Condition category
Not Applicable
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status
No longer recruiting

Plain English Summary

Background and study aims
Many major international competitions for field hockey take place in hot environmental conditions (such as in the Rio 2016 Olympics). There is therefore a need to better understand how the body copes with the heat stress associated with high-intensity intermittent (stop-start) exercise and how this impacts upon field-hockey players’ physical performance and cognitive function (mental processing). Field hockey not only involves intermittent high speed running and sprinting but decision-making skills. Therefore it is important to understand how field-hockey specific exercise in hot conditions effects cognitive function. In addition, previous research from our lab has demonstrated that field hockey player compete when dehydrated, particularly during tournaments. The aim of this study is to determine whether cognitive function is impaired in hot and moderate conditions and when dehydrated following hockey specific exercise.

Who can participate?
Female elite field hockey players aged 18-40.

What does the study involve?
Participants complete four field hockey simulations in a random order, a minimum of 1 week apart, on a treadmill. Before and after each of the hockey match simulations cognitive function is assessed using laptop based software. The four simulations involve exercise in the heat in a normal hydration state; exercise in the heat when dehydrated; exercise in moderate conditions in a normal hydration state; and exercise in moderate conditions in a dehydrated state. Participants are familiarised with all the techniques and measurements during preliminary laboratory visits. For each simulation, participants have their cognitive function measured before and after each exercise test. In addition, their rectal temperature, how much they felt they are pushing themselves and thirst are measured every 10 minute during exercise.

What are the possible benefits and risks of participating?
Participants benefit from being provided with information about their current fitness levels and a training programme provided should they wish. In addition, information can be provided regarding a participant’s responses to exercising in hot conditions. Intermittent exercise in the heat is physically very demanding, and places strain on the body. Therefore, there is a risk that participants may feel faint or nauseas and/or suffer from heat stroke. All participants will be closely monitored in order to avoid this.

Where is the study run from?
Nottingham Trent University (UK)

When is the study starting and how long is it expected to run?
September 2006 to September 2008

Who is funding the study?
Nottingham Trent University (UK)

Who is the main contact?
Dr Caroline Sunderland

Trial website

Contact information



Primary contact

Dr Caroline Sunderland


Contact details

Erasmus Darwin Building
Nottingham Trent University
Clifton Lane
NG11 8NS
United Kingdom
+44 115 8486379

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

Effects of heat stress and dehydration on cognitive function in elite female field hockey players


Study hypothesis

Cognitive function would be impaired when hypohydrated and under heat stress.

Ethics approval

Nottingham Trent University School of Science and Technology Human Ethics Committee, 14/11/2006, ref: xxxviii

Study design

Single-centre randomised cross over trial

Primary study design


Secondary study design

Randomised cross over trial

Trial setting


Trial type


Patient information sheet

No participant information sheet available


Sports performance


Participants are randomised to undertake four exercise conditions in a random order. The exercise undertaken consists of 50 minutes of activity, divided into 2 x 25 min blocks of exercise separated by a 10 min intermission designed to replicate half time. This is performed on a motorised treadmill (h/p/cosmos Pulsar 4.0, Nussdorf-Traunstein, Germany) housed in an environmental chamber (WIR52-20HS, Design Environmental Ltd., Gwent, Wales, U.K) and consisted of different exercise intensities observed in match-play. Participants are required to hold a hockey stick for the entire duration of the protocol. The treadmill gradient was set at 1% to reflect the energy cost of outdoor running.

Condition 1: Participants complete exercise in heat (33.3 ± 0.1oC, 59 ± 1% rh) in a dehydrated state (achieved through undergoing a period in an chamber (~ 40oC, 75% rh))
Condition 2: Participants complete exercise in heat (33.3 ± 0.1oC, 59 ± 1% rh) in a hydrated state (ingestion of water ad libitum, in a thermally neutral environment (~ 19oC) for ~ 2 hours)
Condition 3: Participants complete exercise in a thermally neutral environment (~ 19oC) in a dehydrated state
Condition 4: Participants complete exercise in a thermally neutral environment (~ 19oC) in a hydrated state

All participants are monitored closely throughout the recovery period on completion of the main trials. Participants are fed, rehydrated and only permitted to leave the laboratory once they were euhydrated, core temperature had returned to normal levels and the participants confirmed they were feeling ‘normal’.

Participants undergo computerised cognitive function assessments at baseline and 60- minutes post-exercise in all four trial conditions. Additionally, rectal temperature, perceived exertion (self-reported) and perceived thirst (self-reported) are measured at baseline and every 10 minutes throughout exercise in each condition.

Intervention type



Drug names

Primary outcome measures

Cognitive function is assessed using the Stroop test, visual search (VS) test and Sternberg Working memory test before and 60 minutes after each exercise condition.

Secondary outcome measures

1. Rectal temperature recorded at baseline (time point 0) and every 10 minutes throughout exercise and immediately after completion of the final cognitive test battery in each exercise condition
2. Rating of perceived exertion on a scale of 6-20 using the Borg scale recorded at time point 0 and every 10 minutes throughout exercise in each exercise condition
3. Rating of perceived thirst (9 point scale ranging from not thirsty to very, very thirst) at time point 0 and every 10 minutes throughout exercise in each exercise condition

Overall trial start date


Overall trial end date


Reason abandoned


Participant inclusion criteria

1. 18-40 years old
2. Female elite
3. Elite field hockey players

Participant type

Healthy volunteer

Age group




Target number of participants


Participant exclusion criteria

1. Exercise-induced asthmatics
2. History of heart problems
3. Family history of sudden death below the age of 50

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

Nottingham Trent University
Department of Sports Science Clifton Campus
NG11 8NS
United Kingdom

Sponsor information


Nottingham Trent University

Sponsor details

Erasmus Darwin Building
Clifton Lane
NG11 8NS
United Kingdom
+44 115 9418418

Sponsor type




Funder type


Funder name

Nottingham Trent University

Alternative name(s)


Funding Body Type

private sector organisation

Funding Body Subtype



United Kingdom

Results and Publications

Publication and dissemination plan

Planned publication in a peer-reviewed journal.

Intention to publish date


Participant level data

Available on request

Results - basic reporting

Publication summary

Publication citations

Additional files

Editorial Notes