The Physiological Society                                                                                                                HRSC0006

The Physiological Society                                                                                                                HRSC0006

Written evidence submitted by The Physiological Society

Background:

The Physiological Society (The Society) is Europe’s largest network of physiologists, at the forefront of science for

147 years.[1] Physiology is the science of life, and research in physiology helps us to understand how the body works in health, what goes wrong in disease, and how it responds and adapts to the challenges of everyday life. The Society’s membership is made up of researchers in all these areas, from neuroscience through to endocrinology, nutrition and sport and exercise science, with the science ranging from the mechanistic to the applied, from molecular to whole body.

Physiology is an essential part of the scientific response to the climate crisis as it helps us understand the consequences of climate change for humans and other animals. As the science of how the body works, physiology explains the impact of climate change on our health and productivity, as well as the scope we have for mitigating and adapting to climate change.

As such, The Society is committed to using physiological research to improve the heat resilience of the population. We have produced two reports Physiology and Climate Change and The Climate Emergency: Research Gaps and Policy Priorities.[2] Together, the reports discuss measures individuals can take to protect themselves and how governments, civil society and research funders respond to the policy challenges that the climate emergency presents. We are also members of the UK Health Alliance on Climate Change (UKHACC).

Consultation response:

1. What evidence exists on the relationship between heat and human health (mortality and morbidity), and which communities are worst affected?

Prolonged exposures to heat, especially the lack of night time recovery due to high overnight temperatures significantly impacts human health and increases morbidity and mortality. High temperatures can exacerbate cardiovascular and kidney disease as well as lead to stroke.[3]

Some communities and populations are more vulnerable to the impact of climate change than others. These include older people, people living with co-morbidities, pregnant women, disadvantaged groups, indigenous populations, and ethnic minorities.[4] Pre-existing health issues such as heart conditions and diabetes make people more vulnerable to heat stress as do certain medications that impact thermoregulation (by reducing blood flow to the skin), increasing heat production or reduce sweating (such as diuretics, antihypertensives, antihistamines, beta blockers, stimulants; certain drugs for epilepsy and Parkinson’s).

Pregnant women are also adversely impacted by heat which can lead to poor birth outcomes for the foetus such as pre-term birth and low birthweight. This is linked to poorer long-term health outcomes such as cardiovascular disease.[5]

People working in extreme heat conditions especially those who wear personal protective equipment (PPE) and other outdoor workers, such as farmers and builders, can also be at risk due to increased exposure to high heat loads, combined with high heat energy expenditure/heat production.

Lastly, there is a lack of lab-controlled evidence on the impact of chronic exposure to heat (i.e. there is limited controlled environment data available to demonstrate how long-term exposure to extreme heat can affect overall health outcomes).

2. How can sustainable cooling solutions and adaptation strategies be implemented in such a way as to minimise overheating, reduce energy consumption and prevent overloading of the electricity grid during peak demand?

The Physiological Society’s report The Climate Emergency: Research Gaps and Policy Priorities notes the use of thermal physiological principles to develop effective and sustainable cooling strategies.4 This includes understanding the relative importance of skin and deep body temperatures in determining the perception of human thermal comfort and thermoregulatory responses. Such understanding enables evaluation of cooling techniques such as, evaporative cooling techniques, through which evaporated water is used to cool hot air that can be used as alternative to the current fossil-fuelled powered HVAS systems.

Greening cities with trees, community parks and rooftop gardens can keep urban communities cooler amid rising temperatures. This would require cross-disciplinary collaboration between physiologists, botanists, architects and the local government.

3. What actions can be taken to protect those most vulnerable to the impacts of extreme heat?

It is important we prioritise the protection of those most vulnerable to the impacts of extreme heat. Heat resilience strategies should be developed to include guidelines specifically for older and vulnerable populations.

The Government must ensure that their homes are equipped with sustainable, low-energy demand cooling technologies. Sources of indoor air pollution must be minimised to ensure that indoor air quality is good. This measure is particularly important as some vulnerable people are more likely to spend their time indoors sheltering from extreme heat.

Outdoor workers are also more vulnerable to the impacts of extreme heat. Workers may have to avoid working during peak hours of heat, employers may have to consider providing micro-climate conditioning systems and hydration strategies.. They should also be supported with legally mandated and enforced work-rest schedules.

Lastly, in order to build heat resilience, it is vital to take a public health approach wherein people remain physically fit and active throughout their lives. Lifelong exercise and good nutritional strategies are critical to developing heat resilience in older adults. For example, encouraging people to consider active travel such as cycling or walking will not only improve people’s health and wellbeing, but also contribute to a reduction in emissions. Building public resilience to heat through improved individual physiology is therefore vital. Further, it is also important that policies to tackle climate change are linked to preventative health and healthy ageing policies.

4. To what extent do the Government’s Climate Change Risk Assessment and National Adaptation Programme (as well as other related strategies such as the Net Zero Strategy and Heat and Buildings Strategy) identify and address the risks from extreme heat?

The Government’s climate change adaptation strategies fail to include measures to mitigate or reduce the impact of extreme heat events on emergency and rescue workers. These workers will increasingly be called upon due to the increase in frequency and intensity of extreme heat events.

Further research is needed to understand the physiological demands of rescue workers during extreme events in order to develop effective strategies to optimise their health, safety and function. This could include the design of PPE, job-specific training, reducing the length of shifts and nutritional and recovery strategies, such as proper work rest schedules and hydration.

Government measures and strategies in this area should be underpinned by an understanding of the physiological and pathophysiological responses to heat. This understanding will help in not only mitigating and adapting to the impact of heat, but also in treating the impacts of extreme heat.

6. What can be done to protect the UK’s existing public and private sector housing stock from the impacts of extreme heat while ensuring that homes are sufficiently warm in the winter months?

Protecting the UK housing stock from the impacts of extreme heat would require a range of interventions based on the physics and physiology of temperature regulation. By understanding the drivers of human thermal comfort and promoting natural convection we can prevent greenhouse warming inside houses. This can also include measures to cool the macroenvironment naturally.

Physiologists should be engaged by those retrofitting and building new houses to ensure a human health-centric approach to protecting the UK housing stock from extreme heat.

7. What role might reversible heat pumps (which can act as both heating and cooling systems) and other emerging technological solutions, such as the development of smart materials, play in meeting future cooling demands?

Emerging technological solutions such as reversible heat pumps, will play an important role in meeting future cooling demands. However, they must be focused on achieving targets rooted in an understanding of the physiology of human temperature regulation.

11. Does the UK need a dedicated Heat Resilience Strategy? What lessons can be learned from other nations when it comes to national strategies for heat resilience?

The UK needs a dedicated Heat Resilience Strategy to ensure cross-departmental and organisational collaboration in response to extreme heat events. This strategy should include separate sections on protecting vulnerable populations from the impacts of extreme heat; such as worker protection policies for outdoor workers.

The Strategy should incorporate physiologically-informed solutions to tackling the impact of extreme heat on human health. It is also vital to include other measures for increasing population resilience such as encouraging exercise and developing good nutritional strategies. For example, physiological knowledge and assessments can be used to improve plant nutritional profiles so that they match the dietary provision of animal products to develop sustainable diets, reducing emissions from agriculture.

The lessons that we can learn from other countries include having a chief officer who is responsible for examining local heat resilience and developing recommendations, such as the US city of Miami who as a dedicated Chief Heat Officer. The city has also developed a Climate and Heat Health Task Force. Other cities such as Los Angeles, Athens and Melbourne have also appointed Chief Heat Officers. Further, Sierra Leone has implemented a Shield Cover project for outdoor workers who spend long hours labouring in extreme temperatures.[6]

August 2023