Keeping cool in the heat of things

Research Associate Professor Jason Lee is shown undergoing physiological testing during exertion in a climatic chamber. Metabolic, cardiovascular, thermoregulatory responses are commonly measured to quantify individuals’ responses to heat stress.

Research Associate Professor Jason Lee from the Department of Physiology and the Basic Science Lead PI of the Human Potential programme at the NUS Yong Loo Lin School of Medicine (NUS Medicine) is trying to get us all to chill – literally.

An expert in how the human body regulates itself in hot climates – a process called thermoregulation – his research looks at how human health and performance are affected by heat, and developed heat mitigation strategies to cool the body down. 

Assoc Prof Lee discusses his work as a leading member of the Global Heat Health Information Network and as the Chair of the Scientific Committee on Thermal Factors at the International Commission on Occupational Health, how COVID-19 is shaping research on heat management strategies, and how hailing from warm and sunny Singapore gives him a different perspective on things.

Q: How did you first become interested in the human body’s heat-regulation ability?

A: It was during a second-year undergraduate module – called Exercise Physiology – in my Sports and Exercise Science Degree in the UK that I first learned about thermoregulation. I was fascinated by the underlying mechanisms and could relate the subject to what I experienced at home in Singapore during outdoor play and in the military. From there, I knew I wanted to dig deeper into the science of thermal physiology.

Fun fact: as someone who was actually terrible academically prior to becoming a top undergraduate student, I am a strong believer in that piece of advice – only devote yourself to what you like.

Q: Why do you focus your research in heat stress and heat management techniques and what impact do you aim to have?

A: Initially, I considered becoming a professional soldier, having served as a Commando officer during National Service, but I then decided to complete a degree in Sports and Exercise Science first as I love sports! I thought that would open up more options for me – including becoming a Physical Education teacher as I could go to work dressed in shorts and a T-shirt. I previously enjoyed my military experience and in a nugget of wisdom, my wife said that I perhaps could become a military physiologist instead of becoming a soldier. At that moment during a Sunday walk in the park in East Midlands, UK, I knew immediately that would be the job for me! 

From there, I went on to complete a doctoral degree under sponsorship from the UK Overseas Research Scholarship and Faculty Studentship. 

My 12-year tenure at the DSO National Laboratories furthered my knowledge in thermal physiology as well as designing what I called a “holistic heat management system”. This was achieved through profiling the associated heat strain in humans under various settings; formulating and evaluating heat mitigation strategies, such as physical conditioning regimes, heat acclimatisation, pre-activity cooling, work-rest cycles and hydration; and finally translating them into high quality scientific papers as well as policies and guidelines.

In terms of impact, I simply want to apply my knowledge to benefit mankind, especially those who are most vulnerable.

Q: What do you do as a leading member of the Global Heat Health Information Network, and what are some chief considerations when making recommendations or publishing guidelines?

A: I recently worked closely with fellow colleagues around the world to develop a new set of new guidelines that are focused on heat management strategies for the ongoing COVID-19 pandemic.

We are aware that some of the guidelines for traditional heat management and infection control can be contradictory. For example, the wearing of personal protective equipment  for infection control can induce a significant degree of thermal strain in healthcare workers.

Because the guidelines that we drew up were meant for an international audience, we had to consider more constraints and I could not just contribute solely based on Singapore’s context and considerations.

Q: In your role at Global Heat Health Information Network and International Commission on Occupational Health, does hailing from Singapore's warm climate give you a different perspective from your colleagues?

A: Yes, in some ways. A warm and humid environment is very much the norm for us in Singapore, so some of the behavioural and physiological heat mitigation strategies we have developed here could also be applicable to others who are dealing with periodic heat stress.

The COVID-19 pandemic is expected to go on for quite a while, but we are blessed with the resources to provide the best for our healthcare workers, which cannot be said for some parts of the world. As such, we need to “calibrate” our guidelines accordingly. Cheap and practical options are always the most welcome!

Q: What can people living in warm countries like Singapore do to stave off the effects of heat stress in their daily lives?

A: It depends on their living conditions. Not all of them will have the resources to harness the array of behavioural, physiological and engineering solutions to combat heat.

However, it is important that we make known the various ways and their associated costs and benefits so that people who are experiencing thermal strain or those responsible for these people can safeguard their wellbeing, health and work productivity.

For example, whenever possible, avoid working hard in the heat. Adopt behavioural strategies such as slowing down, keeping work short, and resting more.

If work quality or quantity needs to be maintained, harness a series of physiological strategies in this order – be aerobically fit, get yourself heat acclimatised, use internal strategies such as ingesting ice slurry, and exertional cooling strategies such as taking cold baths, and stay hydrated.

Each of these strategies can improve heat tolerance. Doing all will have an accumulative effect.

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Assoc Prof Lee recommends five heat mitigation strategies to safeguard our well-being, health and productivity.

Q: What are you presently researching on, and what is on your radar in future?

A: We have just been awarded funding to undertake research to look at the impact of heat on health and work productivity in Singapore and selected countries in our region. The new Human Potential Programme at NUS Medicine, where I am serving as the Basic Science Lead PI, will provide an ideal platform for us to conduct studies to derive new methods in dealing with heat stress in both healthy and unhealthy populations.

At the Department of Physiology, my colleagues and I are putting together a new Continuing Education and Training module to impart knowledge specific to periodisation and heat management under exertional settings.

At N.1 Institute for Health, I seek to harness artificial intelligence to uncover inter-individual responses to heat stress, and at NUS Global Asia Institute, I am working closely with other experts in economics and behavioural sciences to augment this research mandate. The way ahead is an interdisciplinary approach, which not only goes in-depth but which also cuts across disciplines to address an important problem.