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Trial registered on ANZCTR


Registration number
ACTRN12617000425392p
Ethics application status
Submitted, not yet approved
Date submitted
20/03/2017
Date registered
24/03/2017
Date last updated
24/03/2017
Type of registration
Prospectively registered

Titles & IDs
Public title
Can N-acetylcysteine (NAC) supplementation enhance exposure to altitude in well-trained cyclists?
Scientific title
Can N­-acetylcysteine (NAC) supplementation enhance the haematological response and reduce excessive exercise ­induced fatigue in well trained cyclists during exposure to moderate altitudes?
Secondary ID [1] 291478 0
None
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Exercise performance 302536 0
Exercise induced inflammation 302537 0
Altitude induced illness 302539 0
Condition category
Condition code
Other 302080 302080 0 0
Research that is not of generic health relevance and not applicable to specific health categories listed above

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Supplementation with N-acetylcysteine (NAC) in a randomised, double-blind, placebo controlled study to assess the effects of supplementation on erythropoiesis, exercise-induced inflammation and performance during altitude training in athletes.

N-acetylcysteine (NAC) will be administered orally in tablet form, 1200 mg per day, daily for 2 weeks.

Supplementation will occur for a 6 day loading period prior to the first of 3 experimental trials, and for the duration of the exercise trials (1 week).

Double blind randomised placebo­ controlled crossover design. Well­ trained cyclists (n=12) will receive either NAC (1200mg/d) or a placebo supplement. Participants will complete 3, 2 h trials in each condition. Trials will be conducted in a hypoxic chamber located at the NSW Institute of Sport and administered/supervised by one of the researchers (exercise physiologist). On the days of the exercise trials, the daily dose of NAC/placebo will be taken 2 hours prior.
­ Control, seated in normoxia
­ Hypoxia, seated in fraction of inspired oxygen [FiO2]=15%
­ Exercise + hypoxia, FiO2=15%, 30 min seated, incremental cycle test to exhaustion (starting at a power output of 2 Watts per kg body mass, increase 50 watts every 3 minutes until exhaustion), 20 minutes recovery, repeat sprint protocol (3 sets of 12 x 5 s efforts with 30 s rest - interspersed with 5 min recovery)
Venous blood samples (pre, post and 2 h post) will be taken to assess hypoxic ­inducible factor 1­alpha, nuclear factor ­kappa B, EPO, gluthathione:reduced glutathione ratio (GSSG:GSH) and a full blood count. At least 36 h between each trial and a 3 wk washout between conditions.
Intervention code [1] 297541 0
Treatment: Drugs
Comparator / control treatment
Placebo (sucrose), oral administration in tablet form, identical in size and appearance to NAC treatment
Control group
Placebo

Outcomes
Primary outcome [1] 301511 0
Changes in markers of erythropoiesis (Hypoxic - inducible factor 1alpha, EPO) will be assessed through venous blood samples at various timepoints.
Timepoint [1] 301511 0
Venous samples will be drawn pre, post and 2 hours post each trial, as well as 1 week following the final trial.
Primary outcome [2] 301512 0
Changes in cycling performance (incremental exercise and repeat sprint)
Assessed by exercise task in hypoxia with either NAC/placebo supplementation
Cycling performance will be measured by maximal power output, and trials will be completed on a cycle ergometer (Schoberer Rad MeQtechnik SRM GmbH)
Timepoint [2] 301512 0
The exercise trial will be timed on either day 1, 4 or 7 (randomised order of trials) following a 6 day loading period with NAC/placebo.
Primary outcome [3] 301553 0
Changes in markers of oxidative stress (GSH:GSSG ratio) will be assessed through venous blood samples at various timepoints.
Timepoint [3] 301553 0
Venous samples will be drawn pre, post and 2 hours post each trial, as well as 1 week following the final trial.
Secondary outcome [1] 332885 0
Changes in markers of cellular adaptation to endurance training (nuclear factor kappa B) will be assessed through venous blood samples at various timepoints.
Primary outcome
Timepoint [1] 332885 0
Venous samples will be drawn pre, post and 2 hours post each trial, as well as 1 week following the final trial.
Secondary outcome [2] 333016 0
Athlete training status
Customised training questionnaire utilising the session rating of perceived exertion (RPE) method of training quantification. Briefly, for each training session, participants provide the duration in minutes, distance completed in kilometres (blank if strength training/cross training) and an RPE score (0-10) with 0 being no exertion and 10 being maximal exertion. Session load is calculated by multiplying duration and RPE. As per Foster et al., 2001, A new approach to monitoring exercise training, Journal of Strength and Conditioning Research, 15, 109-115
Timepoint [2] 333016 0
Daily during study period (from commencement of 6 day loading period until 1 week post final exercise trial). Repeated with crossover supplement
Secondary outcome [3] 333017 0
Athlete health and wellbeing
Customised health and wellness questionnaire
Briefly, participants are asked to rate on a 1-10 Likert scale (1 not at all/poor/minimal, 10 extremely/excellent) perceptions of sleep quality, body soreness, fatigue, general health, mood, mental readiness to train, physical readiness to train. Additionally, participants will be ask yes/no whether they are sick, and if yes, to list any symptoms e.g. headache, upper respiratory, congestion etc.
Timepoint [3] 333017 0
Daily during study period (from commencement of 6 day loading period until 1 week post final exercise trial). Repeated with crossover supplement

Eligibility
Key inclusion criteria
For inclusion in the investigation, participants must fulfil the below criteria:
Sex: Male and female
Age range: 18 to 40 y
Disease status: Healthy individuals
Well trained cyclists with a high level of physical fitness (VO2max above 55 ml/kg/min)
Completed 10-­15 hrs of training per week for at least 2 years
Willingness to give written and oral informed consent.
Willingness to participate to and comply with the study.
Minimum age
18 Years
Maximum age
40 Years
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Participants will be excluded from participation based on the below criteria:
Regular NAC supplementation use for the previous 6 months
Illness or injury which may be exacerbated through participation in the study
Exposure to a hypoxic stimulus in the previous 3 months
Inconsistent pre­testing diet and exercise
Women lactating, pregnant or of childbearing potential who are not willing to avoid becoming pregnant during the study.
Patients with a history of a psychological illness or condition such as to interfere with the patient's ability to understand the requirements of the study.
Patients with a haematological disease that is likely to interfere with the evaluation of the patient's safety and of the study outcome.
The following medication(s) can have interactive effects, may confound the findings of the investigation and may interfere with the patient's ability to meet the study requirements; they cannot be administered during the clinical study:
Any antioxidant vitamins and mineral supplement
Any substance or method included in the World Anti-Doping Association List of Prohibited Substances and Methods. Unless the participant has a Therapeutic USE Exemption for the substance /method from the Australian Sports Anti-Doping Authority

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Central randomisation via computer
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Order of crossover will be generated using simple randomisation using a randomisation table created by computer software (i.e. computerised sequence generation)
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s
The people administering the treatment/s
The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Crossover
Other design features
randomised crossover trial
Phase
Phase 4
Type of endpoint/s
Efficacy
Statistical methods / analysis
Sample size calculation: Participant numbers were selected in line with subject numbers in previous similar supplementation and altitude training studies. This subject number is sufficient to determine significant differences in performance and biochemical parameters with a statistical power of 80%, an alpha level of 0.05 and an estimated effects size of 1.0 SD units.
Analysis plan: Repeated measures ANOVA with three way analysis – condition (NAC or placebo) x time (pre, post, 2 hours post) x order of crossover.


Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
1/04/2017
Actual
Date of last participant enrolment
Anticipated
31/07/2017
Actual
Date of last data collection
Anticipated
31/10/2017
Actual
Sample size
Target
12
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
ACT,NSW,QLD,TAS,VIC

Funding & Sponsors
Funding source category [1] 295949 0
Government body
Name [1] 295949 0
Australian Institute of Sport
Country [1] 295949 0
Australia
Funding source category [2] 295952 0
Government body
Name [2] 295952 0
NSW Institute of Sport
Country [2] 295952 0
Australia
Funding source category [3] 295953 0
University
Name [3] 295953 0
University Technology Sydney
Country [3] 295953 0
Australia
Funding source category [4] 295954 0
University
Name [4] 295954 0
Australian Catholic University
Country [4] 295954 0
Australia
Primary sponsor type
Government body
Name
Australian Institute of Sport
Address
Leverrier St, Bruce ACT 2617
Country
Australia
Secondary sponsor category [1] 294840 0
Government body
Name [1] 294840 0
NSW Institute of Sport
Address [1] 294840 0
1/6 Figtree Dr, Sydney Olympic Park NSW 2127
Country [1] 294840 0
Australia

Ethics approval
Ethics application status
Submitted, not yet approved
Ethics committee name [1] 297225 0
UTS Human Research Ethics Committee
Ethics committee address [1] 297225 0
15 Broadway, Ultimo NSW 2007
Ethics committee country [1] 297225 0
Australia
Date submitted for ethics approval [1] 297225 0
22/02/2017
Approval date [1] 297225 0
Ethics approval number [1] 297225 0

Summary
Brief summary
Athletes regularly incorporate living and training at altitude into their programs to enhance physiological and performance adaptations. It can be logistically difficult and expensive for Australian athletes to gain the benefits of altitude training. Current options available in Australia are limited to relatively low levels of natural altitude or the use of artificial hypoxic environments. Preliminary data suggests that supplementation with the antioxidant n­acetylcysteine (NAC) may boost the erythropoeitic response (i.e. increase red blood cell production) to hypoxia and support the immune system during strenuous training blocks. However, to date, the efficacy of NAC to enhance these physiologic systems has not been determined in an applied sports setting.
This investigation forms part of a series of studies will be the first to comprehensively examine the acute effects of NAC supplementation to augment the physiological adaptations to hypoxic exposure in elite athletes. It will also contribute to the existing knowledge regarding the ergogenic effect of NAC on repeat sprint cycle performance in well trained cyclists and add further real-­world data to the debate regarding the potential blunting of cellular adaptations with antioxidant supplementation. Importantly, it will also provide valuable information to physiologists, coaches and athletes regarding the prescription and periodisation of NAC supplementation and the optimal integration of hypoxic interventions to produce peak performance during targeted competitions.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 73390 0
Dr Katie M Slattery
Address 73390 0
UTS Sport and Exercise Science, Moore Park precinct, PO Box 123 Broadway NSW 2007
Country 73390 0
Australia
Phone 73390 0
+61 412 352 843
Fax 73390 0
Email 73390 0
katie.slattery@uts.edu.au
Contact person for public queries
Name 73391 0
Mr Avish P Sharma
Address 73391 0
Physiology, Australian Institute of Sport, Leverrier Cres Bruce, ACT, 2617
Country 73391 0
Australia
Phone 73391 0
+61 432 975 939
Fax 73391 0
Email 73391 0
avish.sharma@ausport.gov.au
Contact person for scientific queries
Name 73392 0
Dr Katie M Slattery
Address 73392 0
UTS Sport and Exercise Science, Moore Park precinct, PO Box 123 Broadway NSW 2007
Country 73392 0
Australia
Phone 73392 0
+61 412 352 843
Fax 73392 0
Email 73392 0
katie.slattery@uts.edu.au

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Results publications and other study-related documents

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