ESQ; Sampson et al., 1994). Participants rate the severity of each item from zero to five, and the ratings were multiplied by their factorial loadings and summed. Unabbreviated scale title: Acute Cerebral Mountain Sickness Abbreviated title: AMS-C Unit of measure: Scores on a scale Minimum value: 0 Maximum value: 5 Interpretation: Higher scores mean a worse outcome
Time frame: Measured on the fifth day of supplementation with a six-hour exposure to hypoxia
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Nitrate | Acute Mountain Sickness (AMS-C) as Assessed by the Environmental Symptoms Questionnaire. | 0.36 scores on a scale | Standard Error 0.09 |
| Placebo | Acute Mountain Sickness (AMS-C) as Assessed by the Environmental Symptoms Questionnaire. | 0.21 scores on a scale | Standard Error 0.04 |
Secondary
Hypoxic Exercise Performance as Assessed by Time to Exhaustion at 80% of Hypoxic V̇O2max Reserve.
On day six of each supplementation protocol, participants completed a time to exhaustion test at 80% of their hypoxic V̇O2max reserve in acute hypoxia (FiO2 14.1%, equivalent 3225 m). Maximal exercise performance is defined as time to exhaustion (TTE) determined by the time from onset of test to task failure (volitional exhaustion or inability to maintain treadmill speed).
Time frame: Measured on the sixth day of supplementation
Population: Five participants did not complete the TTE on day 6 because of injury or technical reasons, e.g., cramp or tripping while on the treadmill, and one of these was also removed from analyses relating to RPE on day 5 because of failure to use the RPE scale consistently.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Nitrate | Hypoxic Exercise Performance as Assessed by Time to Exhaustion at 80% of Hypoxic V̇O2max Reserve. | 666 seconds | Standard Deviation 206 |
| Placebo | Hypoxic Exercise Performance as Assessed by Time to Exhaustion at 80% of Hypoxic V̇O2max Reserve. | 656 seconds | Standard Deviation 184 |