By Ann Gates

(@exerciseworks)

Giving regular exercise advice and support as part of every health care consultation is fast becoming a critical health intervention in the prevention of the ‘tsunami’ of lifestyle diseases such as obesity, diabetes and related cancers. In May 2012 the U.S. Centre for Disease Control together with the Institute of Medicine released a national report detailing recommendations to combat the ‘Weight of the Nation’. The data predicted 42 percent (or 32 million more people) of the American population would be obese by 2030, while 11 percent would be severely obese. The economic costs for the associated health care services: $550 billion. This is an unsustainable cost for most health care systems and countries. This burden of lifestyle diseases and suffering is an unacceptable outcome for 21^st  century medicine.

The ‘Weight of the Nation 2012’ report summarised the key actions as:

1. Integrating physical activity into people’s daily lives
2. Making healthy food and beverage options available everywhere
3. Transforming marketing and messages about nutrition and physical activity
4. Making schools a gateway to healthy weights
5. Galvanizing employers and health care professionals to support healthy lifestyles

Several ‘best practice’ initiatives covering both healthier diets and integrating physical activity are identified. The authors report that physical activity should be a ‘routine and integral part of daily life’.

This provides the ‘call to action’  for health professionals to lead on giving exercise advice and support to patients, relatives and caregivers on why regular exercise helps prevent and treat many lifestyle diseases or ‘non communicable diseases’ (#NCDs). 36 million people, around the world, die from lifestyle diseases each year. They are names and faces in every doctor’s waiting room, every hospital outpatient clinic and everybody’s family. This is a global health issue that needs urgent health professional intervention by every health professional around the world.

Giving physical activity advice to everyone is not as easy as it seems. We know that when doctors give exercise advice to patients that they are more likely to follow that advice (read more here).  We also know that brief intervention during doctor –patient consultations is cost effective.

Exercise advice to patients should include warm up, exercise plan and cool down instructions on how to exercise effectively and safely. A weekly, balanced exercise programme for patients with chronic diseases should include cardiovascular, strength, flexibility and balance exercises. Different diseases often respond better to different types of exercises and physical activities. For example, Nordic walking or ballet has been shown to help improve the symptoms of patients with Parkinson’s disease.

Patients deserve the choice to choose how to incorporate ‘exercise as a medicine’ into their daily lives and in the prevention and management of long term diseases. Health care professionals can use tools like the American Cancer Society’s ‘Make Time-Break Time’ infographic to help patients understand the risks of inactivity and sedentary behaviour to their health during the day. This helps patients to ‘choose’ to increase their activity levels as part of the clinical management of their health condition.

The more health professionals consult with their patients on the benefits of regular exercise and more patients start to realise the benefits to their health, the more likely health care organisations around the world can start to address the obesity and non communicable diseases epidemic in a sustainable way.

This is a call to action to change our clinical practice and implement the concept of exercise as a medicine in the prevention and treatment of chronic diseases. Exercise advice and support should be part of EVERY consultation.

It is also time for sports and exercise professionals, health care professionals and patients to work together to help improve both the weight and health of nations all around the world.

Follow this link to see ‘part 1′ of this blog. It has 292 tweets to date – a BJSM record! Thanks everyone for promoting physical activity.

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Ann Gates BPharm(Hons)  MRPharmS

Personal Trainer, Chronic Disease Exercise Specialist, BACPR Exercise Instructor.

Founder of Exercise Works!

www.exercise-works.org

@exerciseworks

email: ann@exercise-works.org

Sport and Exercise Medicine: The UK trainee perspective (A monthly series on the BJSM blog)

By Dr. Andrew Murray

Increasing Physical Activity is the biggest public health challenge of the 21st century.  Steven Blair’s message is so powerful that it is worth taking to the ends of the earth. I’m currently working for our CMO Harry Burns in the Scottish Government, promoting physical activity for health as part of their Sport and Physical Activity policy team.  Sir Harry is a fantastic advocate for this important form of medicine and enjoys running himself.

In March I received a late call up to take part in the North Pole Marathon. The race itself takes place at the Geographical Pole.  I’d be helping provide medical cover whilst competitors readied themselves and went husky racing etc. in Spitsbergen – 79 degrees North.  The North Pole is only “inhabited” for 3 weeks of the year, as for the rest of the year it is either permanently dark or the ice starts to break up.  Russians sky-dive in and set up an ice runway each year.  The video footage of tractors floating down on parachutes over the pole is bizarre.  The base doctors take care of competitors during the race itself, with a full medical kit that included a gun. Race director Richard Donovan explained that if a polar bear did turn up that it would be disqualified for failure to enter the race and could be discouraged from hanging around by firing a few shots in the air.

The old medical idiom that “prevention is better than cure” holds true in the Arctic, and of frostbite and hypothermia in particular. We advised competitors on clothing strategy (basically to cover every inch of the body), and when to seek medical attention. The risk assessment ensured that a lapped course kept competitors visible to staff, and avoided any leads/breaks in the ice. A warm tent was available to stock food and water for runners and to ward off any impending hypothermia.  Warm areas had been assigned for self-treat i.e. blisters, as well as for minors and majors.

The race itself is like no other, run not on land but on the frozen Arctic Ocean. Some competitors wear snowshoes with their Gore-Tex trainers to traverse the white world of this beautiful natural freezer.  The 9th of April brought perfect conditions of -26 Celsius and light winds.  The full medical kits were cross checked and the race began.

Amazingly all 41 competitors, from 18 different countries finished with the event even featuring a marriage proposal. Spectator numbers were low, although a seal did pop up occasionally.  I ran round in 4hrs 17 mins, whilst the final competitor took over 11 hours.  There were only a few relatively minor cases of frostbite (much to the disappointment of the documentary makers), in addition to the common expected musculoskeletal injuries.  Anterior knee pain was especially common probably due to the wide gait adopted to chew through the deep snow by most runners, whilst other injuries seen included Achilles tendinopathy, ankle dorsiflexor tendinopathy, and a hip flexor injury. I helped patch runners up once I had finished, and advised the few that were injured on appropriate treatment, including what to tell their doctor in Mauritius who presumably doesn’t see much frostbite.

I think we all have the opportunity to promote physical activity for health.  Steven Blair, Karim Khan, Mike Evans, Richard Weiler and others have done much to produce data, and frame it imaginatively. 23 and a half hours is a must share resource, and sticky messages like “Smokadiabesity” seem to resonate with the public and policy makers.   Additionally, sporting events like the North Pole Marathon offer the chance to put forward a health message.

On a personal level, I’m looking forward to running seven ultra-marathons on seven continents in seven days in November this year, with the sole aim of promoting physical activity as the single best thing that we can do for our health.

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Follow Andrew on twitter at @docandrewmurray

Andrew Murray is a Sport and Exercise Medicine Registrar in Scotland.  His book is called “Running Beyond Limits” Mountain Media.  He failed to mention in his blog that he won the North Pole Marathon 2012!

Dr James Thing co-ordinates “Sport and Exercise Medicine: The UK trainee perspective” monthly blog series.

Professor Jon Drezner emphasises the need for careful planning and practice of emergency protocols in the sports medicine setting. He also shares the new criteria for ECG screening – these lead to a much lower false positive rate than was previously reported. He makes a compelling case to include a resting 12-lead ECG in the periodic health examination of athletes

Click here for link to podcast page

By  Francois Trudeau and Roy J. Shephard

Soccer has recently been commended as a means of enhancing health in adults with cardiac risk factors [1, 2]. However, a re-reading of the “Book of Fate” [3] suggests that this approach was not exactly news to the French satirical author Voltaire (1694-1778). In this story, Zadig is a Babylonian philosopher who, in his travels, stumbles upon a group of women who are seeking a basilisk, a rare and legendary beast that is king of the serpents. The local physician has suggested this animal can cure Ogul, their Lord and Master. Zadig offers Ogul an alternative remedy, in return for the freedom of the beautiful Astarte:

“Zadig, again addressing himself to Ogul, said; my Basilisk, Sir… is not to be drest or eaten; but all its Virtues must penetrate your whole Fabrick, thro’ your Pores; I have inclos’d my never-failing Sudorific in a Bladder, full-blown and carefully cover’d with the softest Leather. You must kick this Bladder, Sir, once a Day about your Hall for a whole Hour together, with all the Vigour and Activity you possibly can. This Medicine must be repeated every Morning…., Upon your due Observance of the Regimen I shall put you under, I doubt not, but with the Blessing of Heav’n on my honest Endeavours, I shall give you ample Demonstration of my being an Adept in Physick. Ogul, upon making the first Experiment, was ready to expire for want of Breath, and thought he should die with the Fatigue. The second Day did not prove altogether so irksome, and he slept much better at Night than he had done before. In short, our Doctor in about eight Days Time, perform’d an absolute Cure. His Patient was as brisk, active and gay, as One in the Bloom of his Youth.

Now, Sir, said Zadig, I’ll…. disclose to you the important Secret. You have play’d at Foot-ball these eight Days successively; and you have liv’d all that Time, within the Bounds of Sobriety and Moderation. Know, Sir, that there is no such Animal in Nature as a Basilisk; that Health is to be secur’d by Temperance and Exercise…

Ogul’s physician was very reluctant to let such an “anti-medicinale” cure eclipse his own reputation. He plotted with “a set of petty doctors and apothecaries” to poison Zadig, but the latter avoided his planned death with a “rendez-vous gallant.”

Voltaire is known for a less than stellar opinion of the Enlightenment physician, described as one who [4]:

«pours drugs of which he knows little into a body of which he knows less.”

However, Voltaire himself seems to have grasped the health value of 60 minutes of vigorous physical activity per day.

REFERENCES

1. Krustrup P, Aagaard P, Nybo L et al.  Recreational football as a health promoting activity: a topical review. Scand J Med Sci Sports. 2010; 20 Suppl 1:1-13.

2. Randers MB, Petersen J, Andersen LJ et al.  Short-term street soccer improves fitness and cardiovascular health status of homeless men. Eur J Appl Physiol. 2011; Sep 29. [Epub ahead of print]

3. de Voltaire, F-MA. Zadig, ou la destinée (Zadig, or the Book of Fate, an Oriental history). 1747/2008, Chapter XV, The Basilisk. (English translation). Boston, Mass : MobileReference.

4. Editor. Medicine a science. Eclectic  Medical Journal (Ohio State Medical Association, Worthington, Ohio) 1871; 31 : 140-141.

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Prof Francois Trudeau – Department of Physical Activity Sciences, Université du Québec à Trois-Rivières Trois-Rivières , P.Q., Canada.

 Prof Roy J. Shephard - Faculty of Kinesiology & Physical Education, University of Toronto, Toronto, ON.

VOTE HERE (CLICK) NOW! (until May 15th)

The first semi-final of the cover competition was tight! The winner advanced to the final with a one vote margin!  Still a secret though! Now we have the 2nd semi-final.

Rules refresher!

1. Semi Final 2 goes until midnight Oslo time: May 15th 2012.

2. You can vote in each round [more chances to win the prize!]. Takes you 20 seconds to vote and win!

3. Each Semi Finals include 3 covers each.

4.Next week is the Grand Final / World Cup / Superbowl!…. where readers choose the BJSM cover of the year (2011) from the Semi winners!

4. Voters (from all rounds) will be entered into a draw for PRIZE of $133 gift certificate to amazon.com. We need your email to know if you won – we delete them all after the competition.

VOTE HERE (CLICK) NOW! (until May 15th)

Thought you might be interested in seeing our latest edition to the Every Body Walk campaign.  This PSA features the cast from The West Wing TV show.

We are releasing this virally, and its had over 300,000 hits in 3 days.

http://www.funnyordie.com/videos/3dc51a407a/walk-talk
Behind-the-scenes
http://www.youtube.com/watch?v=MCZQqu2Xlms

See also Bob Sallis’ compelling case for doctors including exercise as the 5th vital sign – every consultation. This has had over 4,000 views.

And in the Steve Blair-edited Special Exercise is Medicine theme issue (Jan 2009), Bob included an argument for the doctor’s role in prescribing - share this with your colleagues!

Finally – for those who haven’t seen Mike Evans’ viral video ’23.5 hours’ - it fits beautifully with ‘Everybody Walk’. Click on this link to the BJSM blog and watch it for 9 minutes! It has had nearly 3 million views!

The Canadian Paediatric Society has called for legislation mandating helmet use for all skiers and snowboarders. The Society says that through mandatory helmet legislation, governments can send a strong message that helmets are important and reduce the risk of brain injury and disability.

For the record, I am a strong advocate for helmets for skiers and snowboarders and have been so for years. I just do not support, with all its attendant issues and challenges, mandating their use. Public education and public awareness is more effective, cheaper, no public/user push-back, etc, etc. And with no taxpayer-funded inspectors roaming these facilities armed with citation books and empowered to hand out fines and other penalties.

Terrible tragedies, including the skiing death of actress Natasha Richardson at Quebec’s Mont Tremblant in 2009, always spark discussion and debate about wearing a helmet when skiing or snowboarding. Should skiers and snowboarders wear helmets?  Without question, the answer is yes!  Helmets are proven critical life-saving and injury -prevention equipment. A Norwegian study published in February 2006 in the Journal of the American Medical Association found that using a helmet was associated with a 60 percent reduction in the risk of head injury. Blows to the head are among the most devastating and lethal types of injury. Although head injuries are quite rare, an estimated 60 percent of skiing fatalities involve a head injury. Even if it is not fatal, such an injury can have lifelong consequences.

Some experts do question whether helmet use also prevent the most serious types of head injuries while skiing and snowboarding. Dr. Jasper Shealy, an American researcher who is recognized as an expert on the subject, supports helmet use but points out the rate of skiing fatalities has not dropped despite much greater helmet use on the slopes. In other words, helmets just cannot prevent catstrophic injuries in some ski hill accidents.

While children are most likely to wear a helmet, the recent surge in helmet use on Canadian hills, according to the Canada Safety Council, is reflected in all age groups. Today’s helmets are so light and stylish that many skiers consider them not only effective safety equipment but also as a fashion accessory. According to the Canadian Ski Council, helmet use has risen dramatically over the last few years for skiers and snowboarders. Nova Scotia, which recently passed legislation mandating helmet use,  already had one of the highest rates of helmet use on ski hills in Canada at 88 %.

The Canada Safety Council does not favour mandatory helmet use, which brings into question enforcement and its related challenges. Public education, public awareness, commonsense, adults and parents teaching by example, and working with operators to further educate skiers and snowboarders  are the way to go to get that many more skiers and snowboarders to wear helmets on the slopes.

Emile Therien,
Public Health and Safety Advocate,
Past President, Canada Safety Council,
326 Frost Avenue,
Ottawa. ON.
Tel:613-737-4965.

Related BJSM articles

Sports helmets now and in the future. 2011. Andrew Stuart McIntosh, Thor Einar Andersen, and Roald Bahr et al. 

The effectiveness of helmet wear in skiers and snowboarders: a systematic review. 2010. Michael D Cusimano, Judith Kwok.

Related BJSM Blogs

Injury prevention in high level snowboard: A need to return to first principles?

Is high level snowboard too dangerous to allow your children to participate?

Concussion: how do we reconcile risk-averse policies with risk-taking sports

We join the world in mourning Sarah Burke

Concussion Position Statement: Why it’s not a KO.

By Helen Millson (M.Phil.Sports Physio UCT)

Well-known FIFA sports physio Mario Bizzini called groin pain “The Bermuda Triangle of Sports Medicine?” (1) with good reason! There is little consensus on groin pain management. The key is the Correct Diagnosis – Easier said than done! This blog introduces key issues for more junior sports clinicians.

What is Groin Pain?

Undergraduate training often fails to emphasise the two joints in the pelvis –   the hip joint and also the pubic symphysis are at the centre of many movements. (2)  As a clinician, try to assess how the patient’s functional movement influences both the hip and the pubic symphysis. What causes pain and where?  Try to understand the entire kinetic chain with its related function to the pelvis / groin / hip. Then perform relevant clinical tests as well as sports-specific functional tests.

The cause of groin pain is a ‘million dollar question’…….

The diagnosis is mostly by exclusion not inclusion. Osteitis Pubis (OP) diagnosis is no longer an accepted term. This may be a normal response to overload and may lead to bone stress reaction, and then possibly joint and disc degeneration. Increased signal of bone marrow oedema may be a precursor to the development of groin pain. It may or may not correlate with clinical symptoms. (3) As a clinician, consider prevention and reducing load when there are early groin pain symptoms or radiological changes (MRI) of excess load.

And what of the Adductor muscles? (4)

In soccer players with groin pathology, adductor dysfunction is a more frequent MRI finding than “osteitis pubis”. Both entities are mechanically related and frequently coexist.

Specific strengthening of all Adductor muscles is one of the main goals for preventing and managing groin / hip pathologies.

However, one must not be single minded and should take into account other structures including Ligamentum Teres tears (5), Ilio Psoas (6), Greater Trochanter (7), Rectus Abdominus (8), Pelvic floor muscles (9) and Gluteus muscle function (10).

Then consider Radiologists with their preferred way of imaging.

Although radiological investigations are important, most studies tend to agree that experienced clinical judgment remains a critical element in the diagnostic pathway. (11)

A few groin / hip tests have been well documented and are valuable for diagnosis. (12)

What about the treatment options?

There is consensus in the literature that non- surgical treatment should always be applied before surgery is considered. However, the time span differs in the studies.

The rehabilitation protocols show gradual progression based on objective functional and clinical markers over a reasonable time frame.

In my experience, it is of value to always have pre-season specific baseline tests (Musculo-Skeletal evaluation).

The rehabilitation can take anything from 3 – 12 weeks depending on the actual diagnosis e.g. if it is an overload problem, one would “actively rest” the athlete until they are able to fully function symptom free in their respective sport.

One should address the local strength first, followed by functional strength with the entire global perspective taken into account.

Reassessment criteria to judge progress and assess next level of activity with objective markers are essential in order to increase the rehabilitation appropriately.

Of course, at an elite sports level, one is mostly not given this time-frame to do conservative rehabilitation!

Post-operative rehabilitation programmes varies from 10 days – 12 weeks.

This depends on the type of surgery, the specific demands  and………the very different requirements of the Surgeon involved!

And surgery:

•   No consensus as to an ideal operating technique

•   Serial patient outcome measurements are needed to base intervention success on factors other than return to sports activity.

• Operate on asymptomatic side, as it has been suggested that 40% progress to bilateral?

There is also on-going controversy regarding the prevalence of a True Hernia, with many different surgical implications. (13)

Then on to the discussion regarding hips…….

The prevalence of radiographic hip abnormalities in elite soccer players is considerable. (15)

One must identify the relationship between these radiographic abnormalities and the clinically symptomatic pathologies.

A battery of tests should be utilised to improve the accuracy of the clinical reasoning.

Hip joint restriction often precedes the development of chronic groin injury and may be a risk factor for this condition.

One must also remember that the Acetabular Labrum and Ilio-Femoral Ligament are vital for normal hip mechanics and excessive removal of either in surgery can be detrimental.  (16)

As our understanding of FAI and chondral injuries and their causes grows, future efforts will focus on prevention.

Future research is required to determine the extent to which physio intervention aimed at improving hip kinematics would be effective in treating individuals with labral injuries

CONCLUSION

•   The challenge lies between ascertaining the Anatomical diagnosis vs. Pathological diagnosis vs. Functional diagnosis – the interaction of the three will influence prognosis and management, whereas identification of one alone will give a bias in one direction.

SOLUTION?

•     In spite of minimal EBM, it seems the most pertinent point is that many of the groin /hip pathologies can be averted by thorough and specific pre-habilitation, bearing in mind the entire kinetic chain and addressing total function around the pelvis above and below.

References

1)    Bizzini M. “Warm: Up the Bermuda Triangle of Sports Medicine?” in BJSM 2011.

2) William Meyer, FA Conference London Dec 2011

3)  Paajanen H. 2009. “Sports hernia” and osteitis pubis in an athlete. Duodecim. 125(3):261-6.

4)  Wiktorsson-Möller, Oberg , Ekstrand , Gillquist,1983. AJSM; Lynch SA, Renström PA.1999. Sports Med; Orchard et al., 2005. Clin J Sport Med; Cunningham et al. 2007; Phillipon 2009; Lloyd 2009; Thorborg 200; Crow 2010; Gilmore 2011; Davis et al, 2011; Connell 2011; Schilders 2012 and many others.

5)  Botser IB, Martin DE, Stout CE, Domb BG. 2011. Tears of the ligamentum teres: prevalence in hip arthroscopy using 2 classification systems. Am J Sports Med. Jul;39 Suppl:117S-25S.

6)   Hölmich P. 2007. Long-standing groin pain in sportspeople falls into three primary patterns, a “clinical entity” approach: a prospective study of 207 patients. BJSM. Apr;41(4):247-52; discussion 252. Epub 2007 Jan 29.

7)  Steinbrueck A, Hocke S, Heimkes B. 2011.Apophyseolysis of the greater trochanter through excessive sports: a case report. Am J Sports Med. Jan;39(1):195-8.

8)  Connell D, Ali K, Javid M, Bell P, Batt M, Kemp S. 2006. Sonography and MRI of rectus abdominis muscle strain in elite tennis players. Roentgenol. AJR Am J. Dec;187(6):1457-61.

9)  Ruth C. Lovegrove Jones, Qiyu Peng, Maria Stokes, Victor F. Humphrey, Christopher Payne, Christos E. Constantinou. Mechanisms of pelvic floor muscle function and the effect on the urethra during a cough. Eur Urol 2010;57:1101-10.

10)  Graham RB, Costigan PA, Sadler EM, Stevenson JM. 2011. Local dynamic stability of the lifting kinematic chain. Gait Posture. Oct;34(4):561-3; Philippon MJ, Decker MJ, Giphart JE, et al.2011. Rehabilitation exercise progression for the gluteus medius muscle with consideration for iliopsoas tendinitis: an in vivo electromyography study. Am J Sports Med. Aug;39(8):1777-85. Epub 2011 May 12.

11) Garvey JF. 2011. Computed tomography scan diagnosis of occult groin hernia. Hernia. 2011 Dec 14.

12)  Delahunt  et al. Man Ther. 2011; Anthony Hogan, FA Conference London 2008; Pers Holmlich, BJSM 2004, BJSM 2007; Mallarias, Hogan et al BJSM 2009; James Moore Rehabilitation Chapter in Prof Haddad Book -  “The Young Adult Hip in Sport”. To be published 2012.

13)  Connell DG…. Patient care – crunch time. Br J Gen Pract. 2009

14) Gerhardt et al, AJSM 2011

15) Myers AJSM 2011

The CAS has ruled that the British Olympic Association cannot exclude dopers who have served their bans from future Olympic teams. The decision pushes Dwain Chambers back into the spotlight. He has kept a low profile over the past few months, although his agent, barrister Siza Agha, has been eloquent on his behalf:

“Redemption is an integral foundation… of any democratic society. It is not recognised in dictatorships, Greek mythology and the British Association bylaw.”

Well, the BOA bylaw has been deemed “noncompliant” with World Anti-Doping Agency rules. If Dwain Chambers runs the qualifying time and achieves a top-two finish in the 100m trials, he will be given a spot on the British team.

In the words of head coach Charles Van Commenee, Chambers is “a  likeable guy and a damned fine athlete.” His willingness to share his story has helped anti-doping efforts and dissuaded other athletes from making the same mistakes. A home Olympics swansong would represent an unexpected chance for redemption on the running track. Although probably still Britain’s fastest man at thirty-three, Chambers would be outside shot to reach the 100m final. It has been his misfortune to get caught in the crossfire of an overheated and complex debate.

The question of what sanctions to impose upon drugs cheats is understandably an emotive one, particularly for the clean athletes who spend years pushing their bodies to their natural limits. Sebastian Coe and Daley Thompson, two of the senior statesmen of British athletics, have been outspoken in their support for lifetime bans.

Such a stiff sanction would be difficult to enforce. If you want to impose a lifetime ban, which will destroy an athlete’s career, then the proof of their guilt needs to be pretty devastating. For a variety of reasons, doping control scientists are not yet able to establish such a secure verdict in most cases. More frequent and stringent testing would help, but we should be wary of sacrificing the right to privacy in the name of clean sport.

There is also a strong case for distinguishing between accidental and deliberate cheating, particularly in cases like LaShawn Merrit’s. The 2008 Olympic 400m champion tested positive for a banned steroid and was given a short ban, as the court was convinced that he took it inadvertently when he tried the male enhancement product Extenze.

WADA has done part of its job by bringing consistency to doping sanctions, it now needs to consider whether these sanctions are tough enough. The vast majority of athletes and fans want competition on a level playing field. I hope that’s what we see in London this summer.

For BJSM podcast with WADA head Alan Vernec and Deputy Editor Babette Pluim click here. (Follow @DocPluim)

See also leading Sports Ethics expert Mike McNamee’s 2011 comments on doping and sport here

And discussion of the challenges of doping test (for B-2 agonists) in asthma here

By  Drs. Zachary J. Schlader &  Toby Mündel 

In response to:  Barwood MJ, Corbett J, White D, et al. Early change in thermal perception is not a driver of anticipatory exercise pacing in the heat. Br J Sports Med 2011

Dear Editor,

We read with great interest the study by Barwood and colleagues published recently within BJSM  [1].  In this study, the authors aimed to explore the relationships between body temperature(s), thermal perception, and the voluntary control of exercise intensity in the heat.  For this they should be commended for although this area is quite topical, our understanding of these relationships remains virtually unknown.  By chemically activating peripheral cold thermo-sensors with menthol, Barwood et al. [1] have demonstrated that improvements in thermal comfort and reductions in sensations of warmth, independent of changes in skin temperature, both prior to, and during, the initial stages of self-paced exercise in the heat did not influence the selection of exercise intensity.  Although the conclusions drawn appear appropriate, we would like to further discuss their results in the context of others to explore this topic and perhaps allow a better understanding of our current base of knowledge.

As part of the rationale for conducting their study, Barwood et al. [1] state “It is presently unknown whether altered pacing strategy is regulated as part of behavioral thermoregulation driven by a conscious awareness of thermal state or if a central and subconscious homeostatic mechanism is activated when skin temperature rises above a threshold rate”. Furthermore, Barwood et al. [1] conclude that “This study addresses an as-yet unanswered question of whether the fatiguing mechanisms during exercise in the heat are primarily consciously or subconsciously mediated”.  Firstly, we would like to draw the authors’ attention to our recent work testing the hypothesis that voluntary reductions in exercise intensity in the heat are thermoregulatory behaviors [2].  Our results demonstrated that the observed reductions in power output during exercise in ~40°C compared to ~20°C were, at least in part, due to a conscious action that was inversely related to total heat body storage and thermal discomfort, and improved heat exchange [2].  Secondly, it is unfortunate that it was not possible to discuss two of our recent studies demonstrating that skin temperature and/or the perceptions of this temperature play a large role in the initial selection of [3] or sustained decrease in [4] exercise intensity.  Perhaps in “addressing [only] two current viewpoints on how exercise pacing is driven in hot conditions” Barwood et al. have unintentionally overlooked this recent evidence?

This notwithstanding, the results put forward by Barwood and colleagues [1] appear to be in stark contrast to those we obtained utilizing a similar methodology whereby menthol and skin cooling was used to independently alter thermal perception and skin temperature during exercise at a fixed rating of perceived exertion (RPE) [5]. These results showed that an improved thermal comfort and reduced sensations of warmth with menthol enhanced the capacity to maintain exercise intensity.  Thus, we concluded that thermal perception is a capable modulator of exercise intensity independent of any change in skin temperature [5]; so why, then, such opposing views?

As supported by Barwood et al. [1], it is becoming increasingly clear that RPE is perhaps the most dependable criterion dictating the voluntary selection of exercise intensity [6].  In such circumstances, it appears as though, independent of perturbation (e.g. hypoxia, heating, cooling etc.), the exerciser compares how they feel to how they expect themselves to feel at that moment in time and adjust their exercise intensity accordingly [6].  Thus, although the RPE response during self-paced exercise appears to be tightly controlled, the effect of a given perturbation is found in changes in the selection of exercise intensity (or pacing strategy).  Therefore, the sole manner in which pacing strategy can be altered is if the perturbation is large enough in magnitude to alter RPE.  Herein lies the difference between our studies.  It is unlikely that the cooling modalities (either skin cooling or menthol) utilized by Barwood et al. [1] were sufficiently sustained or large enough in magnitude to alter RPE.  In contrast, by utilizing a significantly different experimental design to address the same question, we were successful in altering RPE.

The reason for this is likely four-fold, but certainly other rationale cannot be discounted.  Firstly, in contrast to the entire skin surface we chose to manipulate the skin of the face, an area that is both of high thermal sensitivity during heat stress [7] and an area that has been directly demonstrated to modulate exercise duration [8].   Secondarily, we used a greater concentration of menthol (8% vs. 0.05%) which, together with the facial manipulation, likely elicited a larger change in thermal perception.  Thirdly, we chose to use fit but untrained subjects, as trained individuals have an altered perception of their physiological thermal strain during exercise [9].   Thus, our subjects were likely more sensitive to changes in thermal perception.  The fourth, and perhaps final reason for the observed differences between these two studies likely stems from the exercise protocols used, i.e. fixed-RPE vs. time trial.  For instance, anecdotal observations from our laboratory suggest that the fixed-RPE protocol may be more sensitive to a given thermal stimulus than a time trial; although to our knowledge there is no formal data suggesting this arrangement.  Other rationale that should probably also be considered include the heat stress compensability and modality, exercise duration, and suitable subject blinding to the experimental conditions, amongst others.

In conclusion, we would like to commend Barwood and colleagues for their study and the data it adds to the literature.  However, we would urge caution before readers draw conclusions based on this study alone.  As it currently stands, the relationships between temperature, thermal perception, and exercise intensity remain uncertain and further research is required before conclusions can and should be drawn.  The differences between our study [5] and that of Barwood et al. [1] further highlight that the choice of experimental methodology may greatly influence a study’s outcome(s).  Issues pertaining to methodology are not specific to perception and exercise.  For instance, this journal recently highlighted another (equally debated) area, i.e. exercise and fluid replacement, which suffers from similar methodological concerns [10, 11].  Nevertheless, these studies [1, 5] endorse (and encourage) the use of menthol and other chemicals capable of affecting thermal perception without changing skin temperature in providing a useful paradigm to study the interactions between thermal perception and the voluntary control of exercise intensity.  Finally, as is the case with nearly all areas of research, we would encourage further studies in this area to ensure a better understanding and therefore, perhaps, a resolution to this interesting and topical area.

REFERENCES

1.         Barwood MJ, Corbett J, White D, et al. Early change in thermal perception is not a driver of anticipatory exercise pacing in the heat. Br J Sports Med 2011.

2.         Schlader ZJ, Stannard SR, Mundel T. Evidence for thermoregulatory behavior during self-paced exercise in the heat. J Therm Biol 2011;36:390-6.

3.         Schlader ZJ, Simmons SE, Stannard SR, et al. Skin temperature as a thermal controller of exercise intensity. Eur J Appl Physiol 2011;11:1631-9.

4.         Schlader ZJ, Stannard SR, Mundel T. Is peak oxygen uptake a determinant of moderate-duration self-paced exercise performance in the heat? Appl Physiol Nutr Metab 2011;36:863-72.

5.         Schlader ZJ, Simmons SE, Stannard SR, et al. The independent roles of temperature and thermal perception in the control of human thermoregulatory behavior. Physiol Behav 2011;103:217-24.

6.         Schlader ZJ, Stannard SR, Mundel T. Human thermoregulatory behavior during rest and exercise – a prospective review. Physiol Behav 2010;99:269-75.

7.         Cotter JD, Taylor NA. The distribution of cutaneous sudomotor and alliesthesial thermosensitivity in mildly heat-stressed humans: an open-loop approach. J Physiol 2005;565:335-45.

8.         Ansley L, Marvin G, Sharma A, et al. The effects of head cooling on endurance and neuroendocrine reponses to exericse in warm conditions. Physiol Res 2008;57:863-72.

9.         Tikuisis P, McLellan TM, Selkirk G. Perceptual versus physiological heat strain during exercise-heat stress. Med Sci Sports Exerc 2002;34:1454-61.

10.       Mundel T. To drink or not to drink? Explaining “contradictory findings” in fluid replacement and exercise performance: evidence from a more valid model for real-life competition. Br J Sports Med 2011;45:2.

11.       Goulet ED. Effect of exercise-induced dehydration on time-trial exercise performance: a meta-analysis. Br J Sports Med 2011;45:1149-56.

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Zachary J. Schlader, PhD, Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, TX, USA

 Toby Mündel, PhD, School of Sport and Exercise, Massey University, Palmerston North, New Zealand